[cctalk] Re: interlace [was: NTSC TV demodulator ]
> On 05/20/2024 12:06 PM CDT CAREY SCHUG via cctalk > wrote: > > > so, just curious. how do digital TVs (and monitors) work? I presume the dots > are a rectangle, not sloping down to the right, no half a line at the top and > bottom. Do they just assume the brain can't tell that (for the converted old > analog tv signal) the image therefor slopes UP very slightly to the right > from what it "should" be? and the top line is blank on the left side because > that is the interlace frame? > > --Carey > Well, the slope is VERY slight. Approximately 1/500 of the picture height.Probably impossible to detect with the eye. In the old days when us older folks were young, the TV camera image was generated the same way, with a scanned beam. So then the generated image matched the displayed image. But Around the end of the 70s when solid state image sensors started coming into use, the generated image didn't match that displayed on the CRT. But nobody noticed. Now, almost all pictures are generated by some type of solid state generator and the lines aren't angled, and neither are the displayed lines. So, again, it matches. The NTSC signal defines 525 lines per "frame," each frame made of two "fields" of 262 1/2 lines (I may have frame and field mixed up.) In one field, the half line is at the top. It is at the bottom on the other. But out of those 525 total lines, only around 480 (I forget exactly) are displayable. The non-displayed lines are split between the top and bottom. So the two half-lines aren't diplayable. Those non-displayed lines are used for all sorts of things, including closed captioning. Old analog TVs and monitors make any changes for different types of signals; they just (attempted to ) displayed whatever was thrown at them. Will
[cctalk] Re: interlace [was: NTSC TV demodulator ]
> On 05/20/2024 1:02 PM CDT Wayne S via cctalk wrote: > > > In the vt100, setup menu “B” had an interlace on or off setting. > I just looked it up. > > That is almost certainly setting what type of signal is generated. Like a TV of the same era, the monitor (display) portion doesn't care; it just displays what it is sent. That is very different from a monitor setting that sets either interlaced or non-interlaced. Some reasons why you might prefer one over the other on the same screen: non-interlaced would have a horizontal gap between displayed lines whereas interlaced would fill them in. However, interlaced is more prone to flickering, which can be very tiring to the eyes and cause headaches. Will
[cctalk] Re: NTSC TV demodulator
> On 05/19/2024 8:50 AM CDT Henry Bent via cctalk wrote: > > > On Sun, May 19, 2024, 08:08 Will Cooke via cctalk > wrote: > > > I have a couple of 70s/80s "home" computers (e.g. Radio Shack Color > > Computer) that are intended to connect to a TV set. They don't have easily > > available composite video, even internally, only modulated RF output. > > Currently I have an old CRT TV that I use with them, but for various > > reasons that isn't practical long-term. > > Does anyone know of a small TV tuner that tunes old analog TV channels (US > > NTSC) and outputs composite or VGA or HDMI signals? I've looked around a > > bit but haven't found anything. It's relatively easy to build one, but I > > would prefer a pre-built solution. And I'm sure others have run into this > > same problem. > > I just googled "rf to HDMI" and there appear to be several options from the > usual large sellers. As I have no experience with them, I don't want to > endorse any particular model. My assumption is that they would take output > on NTSC channel 3 or 4, as was common for equipment of the time. > > -Henry > > > Perfect! Thanks. I Googled all sorts of things except "rf". Will
[cctalk] NTSC TV demodulator
I have a couple of 70s/80s "home" computers (e.g. Radio Shack Color Computer) that are intended to connect to a TV set. They don't have easily available composite video, even internally, only modulated RF output. Currently I have an old CRT TV that I use with them, but for various reasons that isn't practical long-term. Does anyone know of a small TV tuner that tunes old analog TV channels (US NTSC) and outputs composite or VGA or HDMI signals? I've looked around a bit but haven't found anything. It's relatively easy to build one, but I would prefer a pre-built solution. And I'm sure others have run into this same problem. Thanks, Will
[cctalk] Re: DOS p-System Pascal: (Was: Saga of CP/M)
> On 05/09/2024 5:46 PM CDT ben via cctalk wrote: > > Did any one make a REAL TIME OS the 386? There were / are quite a few. https://en.wikipedia.org/wiki/Comparison_of_real-time_operating_systems The 386ex was specifically intended for embedded systems. The first one that came to mind, and caused me to find that list, was RTEMS that I think was originally written on/for the 386. https://en.wikipedia.org/wiki/RTEMS Will Grownups never understand anything by themselves and it is tiresome for children to be always and forever explaining things to them, Antoine de Saint-Exupery in The Little Prince
[cctalk] Re: DOS p-System Pascal: (Was: Saga of CP/M)
