RE: using new technology on old machines. Was: PDP-12 Restoration at the RICM
-Original Message- From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Chuck Guzis Sent: 15 June 2015 18:25 To: gene...@classiccmp.org; discuss...@classiccmp.org:On-Topic and Off- Topic Posts Subject: Re: using new technology on old machines. Was: PDP-12 Restoration at the RICM On 06/14/2015 12:41 PM, Simon Claessen wrote: as long as it is done in a way that it can be restored to its original, i have no problems in using newer technology in older machines. we have a alix sbc build into our tek 4002a for demonstrational purpouses, all done without damaging or altering the original machine. I'm a bit more pragmatic. Whatever it takes to get something running, I'll do it. For me, that's the entire point of having the old stuff around. Otherwise, a non-working box is scarcely better than any other piece of antique e- waste. I think so long as the machine isn't unique then I think this is a reasonable approach to take. If there's an accurate emulation available on modern hardware, I'll use that rather than play with some old, cranky piece of iron. That can be fun to. Others may certainly have different opinions. I think you have to be pragmatic. I have now finished my Baby Baby Video here:- https://youtu.be/OGcAmrFoRrY Its pretty much cycle accurate... --Chuck Dave G4UGM
Re: using new technology on old machines. Was: PDP-12 Restoration at the RICM
Not all EE's have the same education with regard to how semiconductors function. When I was in school I took a class in semiconductor physics - an entire semester on how the wee beasties function - more than most EEs. The prof., Henry Guckel, told an interesting story about an advanced IBM computer he did some work on (not sure if it was the ACS or one of the 9x models). The clock ran really fast, and they were had all kinds of problems with propagation delays - for which their typical cure was to add delay lines - to the point where it slowed down the machine so much that they actually had to back off the clock some. He also didn't like computer programmers very much. Another related story: a pre-requisite for the class was a modern physics class - which was horribly taught, by a prof. the physics department. During the 2nd class or so, Prof. Guckel noticed a lot of deer in headlights looks, and stopped. After commenting that the material should have been largely review, he asked when and from whom we had taken the modern physics class - and 3/4 of the class had taken the class from the same prof. during the previous 12 months. After realizing that class had been a disaster, Prof. Guckel spent the next 4 lectures re-teaching most of that entire-semester class - and doing a really good job of it - preparing his own notes and everything, before proceeding through the rest of the class. Really tough course. On 7/13/2015 6:18 AM, Tor Arntsen wrote: I think I'm reasonably well into the pragmatic camp (ref. Chuck G.'s post). But one point about 555s and Arduinos is that I couldn't build a 555 more easily than I could build the MCU on an Arduino board (a more relevant comparision might be a 555 vs a Propeller chip) - they're all black boxes to me. Even a transistor, to some extent - I know exactly how it works, well, as much as any other EE anyway, but I couldn't build one. Or a vacuum tube..
Re: OT: learner kits (was: Re: using new technology on old machines)
On Jun 19, 2015, at 19:19 , Tapley, Mark mtap...@swri.edu wrote: He has a Raspberry Pi, which he pretty much contempts in favor of his laptop, which will play the modern version of MineCraft :-P, but presumably hooking those together might be fun. I suspect that boards like the Raspberry Pi, Arduino, etc. might get a lot more interesting if they can affect the real world. See if a servo motor adds some appeal. -- Mark J. Blair, NF6X n...@nf6x.net http://www.nf6x.net/
OT: learner kits (was: Re: using new technology on old machines)
All, My 14-year-old son has mentioned that he’d like a breadboard and some parts to fool with, and the pointer below really helps. I have an old Archerkit VOM already, and I’m thinking about turning him loose in August with the discrete components part kit, the VOM, a box of logic parts, and a copy of Horowitz and Hill. Is there a reason to prefer 7400 series over CD4000 series logic? http://www.jameco.com/Jameco/catalogs/c151/P30.pdf makes the CD4000 series look cheaper. I also have a pair of old Tek 922 O-scopes, one of which has all of its knobs and switches intact and produces a trace. I’ll guess that they both need rebuilding; I have the instruction manuals, though, so maybe that is lesson 1? Is the TekScopes group the best place to find probes for one or both? I also have one of the 200-in-1 spring-termial projects; he played with that a bit, but there wasn’t enough logic there to do much computing :-) so he lost some interest. He has a Raspberry Pi, which he pretty much contempts in favor of his laptop, which will play the modern version of MineCraft :-P, but presumably hooking those together might be fun. Should I add anything else to his pile? Is there a series of logic that’ll make things easier if he does end up hooking in the RPi? Thanks for any help! My own knowledge is pretty spotty in this field, so please feel free to start near ground-zero with helpful advice. - Mark On Jun 16, 2015, at 10:50 AM, geneb ge...@deltasoft.com wrote: On Tue, 16 Jun 2015, Mark J. Blair wrote: On Jun 16, 2015, at 08:19, geneb ge...@deltasoft.com wrote: On Tue, 16 Jun 2015, Noel Chiappa wrote: I wish there was some _easy_ way to lay in a stock of the most common TTL IC's - e.g. some kind of kit one could buy - but alas, I don't know of any. (Hence my dream of finding and acquiring someone else's collection! :-) Suggestions for the source of such a good diversified 'starter kit' welcome... How about this: http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_84961_-1 Very nice! I might just order one of those. They also offer 4000 series, transistor, resistor, and capacitor collections. g. -- Proud owner of F-15C 80-0007 http://www.f15sim.com - The only one of its kind. http://www.diy-cockpits.org/coll - Go Collimated or Go Home. Some people collect things for a hobby. Geeks collect hobbies. ScarletDME - The red hot Data Management Environment A Multi-Value database for the masses, not the classes. http://scarlet.deltasoft.com - Get it _today_!
DEC M452 module oscillator/ was Re: using new technology on old machines
On 2015-Jun-17, at 7:31 AM, Dave G4UGM wrote: From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Noel Chiappa From: Dave G4UGM I found it easier to think of it in DC terms. So the Cap charges through R5 + R3 and R9 + R8. As the Cap charges the voltage on the base of Q1 rises until it turns on, which then turns on Q2. At this point the cap is then charged (or discharged) in the reverse direction via Q2, D5 and R4 until Q1 turns off. I'm clearly never going to be any good at analog stuff! ;-) Even with what looks (on the surface) to be a wonderfully clear explanation of how the circuit works, I still can't really grok how it operates! I mean, I can tell from the polarity on the cap that the collector of Q2 must be at a higher voltage than the base of Q1, but I am utterly failing to understand how the cap discharges through Q2. And as the cap charges (i.e. the voltage across it increases), how does the voltage on the base of Q1 increase - surely it must be decreasing (since it's tied to the negative side of the cap, which is experiencing a voltage increase across itself)? I think the cap is mildly abused. I believe that it is reverse charged. While I was at the bench working on another project I took a couple of minutes to breadboard the circuit (Q1-Q3), turns out it switches before the capacitor goes into reverse charge, so the cap does retain the proper polarisation throughout the charge/discharge operation cycle. Experimented with separating R8/R9 into isolated emitter-bias and collector-load resistors, can still be made to oscillate but becomes more touchy, so I do suspect the particular oscillator design was chosen for stability, also considering a common flip-flop astable could have been in fewer components. (Coincidentally, the other project was repairing one of those common flip-flop astables (master clock in a 1971 calculator) which was intermittent. Measurements ruled out the Rs as a problem, so narrowed it down to the two transistors and the two capacitors, at which point it became a question of shotgun replacing all 4 components versus trying to isolate it further. Tried individual hot / cold checking of the 4, the osc. rigorously stopped with heat applied to a 60pF ceramic cap and restarts after blowing it cool.)
Re: using new technology on old machines. Was: PDP-12 Restoration at the RICM
On Mon, Jun 15, 2015 at 10:53:33PM +0200, Pontus Pihlgren wrote: On Mon, Jun 15, 2015 at 04:53:01PM +, tony duell wrote: I also think it is in the spirit of the computer - using what is available to fix a problem at hand. I think the arduino was overkill when an attiny (smaller, easier to hide) would probably serve just as well. Would you put plastic handles on a piecc of antique furniture? Would you make the seatboard for an antique longcase clock from MDF? Both are easily reversable, BTW. No but I would put an electric heater in a steam engine if it meant restoration would progress faster. (yes, feel free to lecture me how big that heater would have to be...) That has been done before for production purposes. I kid you not. Happened in Switzerland during WW2. Due to the war, coal was a bit in short supply, but Switzerland already back then had plenty of (hydro-) electric power, including on the railway grid. So they converted a few steam locomotives to steam-electric by replacing the firebox with electric heaters. IIRC it was only a few locomotives and they were mostly used for shunting work. Kind regards, Alex. -- Opportunity is missed by most people because it is dressed in overalls and looks like work. -- Thomas A. Edison
Re: using new technology on old machines. Was: PDP-12 Restoration at the RICM
(I would change the subject line, but I am not sure how to do it in my ISP's web mail client) As far as I know XH558 will be permanently stationed at Finningley after this year's flying season is completed. The full details are here: http://www.vulcantothesky.org/, including dates of flypasts and displays. Regards Rob On 17 June 2015 at 12:16, Christian Gauger-Cosgrove captainkirk...@gmail.com wrote: On 17 June 2015 at 05:09, Huw Davies huw.dav...@kerberos.davies.net.au wrote: Funny I was discussing just this pair of planes last night - I last saw them fly in 1971 at RAF Shawbury. Of course they were both in active service then and I remember watching the Lightning do a supersonic pass with much joy. Off topic for a moment but, do you know perchance what's going to happen to XH558 at the end of this year? I've never had a chance to see a flying Vulcan, and it's too bad I won't ever get to see one (nor did I get to see the awesome display of both of he flight worthy Lancasters flying together last year...). Getting a little closer to the topic at hand, eventually parts will no longer be available for older computers so the decision will have to be made to either retire them or use more modern components to keep them going. Somewhat ironically the ones that can be maintained in ‘original' condition for longer may be the mechanical ones where replacement parts could be fabricated whereas valves and SSI TTL may not be able to be economically produced. The point you raise is comparable to the fact that we'vve basically flown the life out of the last Avro Vulcan, meanwhile here in my home town we're still managing to keep an Avro Lancaster flying after all these years. Also, I realize anyone can infer where I live based on the statements in this e-mail, hah. Cheers, Christian -- Christian M. Gauger-Cosgrove STCKON08DS0 Contact information available upon request.
Re: Windows and devices - was Re: using new technology on old machines. Was: PDP-12 Restoration at the RICM
On Jun 17, 2015, at 10:50 , Toby Thain t...@telegraphics.com.au wrote: Here's a cute gotcha I hit this week: - Have a running Windows 8.1 machine with PS/2 keyboard. - Shut it down, start up with only USB keyboard. - Shut down and boot again with PS/2 keyboard atached. - Windows ignores it (although BIOS flashes lights normally, etc). - Registry change (found by google) reboot brings it back to life. Can't imagine how many good keyboards were dumpster'd over that one. Working in the GPS industry, I became all too familiar with how Windows can't tell the difference between a Microsoft Serial BallPoint and a 4800 baud NMEA stream. -- Mark J. Blair, NF6X n...@nf6x.net http://www.nf6x.net/
Re: RE: using new technology on old machines
On 2015-06-17 13:28, Dave G4UGM wrote: I found it easier to think of it in DC terms. So the Cap charges through R5 + R3 and R9 + R8. As the Cap charges the voltage on the base of Q1 rises until it turns on, which then turns on Q2. While the cap charges, it steals the base current which would otherwise have gone to Q1, thus keeping Q1 turned off. When the cap nears the end of the charge, more current goes to the base of Q1 which turns on, turning on Q2, which raises the voltage over R8 and R9. Since the voltage on a capacitor cannot change instantaneously, the voltage on the base of Q1 rises while the cap discharges through the base of Q1, keeping it hard on. As the cap discharges and charges in the reverse direction, the base current of Q1 decreases and ultimately Q1 turns off, turning off Q2 and lowering the voltage over R8 and R9, and the cycle starts over. For the circuit to work, I think (I may be wrong) the base current supplied to Q1 by R5 and the pot has to be not quite sufficient to turn it on. Also the cap is reverse charged for one half cycle. I believe this is a classical astable multivibrator circuit, but not the more common one with two cross-coupled transistors with capacitors from the collector of one to the base of the other. The DEC circuit I think can be seen a lot in old Siemens application books from the 1960s, such as may be found here (note German books): http://rainers-elektronikpage.de/SIEMENS-Fach---u_-Datenbucher/siemens-fach---u_-datenbucher.html /Jonas At this point the cap is then charged (or discharged) in the reverse direction via Q2, D5 and R4 until Q1 turns off. At first glance I thought R9 might be there to provide some hysteresis in the switching thresholds for the RC charge/discharge but it looks like it acts in the opposite direction to that. The base circuit of Q3 (the first stage of buffering) will draw current from the high-impedance side (R8,R9) of the oscillator output, pulling up the C5,R9 junction when Q2 is off, so it will probably affect the oscillator and be necessary to get the 'proper' functioning of the oscillator portion of the circuit. I included that in my LTSpice model ... but it doesn't actually have that much effect... Dave G4UGM
Re: using new technology on old machines. Was: PDP-12 Restoration at the RICM
On Mon, Jun 15, 2015 at 10:14:18PM -0700, Mark J. Blair wrote: On Jun 15, 2015, at 21:59, tony duell a...@p850ug1.demon.co.uk wrote: Even though there are at least 4 different USB connectors Ok, you got me there! When I was working for a GPS startup, I used mini-B on everything I designed with USB (always devices, never hosts, and no need for USB OTG). Then we got bought by a cell phone company and now everything's a godawful mix of mini-B and micro-B, with OTG thrown in there, too. Grrr! Well, micro-B is the better choice since it is designed for more plug cycles than mini-b, designed to minimize wear on the socket and instead wear out the (cheap, easy to replace) cable and it actually locks in the socket, so is much less likely to slip out. I'm cursing everytime some device comes with a mini-B connector these days instead of micro-B. IMHO USB got round the problem of null-modem cables by making them impossible. Which to me is not an improvement. I guess USB is OK when it works (like plugging in a memory stick) but a right pain to debug when it doesn't. And having read the standard there is much I dislike about it. Maybe this isn't the best time or place for this particular rant, but in my opinion, Windows' implementation of USB is fundamentally broken. It's a mouse, you stupid computer! You shouldn't need to spend a minute or more installing a new device driver for it! And you shouldn't need to install the driver yet again if I poke it in a different hole than I did last time! Every other *** OS on the planet is smart enough to say Oh, a mouse! I know how to use those! within a handful of milliseconds! Windows does what (haven't used a Windows box for a long time)? Now that is retarded. I'm used to my systems (Linux, *BSD) just going oh, this is a keyboard/mouse, no problem, I can handle this and stuff quietly works. Kind regards, Alex. -- Opportunity is missed by most people because it is dressed in overalls and looks like work. -- Thomas A. Edison
Re: using new technology on old machines
The M452 module schematic for quick access for anyone following along, as it hasn't been linked before in the thread: http://bitsavers.informatik.uni-stuttgart.de/pdf/dec/modules/mSeries/M452.pdf
RE: using new technology on old machines
That's only the schematic. The link I included earlier:- http://dustyoldcomputers.com/pdp-common/reference/drawings/modules/m/m452.pd f also includes the PCB component layout, from which I inferred the Trim Pot is of the 10-turn variety. Dave -Original Message- From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Brent Hilpert Sent: 17 June 2015 09:28 To: General Discussion: On-Topic and Off-Topic Posts Subject: Re: using new technology on old machines The M452 module schematic for quick access for anyone following along, as it hasn't been linked before in the thread: http://bitsavers.informatik.uni- stuttgart.de/pdf/dec/modules/mSeries/M452.pdf
Re: using new technology on old machines
From: Dave G4UGM I found it easier to think of it in DC terms. So the Cap charges through R5 + R3 and R9 + R8. As the Cap charges the voltage on the base of Q1 rises until it turns on, which then turns on Q2. At this point the cap is then charged (or discharged) in the reverse direction via Q2, D5 and R4 until Q1 turns off. I'm clearly never going to be any good at analog stuff! ;-) Even with what looks (on the surface) to be a wonderfully clear explanation of how the circuit works, I still can't really grok how it operates! I mean, I can tell from the polarity on the cap that the collector of Q2 must be at a higher voltage than the base of Q1, but I am utterly failing to understand how the cap discharges through Q2. And as the cap charges (i.e. the voltage across it increases), how does the voltage on the base of Q1 increase - surely it must be decreasing (since it's tied to the negative side of the cap, which is experiencing a voltage increase across itself)? Like I said, I apparently don't have the gene for analog... :-) Noel
RE: using new technology on old machines
-Original Message- From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Noel Chiappa Sent: 17 June 2015 15:08 To: cctalk@classiccmp.org Cc: j...@mercury.lcs.mit.edu Subject: Re: using new technology on old machines From: Dave G4UGM I found it easier to think of it in DC terms. So the Cap charges through R5 + R3 and R9 + R8. As the Cap charges the voltage on the base of Q1 rises until it turns on, which then turns on Q2. At this point the cap is then charged (or discharged) in the reverse direction via Q2, D5 and R4 until Q1 turns off. I'm clearly never going to be any good at analog stuff! ;-) Even with what looks (on the surface) to be a wonderfully clear explanation of how the circuit works, I still can't really grok how it operates! I mean, I can tell from the polarity on the cap that the collector of Q2 must be at a higher voltage than the base of Q1, but I am utterly failing to understand how the cap discharges through Q2. And as the cap charges (i.e. the voltage across it increases), how does the voltage on the base of Q1 increase - surely it must be decreasing (since it's tied to the negative side of the cap, which is experiencing a voltage increase across itself)? I think the cap is mildly abused. I believe that it is reverse charged. Like I said, I apparently don't have the gene for analog... :-) Noel
Re: using new technology on old machines. Was: PDP-12 Restoration at the RICM
On Jun 16, 2015, at 06:46, tony duell a...@p850ug1.demon.co.uk wrote: Again, I wonder if the data retention time decreases as the number of bits per device increases. Intuitively it should. Mind you, any SD card is probably going to be more reliable than a real TU58 tape now :-) I think that paper tape, used outdoors on a rainy day, is likely to be more reliable than a real TU58 tape. :) -- Mark J. Blair, NF6X n...@nf6x.net http://www.nf6x.net/
RE: using new technology on old machines
Sure, the pre-manufactured boards can allow you to prototype quickly... but I think Tony is kind of bemoaning the loss of the old way and I respect that ... I kind of miss it myself, even though I wasn't there to experience it first-hand ... It's also that this is the 'classic computers' list. To me, classic computing means rather more than just the hardware. It also covers the design and construction methods, technology and so on. And there seems to be precious little of that in a modern microcontroller acting as a clock oscillator. I find it odd that people want to have a lights-and-switches panel, but are prepared to totally adulterate the hardware of the machine that drives it. As an aside, when I restore m 11/730 I am in 2 minds as to what to do about the microcode load device. a TU58 emulator is certainly convenient, but I actually would rather get the real tape drives working if at all possible. After all that is what the machine was designed to use. How are everyone's parts bins so empty? My dad is a practicing EE of over Mine isn't, but then you knew that, right :-). When I moved house recently I think I had over 30 packing boxes of modern-ish components and more of valves and CRTs. Not counting the dozen or so boxes of PCBs (some to use, some to raid for parts). -tony
RE: using new technology on old machines. Was: PDP-12 Restoration at the RICM
I am of course counting all the transistors inside that chip. Well, that was obvious. But it raises an interesting point, today you can cram a whole computer in the footprint of the simplest DIP carrier. For the same price point and same reliablity. Is it then overkill if you choose to use thousands of those transistor over using just 10 ? Is it as reliable, though? You will get no argument from me that the _same design_ is more reliable the more 'LSI' it is -- that is a processor as a single chip is more reliable than the same design in TTL which in turn is more reliable than the same design in discrete transistors. But when you compare different designs, I am not conviced. My experience is that I have had to replace many more LSI ICs than TTL and many more TTL chips than transistors (power transistors, choppers, line output transistors excpeted!). I am not at all convinced that a microcontroller is as reliable as a 555 timer. After all, microcontrollers presumably store their firmware in some kind of flash memory which is going to suffer from bit-rot. A 555 doesn't. Similar to Mark's example of using just the first bytes of an SD card with gigabytes of storage. Again, I wonder if the data retention time decreases as the number of bits per device increases. Intuitively it should. Mind you, any SD card is probably going to be more reliable than a real TU58 tape now :-) -tony
Re: using new technology on old machines. Was: PDP-12 Restoration at the RICM
Choosing the larger card is, IMO, the right answer because you don't actually waste the space, you extend the life significantly because the wear leveling will spread your 256K across the entire flash region. The larger that region, the less often you re-write the same cells, thereby extending the life of all the cells. Chris On Monday (06/15/2015 at 03:06PM -0700), Mark J. Blair wrote: On Jun 15, 2015, at 14:56 , Dave G4UGM dave.g4...@gmail.com wrote: A friend of mine refused to buy modern SD Cards because there was no way he was going to fill them. Trouble is that although smaller SD cards were available they were way more expensive (being discontinued and therefore rare and valuable).. He struggled with buying a larger card only to waste most of it, or buy a smaller one and waste his money I had that same mental hangup when thinking about how I might design an SD card based TU58 emulator in the same form factor as a TU58 cartridge (still on my to-do list, by the way). How was I going to implement the user interface? It's not like there's much room for an LCD or buttons on the edge of a TU58 cartridge. Then it finally hit me: SD cards are cheaper than TU58 cartridges ever were. So why not just use the first 256k, ignore the rest of the card, and swap cards exactly the way one would swap TU58 cartridges, with one image on each card? Yeah, 99% of the card is wasted, but they're presently cheap and plentiful enough to ignore that. Ok, I might actually have the emulator read a file from a DOS filesystem rather than using the first 256k of raw blocks. But it'll probably just be a fixed filename with no controls to select a different one, and the expectation that an entire (cheap, plentiful) SD card will be devoted to each tape image. At least this way, other things can also be on the card, so it doesn't need to be wasted if not needed. Your friend should understand that the larger card that he would be wasting probably has less silicon in it than the older one with less capacity. The cheapest card that is reliable, fast enough and large enough for his task is the best one to get, even if it's much larger than he needs. Just one of the weird parts of the Moore's Law curve! Hmm, this reminds me that back in the day, floppy disks were expensive. We have it easy with cheap and plentiful SD cards nowadays. But maybe my perspective is different as an employed adult rather than a teenager with limited funds? Anyway, SD cards seem to be cheap enough to be nearly disposable nowadays. -- Mark J. Blair, NF6X n...@nf6x.net http://www.nf6x.net/ -- Chris Elmquist
Re: using new technology on old machines
From: tony duell One method that works for me is that if you are buying a fairly cheap part, buy 10 of them and put the rest in stock. Or more than 10 if it is something really common. I suspect a lot of us do that - that's why I have tubes of 4164's, etc, for instance. It makes a lot of sense, because it's trivial to implement - it's just as much work to order 10 of something, as 1. But that model isn't really the best, because a lot of the time one winds up needing something one doesn't already have. Which is why it's better to lay in a diversified stock up front. E.g. in wood screws (I do a lot of work in wood, mostly furniture), I have a fairly comprehensive collection; from #6 through #12, all the available lengths (not the very longest ones, though), counter-sunk and round-headed, with both slot and Phillips drive. But doing so in IC's - oi vey! Just in TTL alone, there are dozens of common parts (hundreds, if you count the more obscure ones), and then you get into the whole 74, 74S, 74LS, 74ALS, 74L, 74H, 74F, yadda-yadda. Of course, most of the variants one would never need, but one can't get by with just, e.g. LS; e.g. if I ever get my wish and wind up with a PDP-11/45, that's mostly S, IIRC. I wish there was some _easy_ way to lay in a stock of the most common TTL IC's - e.g. some kind of kit one could buy - but alas, I don't know of any. (Hence my dream of finding and acquiring someone else's collection! :-) Suggestions for the source of such a good diversified 'starter kit' welcome... Noel
Re: using new technology on old machines. Was: PDP-12 Restoration at the RICM
On Jun 16, 2015, at 07:36, Chris Elmquist chr...@pobox.com wrote: So, now you have to use a Type A to Type A cable to connect this box to your computer. That is just really, really messed up and I honestly tried to make it right but it was like pushing a rope. I hope my friends will visit me in prison. Sounds to me like you are more of a victim than a perpetrator here. Isn't there some OSHA regulation against USB A to A cables? :) -- Mark J. Blair, NF6X n...@nf6x.net http://www.nf6x.net/
Re: using new technology on old machines
On Tue, Jun 16, 2015 at 04:18:03PM +, tony duell wrote: [Build your own 11/70] Oh, very much! Then we could have a discussion about using modern switching power supplies ot not ;-) As opposed to the original 11/70 switching supply? I would suspect that modern switchers are more efficient. If I wanted to have one running for any longer extent I would consider an upgrade. Only reversible changes of course. /P
Re: O/S design implementation - was Re: FPGA tricks - Re: using new technology on old machines