> On 05/09/2024 7:24 AM CDT Bill Degnan via cctalk > wrote: > > > Mike > I was thinking operating systems and the early launch version IBM PC, but > yes once the hardware caught up Turbo Pascal was a popular program now that > I think about it. So I guess the PC versions just needed more horsepower > and some useful libraries. But Pascal never matched C > Bill > My perception is that UCSD P system was quite popular in the late 70s on Apple and other systems. Then when the university turned it over to commercial marketing (SofTech?), the silly games played turned a lot of people off. Like trying to revoke previously granted licenses and charging "too much." I suspect that left a bad taste in a lot of mouths that might otherwise have been interested. But I was a distant observer at the time; I couldn't afford more than my ZX-81 and VIC-20. Will Grownups never understand anything by themselves and it is tiresome for children to be always and forever explaining things to them, Antoine de Saint-Exupery in The Little Prince
[cctalk] Re: Double Density 3.5" Floppy Disks
> On 05/06/2024 8:58 PM CDT Fred Cisin via cctalk wrote: > > > Ignorant question: > > Q: When looking for current availability of bulk tape/disk demagnetizers, > on eBay, I ran into a lot of CD/DVD demagnetizers > What kind of a problem do they have with magnetism? > > Or is this like the DVD REWINDERS? A must-have accessory to go with your oxygen-free cables. https://www.tnt-audio.com/accessories/vs_demagnetizer_e.html Will Grownups never understand anything by themselves and it is tiresome for children to be always and forever explaining things to them, Antoine de Saint-Exupery in The Little Prince
[cctalk] MS-DOS source code
Some may find this interesting. Microsoft has released the source for MS-DOS versions 1.25, 2, and 4. https://github.com/microsoft/MS-DOS Will Grownups never understand anything by themselves and it is tiresome for children to be always and forever explaining things to them, Antoine de Saint-Exupery in The Little Prince
[cctalk] Re: Z80 vs other microprocessors of the time.
> On 04/21/2024 7:06 PM CDT Peter Coghlan via cctalk > wrote: > > > > Why is that? Did the Z80 take more cycles to implement it's more complex > instructions? Is this an early example of RISC vs CISC? > > Regards, > Peter Coghlan I'm certainly no authority, but I have programmed both processors in assembly and studied them somewhat. It took many years for me to believe that the 6502 was "faster" than the Z80, but now I'm (mostly) a believer. So here is my take. First, yes, the Z80 takes roughly 4 times as many clock cycles per instruction. Where the 6502 can complete a simple instruction in a single clock, the Z80 takes a minimum of four. The 02 certainly has a simpler architecture, but calling it a RISC machine would probably make the RISC believers cringe. It is simple, but it doesn't follow the pattern of lots of registers (well, maybe) and a load/store architecture. But that may be its strongest point. The zero page instructions effectively make the first 256 bytes of RAM into a large (128 or 256) register file. Along with all those pseudo-registers in page zero, the 02 has some really nice addressing modes. In effect, all those pseudo registers can be used as index registers in addition to directly holding operands. The simple, fast instructions operating on 8 bit registers runs fast. In the Z80, there are a fair number of registers, but most are limited to what they can be used for. You almost always have to go through the accumulator (register A.) So you end up moving stuff between memory and various registers, often shuffling stuff around once loaded, then store it back to memory. The Z80 has the IX and IY index registers, but they are even slower, adding another machine cycle (4 clocks?) to an already slowish instruction just for the fetch, then another memory cycle. If you have to load the operand then store the result, that doubles the extra time needed. So all of that leads to faster assembly language on the 02. Good 6502 programmers (I'm NOT one of them) know tons of tricks to get the most out of it, too. People spent years learning the ins and outs of that particular processor. I think the Z80 didn't get that kind of love, at least not as much. Most Z80 machines were running CP/M and most didn't have the graphics and sound that made the 02 machines no nice for home computers and games. In addition, an awful lot of Z80 code/programmers were part time, moving to and from the 8080 which was really a different machine. As a rough approximation I would say that a Z80 would require somewhere between 4 to 8 times the clock for equivalent assembly language performance. No doubt others will have other opinions. However, the Z80 was probably more likable by the computer science people. And it was a LOT easier to write a halfway decent compiler for. It didn't need as many "tricks" to make it perform. If you look at compiled code for the two, you will usually either find severe limitations on the 02 or very slow code. Especially if you are looking at any "modern" language (Algol family, such as C or Pascal.) A BASIC (or perhaps even Fortran) compiler that doesn't have all the local variables and nested structure will usually fare better. Anyway, that's my 1/2 cent worth. Take it for what its worth. Will Grownups never understand anything by themselves and it is tiresome for children to be always and forever explaining things to them, Antoine de Saint-Exupery in The Little Prince
[cctalk] Re: Bomar 901b My wife found in my stuff. Is this as scarce at it seems?s,?