On Jun 15, 2015, at 9:21 PM, ben bfranc...@jetnet.ab.ca wrote: On 6/15/2015 7:11 PM, Paul Koning wrote: On Jun 15, 2015, at 8:09 PM, ben bfranc...@jetnet.ab.ca wrote: On 6/15/2015 4:42 PM, Toby Thain wrote: I think Tanenbaum should be fine? A lot of it is fairly timeless. The latest version is *useless*. The racoons on the cover tells alot. Or you could just read “The structure of the THE operating system” by E.W.Dijkstra, and follow its principles. a) Not online to my knowledge http://www.cs.utexas.edu/users/EWD/ewd01xx/EWD196.PDF — the same site that has the full archive of all EWD papers (except for some very early ones that have been lost) — a total of 1300 or so. b) Most likely in German None are in German, naturally, since Dijkstra was Dutch. Some early ones are in Dutch, but this one is in English. c) and the most important thing ... I do not have any Mag Tape Not relevant; the THE OS does not rely on magtapes. It uses drum for paging and spooling, but the design is nicely layered so the system also works without drum (this is explicitly mentioned in one of the reports on its development). In any case, I did not point to this paper as a specific OS to implement, but rather as a demonstration of how to design a modest size but quite useful OS, with very modest effort and extremely high reliability. EWD1303 (http://www.cs.utexas.edu/users/EWD/ewd13xx/EWD1303.PDF) is another note about that effort, looking back from 2000. paul
Re: using new technology on old machines
On Jun 16, 2015, at 08:19, geneb ge...@deltasoft.com wrote: On Tue, 16 Jun 2015, Noel Chiappa wrote: I wish there was some _easy_ way to lay in a stock of the most common TTL IC's - e.g. some kind of kit one could buy - but alas, I don't know of any. (Hence my dream of finding and acquiring someone else's collection! :-) Suggestions for the source of such a good diversified 'starter kit' welcome... How about this: http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_84961_-1 Very nice! I might just order one of those. -- Mark J. Blair, NF6X n...@nf6x.net http://www.nf6x.net/
Re: using new technology on old machines. Was: PDP-12 Restoration at the RICM
Again, I wonder if the data retention time decreases as the number of bits per device increases. Intuitively it should. Mind you, any SD card is probably going to be more reliable than a real TU58 tape now :-) I think that paper tape, used outdoors on a rainy day, is likely to be more reliable than a real TU58 tape. :) You got a thumbs-up! (In Brazil we call it Joinha) :)
Re: using new technology on old machines. Was: PDP-12 Restoration at the RICM
On Tuesday (06/16/2015 at 07:24AM -0700), Mark J. Blair wrote: On Jun 16, 2015, at 06:46, tony duell a...@p850ug1.demon.co.uk wrote: Again, I wonder if the data retention time decreases as the number of bits per device increases. Intuitively it should. Mind you, any SD card is probably going to be more reliable than a real TU58 tape now :-) I think that paper tape, used outdoors on a rainy day, is likely to be more reliable than a real TU58 tape. :) I can vouch for that. -- Chris Elmquist
Re: using new technology on old machines. Was: PDP-12 Restoration at the RICM
On Tuesday (06/16/2015 at 07:43AM -0700), Mark J. Blair wrote: On Jun 16, 2015, at 07:36, Chris Elmquist chr...@pobox.com wrote: So, now you have to use a Type A to Type A cable to connect this box to your computer. That is just really, really messed up and I honestly tried to make it right but it was like pushing a rope. I hope my friends will visit me in prison. Sounds to me like you are more of a victim than a perpetrator here. Isn't there some OSHA regulation against USB A to A cables? :) well, you know, it's a different world these days. You go to these places down dark alleys, surrounded by shady characters and you can buy them. -- Chris Elmquist
Re: using new technology on old machines
On Tue, 16 Jun 2015, Mark J. Blair wrote: On Jun 16, 2015, at 08:19, geneb ge...@deltasoft.com wrote: On Tue, 16 Jun 2015, Noel Chiappa wrote: I wish there was some _easy_ way to lay in a stock of the most common TTL IC's - e.g. some kind of kit one could buy - but alas, I don't know of any. (Hence my dream of finding and acquiring someone else's collection! :-) Suggestions for the source of such a good diversified 'starter kit' welcome... How about this: http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_84961_-1 Very nice! I might just order one of those. They also offer 4000 series, transistor, resistor, and capacitor collections. g. -- Proud owner of F-15C 80-0007 http://www.f15sim.com - The only one of its kind. http://www.diy-cockpits.org/coll - Go Collimated or Go Home. Some people collect things for a hobby. Geeks collect hobbies. ScarletDME - The red hot Data Management Environment A Multi-Value database for the masses, not the classes. http://scarlet.deltasoft.com - Get it _today_!
Re: using new technology on old machines
On Tue, Jun 16, 2015 at 01:54:56PM +, tony duell wrote: I find it odd that people want to have a lights-and-switches panel, but are prepared to totally adulterate the hardware of the machine that drives it. Are you honestly suggesting that I should rebuild a PDP-11/70 from things I have in my partsbin? 'cause that is what it sounds like. /P
Re: O/S design implementation - was Re: FPGA tricks - Re: using new technology on old machines
On Jun 16, 2015, at 2:49 AM, ben bfranc...@jetnet.ab.ca wrote: ... Since the computer I designed is a *small* computer, 8 16 bit operating systems is what I am looking at for ideas. This is a 18 bit cpu with the concept, byte access of memory needs true 18 bit addressing and 16 bits is bit small for general 1970's data. Think of it as a something like a 9 bit 6800 cpu. If you’re looking at 1960s designs, you should be fine even if the machine had wider words. By the standards of that era, any modern computer (probably including the one in your microwave oven) is *large*. For example, the THE OS memory footprint is about 16k words (48k bytes), and that includes not just what we think of as a kernel but also all the device drivers and a bunch of language support library code. Other designs from that era are smaller still. paul
RE: using new technology on old machines
I find it odd that people want to have a lights-and-switches panel, but are prepared to totally adulterate the hardware of the machine that drives it. Are you honestly suggesting that I should rebuild a PDP-11/70 from things I have in my partsbin? You have to admit it would be an interesting and educational project :-) 'cause that is what it sounds like. No, not really. If you have a front panel from an otherwise non-existant machine then it makes sense to drive it any way you can. I was thinking more of the PDP12 that started this. -tony
Re: using new technology on old machines
On Tue, Jun 16, 2015 at 03:58:51PM +, tony duell wrote: Are you honestly suggesting that I should rebuild a PDP-11/70 from things I have in my partsbin? You have to admit it would be an interesting and educational project :-) Oh, very much! Then we could have a discussion about using modern switching power supplies ot not ;-) /P
Re: using new technology on old machines. Was: PDP-12 Restoration at the RICM
On Monday (06/15/2015 at 10:14PM -0700), Mark J. Blair wrote: On Jun 15, 2015, at 21:59, tony duell a...@p850ug1.demon.co.uk wrote: Even though there are at least 4 different USB connectors Ok, you got me there! When I was working for a GPS startup, I used mini-B on everything I designed with USB (always devices, never hosts, and no need for USB OTG). Then we got bought by a cell phone company and now everything's a godawful mix of mini-B and micro-B, with OTG thrown in there, too. Grrr! I'm going straight to hell because I recently participated in a customer design where they wanted to change the USB function on a device we designed for them from host mode to device mode but they didn't want to change the connector on the box. So, now you have to use a Type A to Type A cable to connect this box to your computer. That is just really, really messed up and I honestly tried to make it right but it was like pushing a rope. I hope my friends will visit me in prison. Chris -- Chris Elmquist
RE: using new technology on old machines
It's also that this is the 'classic computers' list. To me, classic computing means rather more than just the hardware. It also covers the design and construction methods, technology and so on. And there seems to be precious little of that in a modern microcontroller acting as a clock oscillator. There isn't., but some-times we have to compromise, and sometimes we choose to compromise. I looked at the circuit of the M484 and I might not have the parts in the parts box... I assume you mean M452 here, I can't find a reference to M484. I suspect many of the parts are not that critical. .. its also a nasty hybrid design with DC biased NPN and PNP transistors. I find it ugly and can see it being a pig to debug, though it simulates fine in LTspice... I didn't find it that hard to basically understand in my head. After all, there are only 4 transistors, and 2 of those are just an output buffer. Quite why having both NPN and PNP transistors makes it harder to understand I do not know. I will leave the flames about Spice and simulation packages in general for another day. -tony
Re: O/S design implementation - was Re: FPGA tricks - Re: using new technology on old machines
On Jun 15, 2015, at 7:10 PM, Sean Caron sca...@umich.edu wrote: ... 4. Madnick/Donovan Operating Systems or Donovan's Systems Programming ... were, I imagine, the canon of the 70s and early 80s ... these are written mostly with the S/360 in mind … If it’s written with 360 operating systems in mind, I’d steer clear. I don’t know of much in the way of valuable OS design principles to be found there (except perhaps the lessons reported in “the mythical man month” or in Tom Watson’s famous anecdote about the size of the CDC 6600 development effort). paul
Re: using new technology on old machines
On Tue, 16 Jun 2015, Noel Chiappa wrote: I wish there was some _easy_ way to lay in a stock of the most common TTL IC's - e.g. some kind of kit one could buy - but alas, I don't know of any. (Hence my dream of finding and acquiring someone else's collection! :-) Suggestions for the source of such a good diversified 'starter kit' welcome... How about this: http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_84961_-1 g. -- Proud owner of F-15C 80-0007 http://www.f15sim.com - The only one of its kind. http://www.diy-cockpits.org/coll - Go Collimated or Go Home. Some people collect things for a hobby. Geeks collect hobbies. ScarletDME - The red hot Data Management Environment A Multi-Value database for the masses, not the classes. http://scarlet.deltasoft.com - Get it _today_!
Re: O/S design implementation - was Re: FPGA tricks - Re: using new technology on old machines
On 6/16/2015 8:56 AM, Paul Koning wrote: On Jun 16, 2015, at 2:49 AM, ben bfranc...@jetnet.ab.ca wrote: ... Since the computer I designed is a *small* computer, 8 16 bit operating systems is what I am looking at for ideas. This is a 18 bit cpu with the concept, byte access of memory needs true 18 bit addressing and 16 bits is bit small for general 1970's data. Think of it as a something like a 9 bit 6800 cpu. If you’re looking at 1960s designs, you should be fine even if the machine had wider words. By the standards of that era, any modern computer (probably including the one in your microwave oven) is *large*. For example, the THE OS memory footprint is about 16k words (48k bytes), and that includes not just what we think of as a kernel but also all the device drivers and a bunch of language support library code. Other designs from that era are smaller still. There is *NO* computer in my MICROWAVE! I have the good kind! ( I need to fix the the defrost and half power settings someday). Timer dings when food is cooked. paul 16K words seems right, for that era as core was swapped in and out to run system and program threads. Since TIME SHARING was the big development feature of that era, I am ignoring most main frame operating systems. Single user with small memory and disk I/O as similar to the mid 1970's is my goal. But this is all I have to say, as I want stick to real hardware on this list. Ben.
Re: using new technology on old machines
On 6/16/2015 9:58 AM, Pontus Pihlgren wrote: On Tue, Jun 16, 2015 at 01:54:56PM +, tony duell wrote: I find it odd that people want to have a lights-and-switches panel, but are prepared to totally adulterate the hardware of the machine that drives it. Are you honestly suggesting that I should rebuild a PDP-11/70 from things I have in my partsbin? 'cause that is what it sounds like. /P I was more expecting a PDP 8 :) Ben.
RE: using new technology on old machines. Was: PDP-12 Restoration at the RICM
On Tue, 16 Jun 2015, tony duell wrote: Actually, IIRC a USB A male-female cable violates the spec... The spec forbids extending the cable further? Or should the spec forbid absolutely any cable, with absolutely any USB connector on either end?
Re: using new technology on old machines
On Jun 16, 2015, at 4:05 PM, Kyle Owen kylevo...@gmail.com wrote: On Jun 16, 2015 3:43 PM, tony duell a...@p850ug1.demon.co.uk wrote: Actually, no. That honour goes to the PSU in a Zenith MDA monitor which as I said 'combines the efficiency of a linear with the reliability of a switcher'. The design (if you can call it that) of this PSU is to rectify the mains, feed it into a free-running chopper circuit, then a transformer. The output of that is half-wave (!) rectified giving about 18V DC. Note the chopper free-runs, so there is no regulation applied at this point. That 18V is then fed to a discrete-transistor linear regulator. Maybe someone learned how high voltage supplies for TV sets work (from the sweep voltage) and decided to apply that. It does sound like someone with too little knowledge or ability for the job. And that's not the end of the 'curious' design. As you know, a linear regualtor compares the output voltage of the supply with a reference votlage. That reference voltage is typically produced by a zener diode. Not in this monitor. It uses the drop across the power-on LED. Which means it is important to use a green LED. Another colour, with a different Vf, and the PSU output is wrong. I would love to have a copy of that schematic for an Engineering Wall of Shame. Seriously, that is the strangest supply design I've ever heard. That doesn’t seem so bad. Diodes have well defined forward drops, and it certainly is not unprecedented to use the forward drop of, say, a plain silicon rectifier as a reference, or as a fixed drop where that value is needed. The same goes for LEDs. Of course it depends on the material (band gap voltage) which means it depends on the color. While this particular thing is a bit odd, it seems like a clever optimization, eliminating a part by having one that was wanted anyway do two jobs. Sort of the hardware equivalent of reusing a instruction as a constant — which I understand was done in some PDP-8 device drivers (the DECtape driver comes to mind). paul
Re: using new technology on old machines
On Wed, Jun 17, 2015 at 1:54 AM, tony duell a...@p850ug1.demon.co.uk wrote: It's also that this is the 'classic computers' list. To me, classic computing means rather more than just the hardware. It also covers the design and construction methods, technology and so on. DING. Staying slightly on-topic, working on serious wire-wrap backplanes can get a bit hairy. We probably all have hand-wrapping tools, and can do the occasional repair or patch as required. But... 'remanufacturing' has become part of preservation movements in general; 'preservation/re-creation' might be a better name. The ultimate example of this might be from the railway world. A famous class of British steam locomotives - the A1 Pacific - had become extinct; all were scrapped before railway preservation really became a Big Thing. So, enough enthusiasts got together and they *built* one. From scratch, from raw metal: http://www.a1steam.com There are various bits of DEC hardware that are extinct, or in critically short supply. I would love to have a TC15 DECtape controller for my pdp-15s; fat chance of ever finding one. Ditto for memory for my KL10. Oh sure, we can make modern functionally equivalent replacements, like Guy S, LCM etc, have done. But it's not the same... DEC backplanes were largely wire-wrapped by machine; I've seen pictures. If the interest was there, it should be possible to restore or re-create the machines used by DEC to manufacture backplanes. From there, it's a relatively small step to source, or manufacture new batches of, the modules etc. needed to populate them Has this ever been seriously considered, or mooted as a possible co-operative venture for a group of us? Mike http://www.corestore.org 'No greater love hath a man than he lay down his life for his brother. Not for millions, not for glory, not for fame. For one person, in the dark, where no one will ever know or see.'