I think he means Bowmar https://spectrum.ieee.org/the-consumer-electronics-hall-of-fame-bowmar-901b > On 04/16/2024 5:34 AM CDT ED SHARPE via cctalk wrote: > > > No bomar brand > > Sent from AOL on Android > > On Mon, Apr 15, 2024 at 7:15 PM, Wayne S wrote: > Bomar as in the Bomber Aircraft? > > Sent from my iPhone > > > On Apr 15, 2024, at 19:04, ED SHARPE via cctalk > > wrote: > > > > Bomar 901b My wife found in my stuff. Is this as scarce at it seems?s,? > > > > > > Sent from AOL on Android Grownups never understand anything by themselves and it is tiresome for children to be always and forever explaining things to them, Antoine de Saint-Exupery in The Little Prince
[cctalk] Re: Turbo Pascal Kermit for CP/M
You mentioned that the TRS-80(s) have hard disks. Perhaps the extra space taken by the hard disk bios is the culprit. Maybe a floppy-only machine (with floppy only bios) is the only way to compile it. Will Grownups never understand anything by themselves and it is tiresome for children to be always and forever explaining things to them, Antoine de Saint-Exupery in The Little Prince
[cctalk] Re: oscilloscopes
I used to have a Tek 453(?) that was really nice. I sold it when I got a Tek 7201(?) 1Ghz model. I recently sold it. I hated getting rid of it but it was big enough to be used as a small desk and weighed more than my back could handle any more. I still have a 561A that I've been meaning to repair for 40 years. Any nuke preppers want it? It needs a new home. Bring a truck. Will Grownups never understand anything by themselves and it is tiresome for children to be always and forever explaining things to them, Antoine de Saint-Exupery in The Little Prince
[cctalk] Re: typical IC kits on Amazon and elsewhere
> On 03/30/2024 3:37 PM CDT Just Kant via cctalk wrote: > > > Clearly all or virtually all chineseum, correct? > > That being the case, um, what type.of.quality can be expected? Some are > fairly cheap. I guess thenworld isn't to be expected. I'm not clear on whether you mean some specific chips or in general, but here is my experience. For things that are in current production or recently discontinued, I have had extremely good luck with Chinese suppliers either from Amazon or Ebay. For things that are long out of production, such as 1802 (normal, not SOS) and 6502 processors, I've heard way too many horror stories so I look to ebay for new old stock or used from US or sometimes European suppliers. Again, I've had very good luck. In fact, I can't remember every getting any bad ones. YMMV Will Grownups never understand anything by themselves and it is tiresome for children to be always and forever explaining things to them, Antoine de Saint-Exupery in The Little Prince
[cctalk] Re: Paper tape in casettes...