Re: using new technology on old machines
On Jun 16, 2015, at 17:52 , Mike Ross tmfdm...@gmail.com wrote: 'remanufacturing' has become part of preservation movements in general; [...] Has this ever been seriously considered, or mooted as a possible co-operative venture for a group of us? On this topic, I'm particularly curious about remanufacturing of consumables such as magnetic media, printer ribbons, etc. Not only are supplies of unused consumables monotonically decreasing, but even remaining ones are succumbing to shelf rot (case in point: TU58 cartridges, and particularly their drive belts). In many cases, it may not be strictly necessary to manufacture the entire item. For a TU58 cartridge, the baseplate, case, reels, etc. may be quite usable. The tape probably needs to be replaced, but maybe a particular formulation of common audio tape could be used instead of manufacturing tape from scratch. The belts would certainly need to be manufactured from scratch. In other cases, even where the item needs to be manufactured from scratch, might it be acceptable to use modern methods to manufacture authentic-ish replacement consumables? If somebody figured out how to create suitable magnetic material and binder for floppy disk media and apply it to mylar sheets, for example, maybe a laser cutter could be used to cut out various kinds of blanks (5.25, 8, soft-sectored, various hard-sectored configurations) without the tooling cost of punching dies that would make more sense for mass production? Would the mentioned automatic wire-wrapping machine need to be recreated in a period-correct manner, or would it be acceptable to make one using modern expedient hardware in order to use it to create new authentic reproductions? What sort of concessions could we accept for the lack of authentic components to be used? In the case of a locomotive, there are an awful lots of parts that could be authentically remanufactured in a regular machine shop (obviously, large forgings and the like would be more challenging!). But in the case of a computer using particular no-longer-manufactured semiconductor components, the thought of bringing up a suitable semiconductor fab to build those components would be economically unrealistic. -- Mark J. Blair, NF6X n...@nf6x.net http://www.nf6x.net/
RE: using new technology on old machines
[M452] that the original appears to use a 2k 10-turn pot, and a 7440 output buffer, neither of which are in my rather extensive junk box. In fact the 7440 are rather rare, and I see the cheapest I can get them for is around $4.00 each. True. But you don't need either to build and test the oscillator circuit. The 7440 is an output buffer, if you want to build a test version of the entire module you could stick a '20 there or just about any other TTL inverting gate. But I was thinking of just testing the oscillator part which is Q1 and Q2 (again the other 2 transistors are buffers) The preset clearly sets the frequency. You could build the oscillator with say a 1k resistor there at least to put a 'scope on various points to understand how it works. I am really used to RF circuits so am puzzled there is no inductor. It kind of looks like a Darlington Pair but it isn't. RC oscillators have been around since the 1930s. I will leave the flames about Spice and simulation packages in general for another day. You are touchy. Would it help if I used the original Spice2 written in Fortran IV. It still works. Sadly I don't have a real mainframe but have to use Hercules to run it OK, I sort-of forgot the smiley, but only sort-of. The problem is that people try to understand a circuit by throwing it on the simulator and really don't understand what is going on at all (this assumes the simulator gets it right which is not always the case). I prefer to think about it. work out how the capacitor (there is only one!) charges and discharges, since that must be the key to the oscillations. -tony
Re: O/S design implementation - was Re: FPGA tricks - Re: using new technology on old machines
I thought I'd take a quick spin through the operating systems section of my library now that I'm at home just to give you some titles that you might want to check out. 1. Toby mentions Tanenbaum's Minix book and that's a fairly canonical text ... there is a lot of great information in there but IMO some parts can be a little opaque and overly verbose ... it can be nice to have some supplementary sources; see (2) :O 2. For more illumination on UNIX, I find both Maurice Bach's Design of the UNIX Operating System and McKusick's 4.4 BSD book to be well-written. 3. There's a design example (source with walkthrough) for a simple task scheduler for the PDP-11 in Eckhouse's Minicomputer Systems: Organization and Programming (PDP-11 edition). 4. Madnick/Donovan Operating Systems or Donovan's Systems Programming ... were, I imagine, the canon of the 70s and early 80s ... these are written mostly with the S/360 in mind ... 5. For something maybe less academic and a bit more practical, look for the MMURTL book; I believe the title is Developing your own 32-bit Operating System by Burgess ... neat book ... I've leafed through it but I down own a copy. Platform is i386. 6. There are also a lot of practicals on Merrill Press that are very good i.e. The 68000 Micrporocessor by Antonakos ... that will demonstrate the implementation of a basic ROM monitor from scratch ... I found these books very illuminating and I think they can be a good bridge between the more theoretical treatment given in a lot of textbooks and the actual nitty-gritty of writing some code on bare-metal hardware. You can pick up a used copy of any of these books for a buck or two on the used market; that's hard to beat. That's pretty much all I got ... always looking for interesting books on this topic contemporary or historic; if anyone else has titles to share that they could recommend, I'm always happy to hear. Best, Sean On Mon, Jun 15, 2015 at 6:42 PM, Toby Thain t...@telegraphics.com.au wrote: On 2015-06-15 12:18 PM, ben wrote: On 6/15/2015 9:08 AM, Toby Thain wrote: On 2015-06-15 9:35 AM, Dave G4UGM wrote: I don't think it is over kill. If you want over kill try this:- https://www.youtube.com/watch?v=ALXax3Gydl8 and FPGA implementation of the Baby or SSEM which had 32x32 bits of RAM. The implementation uses around 1% of the Spartan 3E 1200K gates, and that includes the logic to generate the VGA which is around 50% of the circuit. I expect to get it on a 100K gate chip but that’s still over-kill. Speaking of VGA, you might like this: http://www.fpgarelated.com/showarticle/42.php --Toby But alas the software does *not* support the older chips. You want to make a mod 5 years down the road, sorry we do not support that model any more. TTL needs to be stock piled now for the next +50 years. I finally got 18 bit FPGA computer (DE1) design I like, that is early 70's speed. 1.5 us core. What I am having problems is finding a good book on Operating Systems from that Era that is online, any one know a good book? I have software that I need to write. I think Tanenbaum should be fine? A lot of it is fairly timeless. https://archive.org/details/OperatingSystemsDesignImplementation --Toby Ben.
Re: O/S design implementation - was Re: FPGA tricks - Re: using new technology on old machines
On 6/15/2015 5:10 PM, Sean Caron wrote: I thought I'd take a quick spin through the operating systems section of my library now that I'm at home just to give you some titles that you might want to check out. 1. Toby mentions Tanenbaum's Minix book and that's a fairly canonical text ... there is a lot of great information in there but IMO some parts can be a little opaque and overly verbose ... it can be nice to have some supplementary sources; see (2) :O 2. For more illumination on UNIX, I find both Maurice Bach's Design of the UNIX Operating System and McKusick's 4.4 BSD book to be well-written. 3. There's a design example (source with walkthrough) for a simple task scheduler for the PDP-11 in Eckhouse's Minicomputer Systems: Organization and Programming (PDP-11 edition). 4. Madnick/Donovan Operating Systems or Donovan's Systems Programming ... were, I imagine, the canon of the 70s and early 80s ... these are written mostly with the S/360 in mind ... 5. For something maybe less academic and a bit more practical, look for the MMURTL book; I believe the title is Developing your own 32-bit Operating System by Burgess ... neat book ... I've leafed through it but I down own a copy. Platform is i386. 6. There are also a lot of practicals on Merrill Press that are very good i.e. The 68000 Micrporocessor by Antonakos ... that will demonstrate the implementation of a basic ROM monitor from scratch ... I found these books very illuminating and I think they can be a good bridge between the more theoretical treatment given in a lot of textbooks and the actual nitty-gritty of writing some code on bare-metal hardware. You can pick up a used copy of any of these books for a buck or two on the used market; that's hard to beat. That's pretty much all I got ... always looking for interesting books on this topic contemporary or historic; if anyone else has titles to share that they could recommend, I'm always happy to hear. Best, Sean Since the computer I designed is a *small* computer, 8 16 bit operating systems is what I am looking at for ideas. This is a 18 bit cpu with the concept, byte access of memory needs true 18 bit addressing and 16 bits is bit small for general 1970's data. Think of it as a something like a 9 bit 6800 cpu. Ben.