> On 02/27/2024 2:13 PM CST Doug McIntyre via cctalk > wrote: > > > On Tue, Feb 27, 2024 at 11:10:34AM -0700, ben via cctalk wrote: > > PS: With low cost Chinese PCB's and vintage parts, why are people not > > building real hardware replica's of interesting machines. > But they are.. You might also want to have a look here: http://www.s100computers.com/My%20System%20Index%20Page.htm How about reproductions of "classic" S100 systems? Or a Z180? Or PDP-11 on S100? or 486? Will Grownups never understand anything by themselves and it is tiresome for children to be always and forever explaining things to them, Antoine de Saint-Exupery in The Little Prince
[cctalk] Re: VCF SoCal
> On 02/21/2024 5:01 AM CST Tony Duell via cctalk wrote: > > > > Did someone port it to other arch than ARM ? > The oldest version I know of ran on PDP11s. I am pretty sure there was > a 68000 version at one point too. > > -tony Wasn't the Amiga OS built on Tripos? Will Grownups never understand anything by themselves and it is tiresome for children to be always and forever explaining things to them, Antoine de Saint-Exupery in The Little Prince
[cctalk] Re: VCF SoCal
> On 01/31/2024 11:34 AM CST Henry Bent via cctalk > wrote: > > > On Wed, 31 Jan 2024 at 12:13, Liam Proven via cctalk > wrote: > > I write for an international audience and sometimes people from the > > USA are openly and repeatedly incredulous that "obscure" British > > computers -- that means they've never heard of them -- can be > > considered significant or important, even compared to American > > machines that were on sale in East Futtbuck Idaho for 6 weeks in > > Spring 1973 and have never been mentioned since. > > I wish that I were in a position to visit that VCF and see those machines. I as well. I do hope you will record it and make it available online somewhere. I have found that computers are much like motorcycles: many of the most interesting were never available in the US. Thanks, Will Grownups never understand anything by themselves and it is tiresome for children to be always and forever explaining things to them, Antoine de Saint-Exupery in The Little Prince
[cctalk] Re: FW: Re: ADM3a screen rot.
> On 01/29/2024 2:00 PM CST Sellam Abraham via cctalk > wrote: > > > On Mon, Jan 29, 2024 at 9:55 AM William Sudbrink via cctalk < > cctalk@classiccmp.org> wrote: > > dripping. Anyway, like Wile E Coyote, after I had shoved a screwdriver > > under the uncooperative anode cap and finally gotten it off, I suddenly > > thought "What the HE** did I just do???". > > Bill S. > > I think you were fine. That's how you discharge them anyway. You were > just missing the grounding wire :) > > Sellam > Perhaps we should edit that? You were just the grounding wire :) Will Grownups never understand anything by themselves and it is tiresome for children to be always and forever explaining things to them, Antoine de Saint-Exupery in The Little Prince
[cctalk] Re: WWVB
> On 01/14/2024 1:54 PM CST Jonathan Chapman via cctalk > wrote: > > > Bill, > > If it's an older clock it's probably tripping over a timecode transmission > format/modulation change. I forget the exact details but changes were > required to my old 8085-based Spectracom receiver. > > Thanks, > Jonathan > > On Sunday, January 14th, 2024 at 14:49, Bill Gunshannon via cctalk > wrote: > > > > > > > > This is kind computer related but maybe more ham radio related > > but I figure if anywhere, here is the place to find an answer. > > > > I have a SkyScan ATOMIC CLOCK. > > It is supposed to get its time from WWVB. > > The antenna icon that is supposed to mean it is receiving > > WWVB is on. > > > > Your probably wondering why I keep saying "supposed to". > > The clock is always wrong. Slow by about 2 minutes. > > > > Is there a known problem with WWVB? > > > > bill The details are on the NIST website. The format change was 2011 / 2012 ish. I think the details are in this paper. https://www.nist.gov/publications/new-improved-system-wwvb-broadcast I'm looking at my "atomic" clock and it agrees with the computer. Will Grownups never understand anything by themselves and it is tiresome for children to be always and forever explaining things to them, Antoine de Saint-Exupery in The Little Prince
[cctalk] Re: Intel 4004