Re: using new technology on old machines. Was: PDP-12 Restoration at the RICM
On Tue, Jun 16, 2015 at 04:32:23AM +, tony duell wrote: Oh come on. You yourself said you are here to learn. This module is hardly complicatated. Well, you got me there :) /P
Re: using new technology on old machines. Was: PDP-12 Restoration at the RICM
On Tue, Jun 16, 2015 at 04:28:16AM +, tony duell wrote: I am of course counting all the transistors inside that chip. Well, that was obvious. But it raises an interesting point, today you can cram a whole computer in the footprint of the simplest DIP carrier. For the same price point and same reliablity. Is it then overkill if you choose to use thousands of those transistor over using just 10 ? Similar to Mark's example of using just the first bytes of an SD card with gigabytes of storage. This is one of my main dislikes with USB. It is so complicated that you have to use a microcontroller. Unlike any of the more sane interfaces that you can implement with simple logic if you want to. I completely agree, I detest USB for various reasons. However consider this: As I said, I have used the Teensy to interface an old 11/70 front panel with simh. One possibility I've considered is to let the Teensy present itself as USB mass storage when first attached to a PC. On this mass storage I would put a special version of simh and 11/70 system images. When this version of simh is run, it will instruct the Teensy to present itself as the front panel interface instead. So, I can bring my 11/70 front panel to any friend with a suitable computer and show him/her the ropes :) Admittedly, the Teensy doesn't have enough storage for this, but it shows the flexibilty of USB coupled with a microcontroller. /P
Re: using new technology on old machines. Was: PDP-12 Restoration at the RICM
While I agree that as long as things can be restored it's not a real problem, I'm surprised that not more people consider it a serious overkill. We're talking about putting in a rather complex computer to generate a baud rate. Are people really that handicapped when it comes to building hardware nowadays? Are people aware how easy baud generators are? We're essentially talking about a clock, which can be found as a component (various oscillators), and then dividing it. There used to be chips around which did that part, and I would expect it to not be that hard to find some if you looked today. Many UARTs even comes with a clock divider built in. And that is it. When I build various Z80 systems, I usually had a Z80 CTC included, which I used for generating the baud rates. Johnny On 2015-06-15 02:52, Joe Lenox wrote: I also think it is in the spirit of the computer - using what is available to fix a problem at hand. I think the arduino was overkill when an attiny (smaller, easier to hide) would probably serve just as well. If you have the ttl logic bits lying around and know how to use them, fine. Still would probably need debugging. On Jun 14, 2015 2:41 PM, Simon Claessen sim...@dds.nl wrote: as long as it is done in a way that it can be restored to its original, i have no problems in using newer technology in older machines. we have a alix sbc build into our tek 4002a for demonstrational purpouses, all done without damaging or altering the original machine. On 14-06-15 17:25, tony duell wrote: The ripple on the power supplies is still going lower as we put more run time on the system. The power supplies are now within spec. Capacitors reforming naturally? Warren made an Arduino based programmable baud rate generator that works for both serial ports. After some debugging, it works nicely. I am sorry, but I find that obscene!. To use more components than the rest of the machine (probably) just for the baud rate clock is ridiculous. IMHO if you are going to modify a vintage machine, particularly one as rare as a PDP12, you should use the components that were available at the time. It's not as if a programmable buad rate generator is hard to make from TTL either. In fact given the Arduino thing needed 'some debugging' it might well have taken less time to do it in hardware. -tony -- Met vriendelijke Groet, Simon Claessen drukknop.nl -- Johnny Billquist || I'm on a bus || on a psychedelic trip email: b...@softjar.se || Reading murder books pdp is alive! || tryin' to stay hip - B. Idol
Re: using new technology on old machines. Was: PDP-12 Restoration at the RICM
On Mon, Jun 15, 2015 at 11:52:28AM +0200, Johnny Billquist wrote: We're talking about putting in a rather complex computer to generate a baud rate. Are people really that handicapped when it comes to building hardware nowadays? Speaking for myself, yes. I have a Teensy 2.0 lying at my desk, it's Arduino compatible. I have the development environemnt set up, a small solderless breadboard and proper power supply. I could probably whip up the C-code for a flicking pin on and off in the correct pace in very little time. Now, if the alternative is reading up on crystals, oscillators, dividers and related support chips, figure out where to buy and then wait for the parts to ship, which option do you think I will choose? Of course, I think it's overkill and anachronistic and I'd rather use the Teensy for something else, so I'd probably read up and do it right too. /P
Re: using new technology on old machines. Was: PDP-12 Restoration at the RICM
Indeed, you use what is at hand and what you are comfortable with. /P On Sun, Jun 14, 2015 at 09:41:42PM +0200, Simon Claessen wrote: as long as it is done in a way that it can be restored to its original, i have no problems in using newer technology in older machines. we have a alix sbc build into our tek 4002a for demonstrational purpouses, all done without damaging or altering the original machine. On 14-06-15 17:25, tony duell wrote: The ripple on the power supplies is still going lower as we put more run time on the system. The power supplies are now within spec. Capacitors reforming naturally? Warren made an Arduino based programmable baud rate generator that works for both serial ports. After some debugging, it works nicely. I am sorry, but I find that obscene!. To use more components than the rest of the machine (probably) just for the baud rate clock is ridiculous. IMHO if you are going to modify a vintage machine, particularly one as rare as a PDP12, you should use the components that were available at the time. It's not as if a programmable buad rate generator is hard to make from TTL either. In fact given the Arduino thing needed 'some debugging' it might well have taken less time to do it in hardware. -tony -- Met vriendelijke Groet, Simon Claessen drukknop.nl
using new technology on old machines. Was: PDP-12 Restoration at the RICM
as long as it is done in a way that it can be restored to its original, i have no problems in using newer technology in older machines. we have a alix sbc build into our tek 4002a for demonstrational purpouses, all done without damaging or altering the original machine. On 14-06-15 17:25, tony duell wrote: The ripple on the power supplies is still going lower as we put more run time on the system. The power supplies are now within spec. Capacitors reforming naturally? Warren made an Arduino based programmable baud rate generator that works for both serial ports. After some debugging, it works nicely. I am sorry, but I find that obscene!. To use more components than the rest of the machine (probably) just for the baud rate clock is ridiculous. IMHO if you are going to modify a vintage machine, particularly one as rare as a PDP12, you should use the components that were available at the time. It's not as if a programmable buad rate generator is hard to make from TTL either. In fact given the Arduino thing needed 'some debugging' it might well have taken less time to do it in hardware. -tony -- Met vriendelijke Groet, Simon Claessen drukknop.nl
Re: using new technology on old machines. Was: PDP-12 Restoration at the RICM
I also think it is in the spirit of the computer - using what is available to fix a problem at hand. I think the arduino was overkill when an attiny (smaller, easier to hide) would probably serve just as well. If you have the ttl logic bits lying around and know how to use them, fine. Still would probably need debugging. On Jun 14, 2015 2:41 PM, Simon Claessen sim...@dds.nl wrote: as long as it is done in a way that it can be restored to its original, i have no problems in using newer technology in older machines. we have a alix sbc build into our tek 4002a for demonstrational purpouses, all done without damaging or altering the original machine. On 14-06-15 17:25, tony duell wrote: The ripple on the power supplies is still going lower as we put more run time on the system. The power supplies are now within spec. Capacitors reforming naturally? Warren made an Arduino based programmable baud rate generator that works for both serial ports. After some debugging, it works nicely. I am sorry, but I find that obscene!. To use more components than the rest of the machine (probably) just for the baud rate clock is ridiculous. IMHO if you are going to modify a vintage machine, particularly one as rare as a PDP12, you should use the components that were available at the time. It's not as if a programmable buad rate generator is hard to make from TTL either. In fact given the Arduino thing needed 'some debugging' it might well have taken less time to do it in hardware. -tony -- Met vriendelijke Groet, Simon Claessen drukknop.nl
RE: using new technology on old machines. Was: PDP-12 Restoration at the RICM
I don't think it is over kill. If you want over kill try this:- https://www.youtube.com/watch?v=ALXax3Gydl8 and FPGA implementation of the Baby or SSEM which had 32x32 bits of RAM. The implementation uses around 1% of the Spartan 3E 1200K gates, and that includes the logic to generate the VGA which is around 50% of the circuit. I expect to get it on a 100K gate chip but that’s still over-kill. I am also aware how HARD baud rate generator chips are. Firstly you need to know the multiplier, and then you need a crystal that can easily be divided. I looked on E-Bay UK and the cheapest dedicated baud rate generator was 10x the price of a Arduino Nano. Then I would need a crystal and the other bits to make the generator. I would expect the chip count on a dedicated baud rate generator board to exceed that of the Nano. Of course it is not original, but an authentic board would only use SSI TTL and where would one find that easily. I personally think it is an appropriate cludge that allows de-bugging to continue and gives you time to work out what the best long term solution would be. Dave -Original Message- From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Johnny Billquist Sent: 15 June 2015 10:52 To: cctalk@classiccmp.org Subject: Re: using new technology on old machines. Was: PDP-12 Restoration at the RICM While I agree that as long as things can be restored it's not a real problem, I'm surprised that not more people consider it a serious overkill. We're talking about putting in a rather complex computer to generate a baud rate. Are people really that handicapped when it comes to building hardware nowadays? Are people aware how easy baud generators are? We're essentially talking about a clock, which can be found as a component (various oscillators), and then dividing it. There used to be chips around which did that part, and I would expect it to not be that hard to find some if you looked today. Many UARTs even comes with a clock divider built in. And that is it. When I build various Z80 systems, I usually had a Z80 CTC included, which I used for generating the baud rates. Johnny On 2015-06-15 02:52, Joe Lenox wrote: I also think it is in the spirit of the computer - using what is available to fix a problem at hand. I think the arduino was overkill when an attiny (smaller, easier to hide) would probably serve just as well. If you have the ttl logic bits lying around and know how to use them, fine. Still would probably need debugging. On Jun 14, 2015 2:41 PM, Simon Claessen sim...@dds.nl wrote: as long as it is done in a way that it can be restored to its original, i have no problems in using newer technology in older machines. we have a alix sbc build into our tek 4002a for demonstrational purpouses, all done without damaging or altering the original machine. On 14-06-15 17:25, tony duell wrote: The ripple on the power supplies is still going lower as we put more run time on the system. The power supplies are now within spec. Capacitors reforming naturally? Warren made an Arduino based programmable baud rate generator that works for both serial ports. After some debugging, it works nicely. I am sorry, but I find that obscene!. To use more components than the rest of the machine (probably) just for the baud rate clock is ridiculous. IMHO if you are going to modify a vintage machine, particularly one as rare as a PDP12, you should use the components that were available at the time. It's not as if a programmable buad rate generator is hard to make from TTL either. In fact given the Arduino thing needed 'some debugging' it might well have taken less time to do it in hardware. -tony -- Met vriendelijke Groet, Simon Claessen drukknop.nl -- Johnny Billquist || I'm on a bus || on a psychedelic trip email: b...@softjar.se || Reading murder books pdp is alive! || tryin' to stay hip - B. Idol
Re: using new technology on old machines. Was: PDP-12 Restoration at the RICM
We're talking about putting in a rather complex computer to generate a baud rate. Are people really that handicapped when it comes to building hardware nowadays? Speaking as someone who didn't do that, but might well have - it's not a question of handicapped; it's a question of convenience, ease of use, and suchlike. Yes, I know how to build a BRG in hardware. I've even done it, more or less. But if I want something fast, and I have a small SOC handy, I may well use it: it's a lot easier to change the generated frequency in more-or-less arbitrary ways (ie, other than just picking a different tap off a divider chain), and it's quite possible the SOC is at readier hand than the oscillator and divider. Of course, if it's going to be there for more than the short term, I probably will replace it once I've settled on a frequency. But initially? Sure, I'll go with the complex way, for convenience and flexibility. I'm also likely to fire up a calculator program on a desktop computer to add two five-digit numbers rather than reaching for pencil and paper or a dedicated calculator. Even though I'm hardly incapable of using either of the latter. When the more powerful tool is handy and its use carries no sigificant downside, I see nothing wrong with overkill. /~\ The ASCII Mouse \ / Ribbon Campaign X Against HTMLmo...@rodents-montreal.org / \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B
Re: using new technology on old machines. Was: PDP-12 Restoration at the RICM
On Jun 15, 2015, at 3:06 AM, Pontus Pihlgren pon...@update.uu.se wrote: On Mon, Jun 15, 2015 at 11:52:28AM +0200, Johnny Billquist wrote: We're talking about putting in a rather complex computer to generate a baud rate. Are people really that handicapped when it comes to building hardware nowadays? Speaking for myself, yes. I have a Teensy 2.0 lying at my desk, it's Arduino compatible. I have the development environemnt set up, a small solderless breadboard and proper power supply. I could probably whip up the C-code for a flicking pin on and off in the correct pace in very little time. Now, if the alternative is reading up on crystals, oscillators, dividers and related support chips, figure out where to buy and then wait for the parts to ship, which option do you think I will choose? Agreed. I really love the modern microcontrollers like the Arduino and tiny embedded computers with GPIO like the Raspberry Pi or Galileo because they make it so incredibly easy to turn a hardware problem into a software problem. And writing software is super easy, even if you’re not an expert. You can just keep trying another solution over and over and all you have to do is push a few keys on your keyboard. -- Follow me on twitter: @FozzTexx Check out my blog: http://insentricity.com
Re: O/S design implementation - was Re: FPGA tricks - Re: using new technology on old machines
On 2015-06-15 8:09 PM, ben wrote: On 6/15/2015 4:42 PM, Toby Thain wrote: I think Tanenbaum should be fine? A lot of it is fairly timeless. The latest version is *useless*. The racoons on the cover tells alot. I figured, although I haven't seen it. My copy is 1987. https://archive.org/details/OperatingSystemsDesignImplementation I was looking all over for this version, online. Glad I could help. --Toby Ben.
RE: using new technology on old machines. Was: PDP-12 Restoration at the RICM
Why not do it properly first time? What is the rush in bringing up a classic computer? And for a test, use the TTL pulse generator you have on your bench. I don't have one. I have a lot of test equipment, but mostly for RF work. If I needed to generate TTL pulses, I'd probably pull out a microcontroller development board of some sort, because that's what I have sitting around. And you don't have any NPN transistors around? With one you could buffer the output of your sig-gen to TTL levels. No, I have neither 2N3904s nor NE555s in my spares. I could replace an M1 Carbine trigger spring on the spot, Amazing Those are about the most common components around. I think I buy 2N3904s in lots of 1000, I use so many of them [...] capabilities, so not everybody will do things the same way that you do. Should I criticize you for not having SAE FWIW I do have Bristol spline keys here. Needs for working on IBM and Friden machines for a start. FWIW, this is not the miltary or firearms list, so I wouldn't expect people to necessarily have the equipment and spares for such things (if you do, fine). It is the classiccmp list, where some people, including your good self restore the actual old machines. And yes, I think it is is reasonable to assume they will have access to common (very common) electronic components. -tony
RE: using new technology on old machines. Was: PDP-12 Restoration at the RICM
I am very worried that people would rather use a microcontroller than change a couple of passives. Can't anyone read a schematic and think Nope. I didn't know this hobby required a degree in electrical engineering. Well it had better not. I don't have one By your criteria a lot of the rare stuf behind me would be in the dumpster because no-one qualified was arround. Oh come on. You yourself said you are here to learn. This module is hardly complicatated. OK, it is not obvious what some of the waveforms are (which is a good reason to put that board on the bench -- it will run on its own -- and probe it with a 'scope. Being an oscillator, all the waveforms are repetitive so _any_ 'scope will do), but it is farily clear that it is an RC oscillator and that the time constant of a particular RC network is going to have an effect on the output frequency. So you change the capacitor and probe with the 'scope again. And so on. -tony /P
Re: using new technology on old machines. Was: PDP-12 Restoration at the RICM
On Jun 15, 2015, at 21:28, tony duell a...@p850ug1.demon.co.uk wrote: As am I. I've learnt a heck of a lot since I started (there is a common myth that there is something magic about a processor. This hobby has taught me to understand quite a few at the gate level). And the day I stop learning is the day I am in a pine box. In my opinion, the magic is inside the transistor. Once you bottle enough magic to make a good transistor, the rest is pretty straightforward. :) As an aside, I am not overly enamoured by the RPi. I think there are possibly better alternatives like the Beagleboards (?) which I need to investigte. Shockingly, I agree with you! The RPi is neat for what it is, but I have a mental hangup on openness, which the Beaglebone Black has more of (i.e., I think I could buy the main chip on it from DigiKey, unlike the Broadcom chip on the RPi. Not that I'm eager to route my own SDRAM bus... that's actually kind of hard, particularly with the open-source PCB tools I use for home projects). The BeagleBone also has lots more delicious IOs. This is one of my main dislikes with USB. It is so complicated that you have to use a microcontroller. Unlike any of the more sane interfaces that you can implement with simple logic if you want to. I have a love/hate relationship with USB. I liked moving away from having to figure out which way the danged plugs were wired at both ends for any given pair of devices. But on the other hand, a UART is dirt simple to implement, and I still use them for debug ports even on vastly complex FPGA-based stuff. I don't see async serial dying off any time soon. -- Mark J. Blair, NF6X n...@nf6x.net http://www.nf6x.net/
RE: using new technology on old machines
But if you are going to repair/restore something then IMHO it makes a lot of sense to have common spares around. Agreed! But you generally tend to accumulate those spares *after* you have been involved in that particular True. I wil bet you didn't have firearm spares when you first started out either area for a while. Coming into it from scratch, you might not even know which parts you're most likely to need. And buying every common-ish part that you might need is an expensive proposition. That is also true. And it's not obvious what is common and it very much depends on the machine you are working on. If you fix 1980s home micros you probably have a few 6502 and Z80s on-hand, but they are not a lot of use in a PDP12. [...] extras. But I don't have a single 2N3904 in my junk box, because I don't think I've had to replace one in the last I use them all the time for LED drivers, etc 30 years, just based on the kinds of things I've been working on. So it's not my go-to part. Now, 10k resistors and 0.1uF ceramic caps... those things I use a lot. :) And to get back to that darn M452 module that started this, it is _precisely_ those sort of R's and C's you need to change its frequency! -tony -- Mark J. Blair, NF6X n...@nf6x.net http://www.nf6x.net/
Re: O/S design implementation - was Re: FPGA tricks - Re: using new technology on old machines
On 2015-06-15 9:11 PM, Paul Koning wrote: On Jun 15, 2015, at 8:09 PM, ben bfranc...@jetnet.ab.ca wrote: On 6/15/2015 4:42 PM, Toby Thain wrote: I think Tanenbaum should be fine? A lot of it is fairly timeless. The latest version is *useless*. The racoons on the cover tells alot. Or you could just read “The structure of the THE operating system” by E.W.Dijkstra, and follow its principles. Another essential read in this vein is Classic Operating Systems by Per Brinch Hansen[1], which is really an anthology of papers satisfyingly meaty. Perhaps like me you will be left feeling that we were so much better at this stuff 40 years ago. Also that many modern operating system ideas were invented much earlier than we might be tempted to think. (Multics is the usually cited case, but this book has dozens of other examples.) --Toby [1] http://www.amazon.ca/dp/038795113X paul
RE: using new technology on old machines. Was: PDP-12 Restoration at the RICM
Unfortunately I believe you. Use at least a thousand times more components than you need to. Actually it's just two, a Teensy and a usb cable. (Sorry, I couldn't resist). I am of course counting all the transistors inside that chip. How do you suggest I learn? I believe you had a father that got you of to a good start and perhaps you even took a few classes. My father was a chemist. He knew enough electronics to teach me things like ohm's law, but certainly not digital electronics. And I have never done any classes in electronics. I learnt by : 1) Reading every darn book I could find on electronics from the 1920s onwards 2) Experimenting. Soldering up circuits and finding out why they didn't work. Some of the better educational kits like the Philips EE series helped in my younger days, but alas you won't find those now. 3)Getting a minicomputer and investigating it. That means reading the printset, cliping on a logic analyser, etc. Certainly no excuse, but one of the main reasons I'm in this hobby is to learn! And boy have I learned a lot since I got started. I'm not at your As am I. I've learnt a heck of a lot since I started (there is a common myth that there is something magic about a processor. This hobby has taught me to understand quite a few at the gate level). And the day I stop learning is the day I am in a pine box. level yet.. but perhaps in a few years I'll be a tenth of the way there :) It might please you to hear that the Teensy I'm talking about is in a socket on a perfboard together with a handfull of 74165 and 74374 which I've wirewrapped in proper wirewrapping sockets. It will become a USB interface for my 11/70 front panel. The Teensy was the simplest/cheapest way to get a usb interface with lots of I/O pins. (Why usb? to get a connection to simh on one of those newfangled Pi-things) As an aside, I am not overly enamoured by the RPi. I think there are possibly better alternatives like the Beagleboards (?) which I need to investigte. This is one of my main dislikes with USB. It is so complicated that you have to use a microcontroller. Unlike any of the more sane interfaces that you can implement with simple logic if you want to. -tony
Re: using new technology on old machines
On Jun 15, 2015, at 21:40, tony duell a...@p850ug1.demon.co.uk wrote: Exactly. I don't do firearms at all (we have various IMHO ridiculous laws in the UK, but I do not want to start that debate) Sorry I even brought it up; I was just using it as an example of the different specializations that each person might wallow in. Guns, religion, politics and text editor preference are often too contentious to discuss in polite company. :) But if you are going to repair/restore something then IMHO it makes a lot of sense to have common spares around. Agreed! But you generally tend to accumulate those spares *after* you have been involved in that particular area for a while. Coming into it from scratch, you might not even know which parts you're most likely to need. And buying every common-ish part that you might need is an expensive proposition. But common TTL parts, transistors, etc are used in many machines, and if you are going to restore the real hardware you are (a) going to need them and (b) are going to need to now how they work so you can trace faults. Right. So coming in from scratch, you might buy a tube of 74LS00 instead of just the one that you need to fix one board, and so on for many other common parts. One method that works for me is that if you are buying a fairly cheap part, buy 10 of them and put the rest in stock. Or more than 10 if it is something really common. Agreed again! For example, the first time I had a Rifa paper-dielectric EMI filtering cap go incandescent on me (happened to be in a Tandy Model 12), I figured out the three or four kinds of much better poly film EMI filtering caps I'd need to replace them on sight in the Astec supplies that Tandy stuck in everything, and I bought lots of extras. But I don't have a single 2N3904 in my junk box, because I don't think I've had to replace one in the last 30 years, just based on the kinds of things I've been working on. So it's not my go-to part. Now, 10k resistors and 0.1uF ceramic caps... those things I use a lot. :) -- Mark J. Blair, NF6X n...@nf6x.net http://www.nf6x.net/
RE: using new technology on old machines. Was: PDP-12 Restoration at the RICM
I am very worried that people would rather use a microcontroller than change a couple of passives. Can't anyone read a schematic and think The exact same argument could be made for somebody using an NE555 instead of discrete transistors to blink an LED, or discrete transistors instead of vacuum tubes to blink a neon glow lamp. For that matter, I might call Err, to blink a neon glow lamp you use _one_ resistor and _one_ capacitor and make use of the difference between striking and maintaining voltages. But that is not the point. The original design for this M452 baud rate clock is an RC oscillator. One that can run at any reasonable frequency. When restoring a machine you should keep as much of the original design as possible. If you want to do a reversable change you should still change as little as possible. Since it appears you can change the buad rate just by changing a couple of passive components that's what IMHO you should do. -tony
RE: using new technology on old machines
I could replace an M1 Carbine trigger spring on the spot, or a HMMWV taillamp housing ... Should I criticize you for not having SAE grade 8 hardware on hand, or Bristo wrenches I think Tony's point was that someone who's into vintage computers ought to have a stock of suitable parts for them. So unless he's into older guns, or cars, were he not to have things like SAE 8 hardware around, that would be understandable - he doesn't do them. Exactly. I don't do firearms at all (we have various IMHO ridiculous laws in the UK, but I do not want to start that debate) and while I have repaired many cars in the past, I don't drive and don't, therefore, own a car of any type. But if you are going to repair/restore something then IMHO it makes a lot of sense to have common spares around. It's not like I am suggesting you should keep stocks of obscure HP custom microprocessors, or even things like 2901 bit-slice chips. But common TTL parts, transistors, etc are used in many machines, and if you are going to restore the real hardware you are (a) going to need them and (b) are going to need to now how they work so you can trace faults. Having said that, _I_ don't have 2N3904s nor NE555s around either! I do have a modest number of parts (e.g. 4164's, 40-ping Berg shells, .250 tab hardware, etc, etc) - a large enough collection that I just had to re-organize and add more parts holders (although that was mostly because I went berserk at the local Radio Shack in the 80% off sale). But it takes a long time to build up a really comprehensive collection of parts. One method that works for me is that if you are buying a fairly cheap part, buy 10 of them and put the rest in stock. Or more than 10 if it is something really common. -tony
Re: O/S design implementation - was Re: FPGA tricks - Re: using new technology on old machines
On 6/15/2015 7:58 PM, Toby Thain wrote: It's also one of the papers in the Brinch Hansen book cited earlier in the thread. (Google books: http://ur1.ca/mu61v ) Too much $$ for me at the moment (even online version). --Toby Ben.
Re: O/S design implementation - was Re: FPGA tricks - Re: using new technology on old machines
On 6/15/2015 7:55 PM, Toby Thain wrote: (The Structure of the THE-Multiprogramming System) Are you sure? http://ur1.ca/mu60x --Toby I saw that paper before. Ben.