More information is here: https://firstmicroprocessor.com/?doing_wp_cron=1700608229.8666059970855712890625 I think that is the designers (Rod Holt?) website. Apparently he won a legal battle to use the term "first microprocessor" for whatever that is worth. Will > On 11/21/2023 2:56 PM CST Brent Hilpert via cctalk > wrote: > > > On 2023-Nov-21, at 1:03 AM, ED SHARPE via cctalk wrote: > > On Mon, Nov 20, 2023 at 7:01 PM ben via cctalk > > wrote: > > > On 2023-11-20 5:36 p.m., Murray McCullough via cctalk wrote: > > > > On Nov. 15, 1971 Intel commercially released the 4004 microprocessor > > > > which > > > > some consider to be the first. Nonetheless, even if not in agreement, it > > > > made possible the instrument which drives the classic-computing > > > > industry or > > > > at the very least our hobby! > > > > > > > > Happy computing. > > > > > > > > Murray > > > https://retrocomputingforum.com/t/swiss-physicist-builds-complete-intel-4004-computer-out-of-smd-transistors/3738 > > > THE DIY VERSION > > So what are the other contenders and what do they bring to table > > A claim is made for the first microproc being the CADC processor of an early > flight-control system for the F-14, made by Garrett AiResearch ~ 1969. I > haven't looked into it in depth - or I don't know of detailed info being > available - but apparently it was a CPU made up of several LSI chips. In my > opinion that disqualifies it, but it's all into the mug's game of specifying > 'first at what?' If you want to build a ship, don't drum up people to collect wood and don't assign them tasks and work, but rather teach them to long for the endless immensity of the sea. Antoine de Saint-Exupery
[cctalk] Re: IBM 727 tape drive
> On 10/13/2023 8:56 AM CDT Paul Koning via cctalk > wrote: > > > > On Oct 13, 2023, at 4:41 AM, Christian Corti via cctalk > > wrote: > > > > ... > > And the interesting part will be to build the DC power supply for the many > > voltages (-270V, -130V, -60V, +140V, +270V) and the heater supply. > A good source for information on how to do that would be an older edition of > the ARRL Amateur Radio Handbook. Those can be found, from used book dealers. > I have a 1954 edition that would do well, though one from the 1960s is likely > also good (perhaps better since the earlier ones would have vacuum > rectifiers, which in a newly built supplly isn't optimal). > Several from the 80s and earlier are available on archive.org: https://archive.org/search?query=arrl+handbook%5B%5D=mediatype%3A%22texts%22 Will If you want to build a ship, don't drum up people to collect wood and don't assign them tasks and work, but rather teach them to long for the endless immensity of the sea. Antoine de Saint-Exupery
[cctalk] Re: Good C to FPGA/PLA compiler
> On 09/23/2023 3:25 PM CDT Warner Losh via cctalk > wrote: > > > On Sat, Sep 23, 2023, 12:31 PM Paul Koning via cctalk > wrote: > > > > > > > > On Sep 22, 2023, at 3:07 PM, Chuck Guzis via cctalk < > > cctalk@classiccmp.org> wrote: > > > > > > On 9/22/23 11:34, emanuel stiebler via cctalk wrote: > > >> There are still some 84pin chips out there(Altera & Xilinx). Sometimes > > >> they are pulls, or some 5V tolerant xilinx xc95l > > > > > > I still have a few 84 pin PLCC XC95108 5V CPLDs Originally, I did a > > > tape controller design with one before Xilinx discontinued them. I > > > figured that using a discontinued part was not the way forward, so I > > > dropped the project. Xilinx did/does have its ISE design suite, which > > > is fairly easy to use. > > > Eventually, it turned out that using a reasonably fast MCU with 5V > > > tolerant I/O worked just as well and avoided the "mystery in a chip" of > > > a CPLD. > > I used an Arduino Feather that way, for my PS-2 to LK201 converter. And > > while not 5V tolerant, a Raspberry Pico is a particularly powerful and > > cheap option; one of my projects could run DDCMP at 10 Mb/s including the > > "integral modem" compatible signaling. > > As I mentioned, 5V tolerant inputs can, at least for not too high speeds, > > be done simply by resistive voltage dividers. > > What's too fast in absolute terms? > > Warner > > paul > > > > > > I can't answer for Paul, but I can tell you how to do approximate calculations for yourself. You need to know two things: the equivalent parallel resistance (Thevenin equivalent) of the two series resistors and the input capacitance of the driven pin (including stray capacitance.) If you assume the input+stray capacitance is 10 pF (a reasonable first approximation) and the resistance is 1000 Ohms, the time constant (time for the signal to go from 0 to 63% of max) will be 1000 * 10E(-12) seconds or 10,000 picoseconds = 10 nanoseconds. That assumes the 5V output can switch instantaneously into the 5 mA or so load. I would double that for the real world. So the signal gets delayed around 20 nS and the output has to drive 5 mA or so. A more realistic divider might be 5K or 10K resistance for less power consumption and less strain on the output. With 10K you are looking at a delay of 100 to 200 nS. If the timing isn't critical you "might" be able to go as high as 5 MHz that way. But probably more like 1 MHz is more realistic. I've used voltage divider level translation at about 1 MHz, using something like 2200 and 4700 ohms for the divider (Thevenin equivalent 1500.) ymmv Will If you want to build a ship, don't drum up people to collect wood and don't assign them tasks and work, but rather teach them to long for the endless immensity of the sea. Antoine de Saint-Exupery