Re: using new technology on old machines. Was: PDP-12 Restoration at the RICM
On Jun 15, 2015, at 21:59, tony duell a...@p850ug1.demon.co.uk wrote: Even though there are at least 4 different USB connectors Ok, you got me there! When I was working for a GPS startup, I used mini-B on everything I designed with USB (always devices, never hosts, and no need for USB OTG). Then we got bought by a cell phone company and now everything's a godawful mix of mini-B and micro-B, with OTG thrown in there, too. Grrr! IMHO USB got round the problem of null-modem cables by making them impossible. Which to me is not an improvement. I guess USB is OK when it works (like plugging in a memory stick) but a right pain to debug when it doesn't. And having read the standard there is much I dislike about it. Maybe this isn't the best time or place for this particular rant, but in my opinion, Windows' implementation of USB is fundamentally broken. It's a mouse, you stupid computer! You shouldn't need to spend a minute or more installing a new device driver for it! And you shouldn't need to install the driver yet again if I poke it in a different hole than I did last time! Every other *** OS on the planet is smart enough to say Oh, a mouse! I know how to use those! within a handful of milliseconds! (Take deep, cleansing breaths, Mark.) Ok, I feel better now. :) -- Mark J. Blair, NF6X n...@nf6x.net http://www.nf6x.net/
Re: using new technology on old machines. Was: PDP-12 Restoration at the RICM
On Jun 15, 2015, at 09:53 , tony duell a...@p850ug1.demon.co.uk wrote: I also think it is in the spirit of the computer - using what is available to fix a problem at hand. I think the arduino was overkill when an attiny (smaller, easier to hide) would probably serve just as well. Would you put plastic handles on a piecc of antique furniture? Would you make the seatboard for an antique longcase clock from MDF? Both are easily reversable, BTW. Sure! Temporarily and reversibly, of course, and I'd hope to replace them with proper stuff when possible. But to bring up an old computer system right now, I'll kludge in what I have available to get it running. In that respect, an Arduino-based baud rate generator could be considered test equipment rather than a component. If you have the ttl logic bits lying around and know how to use them, fine. Still would probably need debugging. FWIW I have made programmable dividers on a couple of occasions recently (one was a 100/120 flash-per-second stroboscope, the other was the transmitter half of a modem to talk to TDDs). Both of them worked first time. I guess it's just what I am used to. Exactly. And for somebody who doesn't already have a full stock of TTL parts on hand, a different solution may present itself. I play with gear from WWII military radios up through thoroughly modern electronics. When I work on a WWII radio, it might be considered cheating to poke at it with my Fluke multimeter, Tek DSO, HP spectrum analyzer or HP synthesized signal generator (the latter two of which are slaved to my GPS-disciplined frequency standard), but those are the tools I have on hand, so those are the tools that I use. -- Mark J. Blair, NF6X n...@nf6x.net http://www.nf6x.net/
RE: using new technology on old machines. Was: PDP-12 Restoration at the RICM
Would you put plastic handles on a piecc of antique furniture? Would you make the seatboard for an antique longcase clock from MDF? Both are easily reversable, BTW. Sure! Temporarily and reversibly, of course, and I'd hope to replace them with proper stuff when possible. But to bring up an old computer system right now, I'll kludge in what I have available to get it running. In that respect, an Arduino-based baud rate generator could be considered test equipment rather than a component. Ah, 'there's not the time to do it properly, but there is the time to do it again'. Why not do it properly first time? What is the rush in bringing up a classic computer? And for a test, use the TTL pulse generator you have on your bench. Or even an NE555 astable (yes, with a decent capacitor it is stable enough for a baud rate generator, I've used it). Heck, I've worked on machines that used a 2 transistor astable multivibrator for the baud clock. Surely you have 2N3904s in the spares box? Incidentally, if certain horologists heard you would use MDF in an antique clock, you would be going home with a pendulum rod shoved where the sun don't shine ;-) If you have the ttl logic bits lying around and know how to use them, fine. Still would probably need debugging. FWIW I have made programmable dividers on a couple of occasions recently (one was a 100/120 flash-per-second stroboscope, the other was the transmitter half of a modem to talk to TDDs). Both of them worked first time. I guess it's just what I am used to. Exactly. And for somebody who doesn't already have a full stock of TTL parts on hand, a different solution may 'Full stock of TTL parts' ??? You make it sound like I am suggesting using lookahead carry generators, parallel multipliers, Excess 3 to 1-of-n decoders and the like (all of which exist(ed) in TTL). No, I am suggesting using some very common counter and gate ICs. How are you going to fix a TTL-based machine like your 11/730 without spares and without knowing what the ICs do? present itself. I play with gear from WWII military radios up through thoroughly modern electronics. When I work on a WWII radio, it might be considered cheating to poke at it with my Fluke multimeter, Tek DSO, HP spectrum analyzer or HP synthesized signal generator (the latter two of which are slaved to my GPS-disciplined frequency standard), but those are the tools I have on hand, so those are the tools that I use. It is cheating :-) More seriously, tools are one thing. And had it been suggested that as a quick fix you took the TTL output from a sig-gen or took the output and clipped it to TTL with a transistor buffer then that would IMHO be reasonable (even if said sig-gen contained many times the number of components of the rest of the machine). But to make a custom solution that is over-complicated IMHO is the wrong way to do it. You might well inject your HP sig-gen into the mixer (first detector) stage of your WW2 radio to get it going if the local oscillator had failed, or if you didn't have the right crystal, or whatever. But I hope you wouldn't replace the valve (tube) based local oscillator in such a set with a digital synthesiser as a permanent 'repair' -tony
RE: using new technology on old machines. Was: PDP-12 Restoration at the RICM
I also think it is in the spirit of the computer - using what is available to fix a problem at hand. I think the arduino was overkill when an attiny (smaller, easier to hide) would probably serve just as well. Would you put plastic handles on a piecc of antique furniture? Would you make the seatboard for an antique longcase clock from MDF? Both are easily reversable, BTW. If you have the ttl logic bits lying around and know how to use them, fine. Still would probably need debugging. FWIW I have made programmable dividers on a couple of occasions recently (one was a 100/120 flash-per-second stroboscope, the other was the transmitter half of a modem to talk to TDDs). Both of them worked first time. I guess it's just what I am used to. -tony
RE: FPGA tricks - Re: using new technology on old machines. Was: PDP-12 Restoration at the RICM
-Original Message- From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of ben Sent: 15 June 2015 17:18 To: cctalk@classiccmp.org Subject: Re: FPGA tricks - Re: using new technology on old machines. Was: PDP-12 Restoration at the RICM On 6/15/2015 9:08 AM, Toby Thain wrote: On 2015-06-15 9:35 AM, Dave G4UGM wrote: I don't think it is over kill. If you want over kill try this:- https://www.youtube.com/watch?v=ALXax3Gydl8 and FPGA implementation of the Baby or SSEM which had 32x32 bits of RAM. The implementation uses around 1% of the Spartan 3E 1200K gates, and that includes the logic to generate the VGA which is around 50% of the circuit. I expect to get it on a 100K gate chip but that’s still over-kill. Speaking of VGA, you might like this: http://www.fpgarelated.com/showarticle/42.php --Toby But alas the software does *not* support the older chips. How old is old? I managed to get a copy of ISE10.1 downloaded, installed and running without phoning, ringing or otherwise jumping through hoops. That supports the Spartan 2 which has been obsolete for some time.. If you want to play with some Spartan 2 chips contact me off-line. You want to make a mod 5 years down the road, sorry we do not support that model any more. TTL needs to be stock piled now for the next +50 years. I finally got 18 bit FPGA computer (DE1) design I like, that is early 70's speed. 1.5 us core. What I am having problems is finding a good book on Operating Systems from that Era that is online, any one know a good book? I have software that I need to write. Ben.
Re: FPGA tricks - Re: using new technology on old machines. Was: PDP-12 Restoration at the RICM
On 6/15/2015 10:57 AM, Dave G4UGM wrote: But alas the software does *not* support the older chips. How old is old? I managed to get a copy of ISE10.1 downloaded, installed and running without phoning, ringing or otherwise jumping through hoops. That supports the Spartan 2 which has been obsolete for some time.. If you want to play with some Spartan 2 chips contact me off-line. I use the other brand. I also program it in ADHL, that I can understand. I also use crash and burn debugging with paper listings, Ben.
RE: using new technology on old machines. Was: PDP-12 Restoration at the RICM
We're talking about putting in a rather complex computer to generate a baud rate. Are people really that handicapped when it comes to building hardware nowadays? Speaking for myself, yes. Unfortunately I believe you. Use at least a thousand times more components than you need to. Now, if the alternative is reading up on crystals, oscillators, dividers and related support chips, figure out where to buy and then wait for the parts to ship, which option do you think I will choose? In general this worries me if you are restoring a vintage minicomputer. How on earth can you hope to fix a TTL-built CPU without knowing the common TTL chips and without having a few on-hand? -tony
Re: FPGA tricks - Re: using new technology on old machines. Was: PDP-12 Restoration at the RICM
On 6/15/2015 11:33 AM, Paul Koning wrote: On Jun 15, 2015, at 1:28 PM, ben bfranc...@jetnet.ab.ca wrote: On 6/15/2015 10:57 AM, Dave G4UGM wrote: But alas the software does *not* support the older chips. How old is old? I managed to get a copy of ISE10.1 downloaded, installed and running without phoning, ringing or otherwise jumping through hoops. That supports the Spartan 2 which has been obsolete for some time.. If you want to play with some Spartan 2 chips contact me off-line. I use the other brand. I also program it in ADHL, that I can understand. I also use crash and burn debugging with paper listings, Ben. What’s ADHL? I know VHDL and haven’t yet learned Verilog. I once used an old proprietary CPLD language with Lattice (Lattice-HDL???). Very primitive and not particularly easy to use, not to mention too limited for anything beyond little CPLDs. That was Altera's programing language. Since I have the hardware here I have no need to move to anything else. Mind you the hardware docs are sparse, a few datasheets on the major chips. VHDL and Verilog have the benefit of being standards, and at least for VHDL there are open source tools available (ghdl) that work well. As soon as you get real hardware, every brand is different. The nice thing about standards is that there are so many of them to choose from paul Ben.
Re: FPGA tricks - Re: using new technology on old machines. Was: PDP-12 Restoration at the RICM
On Jun 15, 2015, at 09:18, ben bfranc...@jetnet.ab.ca wrote: But alas the software does *not* support the older chips. You want to make a mod 5 years down the road, sorry we do not support that model any more. TTL needs to be stock piled now for the next +50 years. Good point. Just as TTL needs to be stockpiled, I think we should be in a habit of archiving virtual machines containing development software installed in a compatible operating system, so the software can still hopefully be used long after the original machines are obsolete. Much like we often use SIMH now for maintenance tasks to help bring up old machines that no longer live in an ecosystem of similar machines. -- Mark J. Blair, NF6X n...@nf6x.net http://www.nf6x.net/
Re: using new technology on old machines. Was: PDP-12 Restoration at the RICM
On Jun 15, 2015, at 11:54 , tony duell a...@p850ug1.demon.co.uk wrote: Why not do it properly first time? What is the rush in bringing up a classic computer? And for a test, use the TTL pulse generator you have on your bench. I don't have one. I have a lot of test equipment, but mostly for RF work. If I needed to generate TTL pulses, I'd probably pull out a microcontroller development board of some sort, because that's what I have sitting around. Or even an NE555 astable (yes, with a decent capacitor it is stable enough for a baud rate generator, I've used it). Heck, I've worked on machines that used a 2 transistor astable multivibrator for the baud clock. Surely you have 2N3904s in the spares box? No, I have neither 2N3904s nor NE555s in my spares. I could replace an M1 Carbine trigger spring on the spot, or a HMMWV taillamp housing, or most of the tubes in a 1950s US military vehicular radio, or an AR15 recoil buffer, or an Enfield Mk. 2 firing pin, or countless other things. I could test a diesel engine injector for pop-off pressure and slobber, or pull diagnostic codes from an M923's antilock air brake system, or check a transmitter for spurs up to 2.9 GHz, or measure a TTL clock frequency to within 50 parts per trillion absolute accuracy. But I don't have a TTL signal generator. Not everybody has the same junkbox, background, interests, equipment or capabilities, so not everybody will do things the same way that you do. Should I criticize you for not having SAE grade 8 hardware on hand, or Bristo wrenches for working on a Collins PTO, or spare Packard connectors for a post-Korean vintage US military vehicle, or the right kind of grease for an M1 Garand bolt, or the special screwdriver for the tiny little center-drilled screws in a telephone patch plug, or an M1 carbine gas piston plug wrench, all of which I have on hand? (No, I shouldn't, and I wouldn't.) Incidentally, if certain horologists heard you would use MDF in an antique clock, you would be going home with a pendulum rod shoved where the sun don't shine ;-) Well, maybe I'd educate them that Underwood and Remington Rand didn't just make typewriters before they got that pendulum rod in very far. ;) -- Mark J. Blair, NF6X n...@nf6x.net http://www.nf6x.net/
Re: using new technology on old machines. Was: PDP-12 Restoration at the RICM
On Jun 15, 2015, at 12:15 , tony duell a...@p850ug1.demon.co.uk wrote: I am very worried that people would rather use a microcontroller than change a couple of passives. Can't anyone read a schematic and think The exact same argument could be made for somebody using an NE555 instead of discrete transistors to blink an LED, or discrete transistors instead of vacuum tubes to blink a neon glow lamp. For that matter, I might call somebody a slacker for blinking an LED with an NE555 instead of an LM3909. But LM3909s are no longer manufacturer or stocked. An NE555 only costs $.50 vs. about $1 for an ATtiny, but these days, folks under the age of 40 are a lot more likely to have an ATtiny (or more likely, an ATmega on an Arduino board) sitting on their desktop. -- Mark J. Blair, NF6X n...@nf6x.net http://www.nf6x.net/
Re: using new technology on old machines. Was: PDP-12 Restoration at the RICM
On Mon, Jun 15, 2015 at 04:55:57PM +, tony duell wrote: Unfortunately I believe you. Use at least a thousand times more components than you need to. Actually it's just two, a Teensy and a usb cable. (Sorry, I couldn't resist). In general this worries me if you are restoring a vintage minicomputer. How on earth can you hope to fix a TTL-built CPU without knowing the common TTL chips and without having a few on-hand? How do you suggest I learn? I believe you had a father that got you of to a good start and perhaps you even took a few classes. My father was great but knew very little about electronics. And TTL on the minicomputer level was way out of fashion when I went to school. Certainly no excuse, but one of the main reasons I'm in this hobby is to learn! And boy have I learned a lot since I got started. I'm not at your level yet.. but perhaps in a few years I'll be a tenth of the way there :) It might please you to hear that the Teensy I'm talking about is in a socket on a perfboard together with a handfull of 74165 and 74374 which I've wirewrapped in proper wirewrapping sockets. It will become a USB interface for my 11/70 front panel. The Teensy was the simplest/cheapest way to get a usb interface with lots of I/O pins. (Why usb? to get a connection to simh on one of those newfangled Pi-things) Cheers, Pontus.
RE: using new technology on old machines. Was: PDP-12 Restoration at the RICM
We're talking about putting in a rather complex computer to generate a baud rate. Are people really that handicapped when it comes to building hardware nowadays? Are people aware how easy baud generators are? I've jsut turned up the M452 schematic. Has anyone else looked at it? It's a expletive RC transistorised oscillator driving a /4 divider chain. Are you seriously telling me you don't have a junk box full of random R's and C's and you can't change the timing components to get whatever rate you want out of it? I am very worried that people would rather use a microcontroller than change a couple of passives. Can't anyone read a schematic and think -tony
Re: O/S design implementation - was Re: FPGA tricks - Re: using new technology on old machines
On Jun 15, 2015, at 8:09 PM, ben bfranc...@jetnet.ab.ca wrote: On 6/15/2015 4:42 PM, Toby Thain wrote: I think Tanenbaum should be fine? A lot of it is fairly timeless. The latest version is *useless*. The racoons on the cover tells alot. Or you could just read “The structure of the THE operating system” by E.W.Dijkstra, and follow its principles. paul
Re: O/S design implementation - was Re: FPGA tricks - Re: using new technology on old machines
On 2015-06-15 9:21 PM, ben wrote: On 6/15/2015 7:11 PM, Paul Koning wrote: On Jun 15, 2015, at 8:09 PM, ben bfranc...@jetnet.ab.ca wrote: On 6/15/2015 4:42 PM, Toby Thain wrote: I think Tanenbaum should be fine? A lot of it is fairly timeless. The latest version is *useless*. The racoons on the cover tells alot. Or you could just read “The structure of the THE operating system” by E.W.Dijkstra, and follow its principles. (The Structure of the THE-Multiprogramming System) a) Not online to my knowledge Are you sure? http://ur1.ca/mu60x b) Most likely in German What Mouse said, but it's actually in English. --Toby c) and the most important thing ... I do not have any Mag Tape paul Ben.
Re: using new technology on old machines
On Jun 15, 2015, at 2:19 PM, Noel Chiappa j...@mercury.lcs.mit.edu wrote: Having said that, _I_ don't have 2N3904s nor NE555s around either! I do have a modest number of parts (e.g. 4164's, 40-ping Berg shells, .250 tab hardware, etc, etc) - a large enough collection that I just had to re-organize and add more parts holders (although that was mostly because I went berserk at the local Radio Shack in the 80% off sale). But it takes a long time to build up a really comprehensive collection of parts. I got into the arcade pinball hobby over a decade ago, would travel to people home’s and fix their machines, and really got into the retro computing thing about 3 years ago. I don’t have a huge collection of parts either, just what I bought to fix something or make something. One nice thing is there is a lot of crossover of technology with both hobbies, so I’m often surprised to find I happen to already have something on hand. What sucks is ordering things that I actually *did* have because I didn’t know. I’ve slowly started to be a little more organized but things are still scattered all over in different boxes. I decided to standardize on those 24 compartment and 18 compartment storage containers from Harbor Freight since they fit quite well in the wooden crates I’ve been making. http://imgur.com/a/UsFn3 -- Follow me on twitter: @FozzTexx Check out my blog: http://insentricity.com
Re: using new technology on old machines
On Jun 15, 2015, at 15:07 , Noel Chiappa j...@mercury.lcs.mit.edu wrote: One wonders why some manufacturer didn't realize there was money to be made in smaller cards (now less competition, but still enough demand to drive the prices up) and keep making them. Because the chip fab equipment that was used to make the dies in the spaller parts has probably already been retired in favor for equipment suitable for smaller process geometries, and there's no point in making dies with storage capacity smaller than what fits in the minimum die size dictated by the pad ring necessary for the I/O. There actually is a lower limit to memory capacity, beyond which the cost cannot be reduced and the die cannot be shrunk. We call such chips pad limited, as in the I/O pads dictate a minimum die size, and the die will cost almost exactly the same (save for minor yield variations) whether the middle is filled with gates or not. I don't think that the hangups of a very few people justify ignoring the economics of semiconductor manufacturing. -- Mark J. Blair, NF6X n...@nf6x.net http://www.nf6x.net/
Re: using new technology on old machines. Was: PDP-12 Restoration at the RICM
On Mon, Jun 15, 2015 at 04:53:01PM +, tony duell wrote: I also think it is in the spirit of the computer - using what is available to fix a problem at hand. I think the arduino was overkill when an attiny (smaller, easier to hide) would probably serve just as well. Would you put plastic handles on a piecc of antique furniture? Would you make the seatboard for an antique longcase clock from MDF? Both are easily reversable, BTW. No but I would put an electric heater in a steam engine if it meant restoration would progress faster. (yes, feel free to lecture me how big that heater would have to be...) /P
Re: using new technology on old machines. Was: PDP-12 Restoration at the RICM
On Mon, Jun 15, 2015 at 01:59:11PM -0700, Mark J. Blair wrote: Big. VERY big. :) And one more thing (until the next thing comes to mind): I consider this to be an enjoyable and level-headed debate, just in case anybody gets the mistaken impression that I'm trying to come down hard on Tony at all. So far I feel we've been civil :) I too hope I'm not coming of to harsch.. I feel a bit cranky because its 25 degrees celsius in my workshop :/ Speaking of steam engines and boilers. I saw a 1918 Bucyrus steam shovel this weekend. Mostly rust, but under slooow restoration. /P
Re: using new technology on old machines
From: Mark J. Blair I could replace an M1 Carbine trigger spring on the spot, or a HMMWV taillamp housing ... Should I criticize you for not having SAE grade 8 hardware on hand, or Bristo wrenches I think Tony's point was that someone who's into vintage computers ought to have a stock of suitable parts for them. So unless he's into older guns, or cars, were he not to have things like SAE 8 hardware around, that would be understandable - he doesn't do them. Having said that, _I_ don't have 2N3904s nor NE555s around either! I do have a modest number of parts (e.g. 4164's, 40-ping Berg shells, .250 tab hardware, etc, etc) - a large enough collection that I just had to re-organize and add more parts holders (although that was mostly because I went berserk at the local Radio Shack in the 80% off sale). But it takes a long time to build up a really comprehensive collection of parts. It's funny, I was thinking of this exact topic last night - wondering if I could find someone who's selling off a large cabinet full of mixed spares! (I was thinking of the experience of one list member, who lucked into such.) I could certainly use it! Noel
Re: using new technology on old machines. Was: PDP-12 Restoration at the RICM
On Jun 15, 2015, at 14:56 , Dave G4UGM dave.g4...@gmail.com wrote: A friend of mine refused to buy modern SD Cards because there was no way he was going to fill them. Trouble is that although smaller SD cards were available they were way more expensive (being discontinued and therefore rare and valuable).. He struggled with buying a larger card only to waste most of it, or buy a smaller one and waste his money I had that same mental hangup when thinking about how I might design an SD card based TU58 emulator in the same form factor as a TU58 cartridge (still on my to-do list, by the way). How was I going to implement the user interface? It's not like there's much room for an LCD or buttons on the edge of a TU58 cartridge. Then it finally hit me: SD cards are cheaper than TU58 cartridges ever were. So why not just use the first 256k, ignore the rest of the card, and swap cards exactly the way one would swap TU58 cartridges, with one image on each card? Yeah, 99% of the card is wasted, but they're presently cheap and plentiful enough to ignore that. Ok, I might actually have the emulator read a file from a DOS filesystem rather than using the first 256k of raw blocks. But it'll probably just be a fixed filename with no controls to select a different one, and the expectation that an entire (cheap, plentiful) SD card will be devoted to each tape image. At least this way, other things can also be on the card, so it doesn't need to be wasted if not needed. Your friend should understand that the larger card that he would be wasting probably has less silicon in it than the older one with less capacity. The cheapest card that is reliable, fast enough and large enough for his task is the best one to get, even if it's much larger than he needs. Just one of the weird parts of the Moore's Law curve! Hmm, this reminds me that back in the day, floppy disks were expensive. We have it easy with cheap and plentiful SD cards nowadays. But maybe my perspective is different as an employed adult rather than a teenager with limited funds? Anyway, SD cards seem to be cheap enough to be nearly disposable nowadays. -- Mark J. Blair, NF6X n...@nf6x.net http://www.nf6x.net/
RE: using new technology on old machines. Was: PDP-12 Restoration at the RICM
A friend of mine refused to buy modern SD Cards because there was no way he was going to fill them. Trouble is that although smaller SD cards were available they were way more expensive (being discontinued and therefore rare and valuable).. He struggled with buying a larger card only to waste most of it, or buy a smaller one and waste his money Dave Wade G4UGM -Original Message- From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Mark J. Blair Sent: 15 June 2015 21:56 To: General Discussion: On-Topic and Off-Topic Posts Subject: Re: using new technology on old machines. Was: PDP-12 Restoration at the RICM On Jun 15, 2015, at 13:46 , Pontus Pihlgren pon...@update.uu.se wrote: On Mon, Jun 15, 2015 at 04:55:57PM +, tony duell wrote: Unfortunately I believe you. Use at least a thousand times more components than you need to. Actually it's just two, a Teensy and a usb cable. (Sorry, I couldn't resist). LOL! I must admit that I used to scorn those durned kids using Arduinos to do the job of a 555. But then I pulled my head out of my ass and realized that times change, nowadays a microcontroller is as cheap and common component as a 555 was when I was a snotty kid, and the new-fangled maker movement with its Arduinos and serial-controlled addressable LEDs and conductive thread is keeping younger people designing things and making them instead of just being dumb consumers. It's all good stuff! And once I got a better idea of how much it costs to keep an engineer breathing for an hour, I also realized that it often makes more sense to overkill the heck out of a task with a $20 micro board than it would to spend even a half hour longer doing it the right way. -- Mark J. Blair, NF6X n...@nf6x.net http://www.nf6x.net/
Re: using new technology on old machines
From: Dave G4UGM Trouble is that although smaller SD cards were available they were way more expensive (being discontinued and therefore rare and valuable).. One wonders why some manufacturer didn't realize there was money to be made in smaller cards (now less competition, but still enough demand to drive the prices up) and keep making them. Noel
Re: using new technology on old machines
On Jun 15, 2015, at 14:19 , Noel Chiappa j...@mercury.lcs.mit.edu wrote: I think Tony's point was that someone who's into vintage computers ought to have a stock of suitable parts for them. Yes, that'll likely be true once they have been in the hobby for a while. But for somebody who has gotten into it recently, and otherwise hasn't had reason to touch a DIP packaged part since the early 1990s (even while being a full-time electrical engineer and full-time electronics/etc. hobbyist), it can't be taken for granted that they have a parts drawer full of misc. 74LS parts. I have a vast junkbox, and I regularly order electronic components both professionally and for my hobby... and I still don't have a lot of TTL parts on hand. -- Mark J. Blair, NF6X n...@nf6x.net http://www.nf6x.net/
Re: using new technology on old machines. Was: PDP-12 Restoration at the RICM
On Jun 15, 2015, at 14:27 , Robert Jarratt robert.jarr...@ntlworld.com wrote: This particular thread has all the hallmarks of one that *could* descend into a flame war. Thank you for avoiding that! I think we're doing ok. The same folks having a spirited debate in this thread are carrying on just fine together in other threads at the same time, so I don't think the fangs are being exposed. :) -- Mark J. Blair, NF6X n...@nf6x.net http://www.nf6x.net/
O/S design implementation - was Re: FPGA tricks - Re: using new technology on old machines
On 2015-06-15 12:18 PM, ben wrote: On 6/15/2015 9:08 AM, Toby Thain wrote: On 2015-06-15 9:35 AM, Dave G4UGM wrote: I don't think it is over kill. If you want over kill try this:- https://www.youtube.com/watch?v=ALXax3Gydl8 and FPGA implementation of the Baby or SSEM which had 32x32 bits of RAM. The implementation uses around 1% of the Spartan 3E 1200K gates, and that includes the logic to generate the VGA which is around 50% of the circuit. I expect to get it on a 100K gate chip but that’s still over-kill. Speaking of VGA, you might like this: http://www.fpgarelated.com/showarticle/42.php --Toby But alas the software does *not* support the older chips. You want to make a mod 5 years down the road, sorry we do not support that model any more. TTL needs to be stock piled now for the next +50 years. I finally got 18 bit FPGA computer (DE1) design I like, that is early 70's speed. 1.5 us core. What I am having problems is finding a good book on Operating Systems from that Era that is online, any one know a good book? I have software that I need to write. I think Tanenbaum should be fine? A lot of it is fairly timeless. https://archive.org/details/OperatingSystemsDesignImplementation --Toby Ben.
Obsolescence proprietary FPGA toolchains - Re: FPGA tricks - Re: using new technology on old machines
On 2015-06-15 12:57 PM, Dave G4UGM wrote: -Original Message- From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of ben Sent: 15 June 2015 17:18 To: cctalk@classiccmp.org Subject: Re: FPGA tricks - Re: using new technology on old machines. Was: PDP-12 Restoration at the RICM On 6/15/2015 9:08 AM, Toby Thain wrote: On 2015-06-15 9:35 AM, Dave G4UGM wrote: I don't think it is over kill. If you want over kill try this:- https://www.youtube.com/watch?v=ALXax3Gydl8 and FPGA implementation of the Baby or SSEM which had 32x32 bits of RAM. The implementation uses around 1% of the Spartan 3E 1200K gates, and that includes the logic to generate the VGA which is around 50% of the circuit. I expect to get it on a 100K gate chip but that’s still over-kill. Speaking of VGA, you might like this: http://www.fpgarelated.com/showarticle/42.php --Toby But alas the software does *not* support the older chips. How old is old? I managed to get a copy of ISE10.1 downloaded, installed and running without phoning, ringing or otherwise jumping through hoops. That supports the Spartan 2 which has been obsolete for some time.. If you want to play with some Spartan 2 chips contact me off-line. Altera has the old version of Quartus for download on their site. I had to take advantage of this to get a version that would compile for my Cyclone I. :) Anyone with older chips might want to grab the appropriate versions while they are still there... --Toby You want to make a mod 5 years down the road, sorry we do not support that model any more. TTL needs to be stock piled now for the next +50 years. I finally got 18 bit FPGA computer (DE1) design I like, that is early 70's speed. 1.5 us core. What I am having problems is finding a good book on Operating Systems from that Era that is online, any one know a good book? I have software that I need to write. Ben.