[cctalk] Re: Good C to FPGA/PLA compiler
> On 09/22/2023 6:26 PM CDT Mike Katz via cctalk wrote: > > > I plan on controlling the gate array with an RP2040 dual core cortex M0 > running at 133 MHz and 8 PIO processors. > Hi Mike, Since you are planning to use a micro anyway, and it doesn't appear you will need a great deal of external logic, you might consider one of the micros that has some programmable logic on board. Cypress PSOC is the prototypical example: https://www.infineon.com/cms/en/product/microcontroller/32-bit-psoc-arm-cortex-microcontroller/ They have a wide variety starting with Cortex M0 and going up, with varying amounts of programmable logic. Their tools are pretty nice, too, with pre-built modules and also allowing you to drop into raw HDL if you need or want to. They have a nice selection of reasonably priced dev boards to get started. Will If you want to build a ship, don't drum up people to collect wood and don't assign them tasks and work, but rather teach them to long for the endless immensity of the sea. Antoine de Saint-Exupery
[cctalk] Re: For Fred, especially: "Everything I know about floppy disks"
> On 09/11/2023 12:18 PM CDT ben via cctalk wrote: > > Did Algol in general have memory leaks?,or is just C and Windows. Not sure about the language, but at this point most of its programmers have memory leaks. Will If you want to build a ship, don't drum up people to collect wood and don't assign them tasks and work, but rather teach them to long for the endless immensity of the sea. Antoine de Saint-Exupery
[cctalk] Re: For Fred, especially: "Everything I know about floppy disks"
> On 09/10/2023 3:00 PM CDT Fred Cisin via cctalk wrote: > > > On Sun, 10 Sep 2023, Chuck Guzis via cctalk wrote: > > Now, let's talk about 2.8" and 3.25" drives; UK readers are certainly > > familiar with 3.0 inch CF drives used on Amstrads. > Amdek? sold a dual 3" drive in USA, marketed as external drives. > There were ads for it in one or more of the Coco magazines. > > And there were ads for it as external drives for Apple2! > Q: were those different electronics? OR did they include an FDC for > Apple2? > > > 3.25: > The three leading contenders for "Shirt pocket disks" were 3", 3.25", and > 3.5". There were many others, such as a 3.9" that IBM was rumored to be > planning. > But, for shirt pocket puspose, 3" seems the most promising. > There was extensive argument in the trade journals. > George Morrow said, "Why don't we get the clothing industry to make > shirt pockets 5.25 inch?" > > Dysan did not want such an extreme retooling, so they were pushing the > 3.25", which was basicaally a smaller 5.25", with a metal hub. They > reasoned that whichever size had the most software would end up being the > winner. So, Dysan set up an enormous software publishing venture. Before > there were any machines using 3.25", you could purchase most of the major > software packages on 3.25" disks! I ended up with a few drives and disks > from Micropro. > > But, then HP and Apple both went with 3.5". > When IBM went with 3.5" (PS/2, PC-DOS 3.20), the coffin was nailed shut. > Seequa Chameleon 325 seems to have been the only machine that made it to > market with 3.25" drives. > > Dysan had invested so much into their software publishing venture to > promote 3.25" that, when 3.25" died, they couldn't ever recover. R.I.P. > > > -- > Grumpy Ol' Fred ci...@xenosoft.com I make an official motion that Fred write his own "Everything I Know About Floppy Disks" page / book /encyclopedia. I suspect that what is inside his head is the greatest collection of knowledge about floppies on the planet. Fred, you will be paid with great admiration and appreciation. Sorry, all I can offer. :-) Anyone with me? Will If you want to build a ship, don't drum up people to collect wood and don't assign them tasks and work, but rather teach them to long for the endless immensity of the sea. Antoine de Saint-Exupery
[cctalk] Re: Friden (was Silly question about S-100 and video monitors)
> On 09/02/2023 8:50 AM CDT Peter Corlett via cctalk > wrote: > > > On Fri, Sep 01, 2023 at 04:32:57PM -0600, ben via cctalk wrote: > [...] > > I think that way has been for a while. Having a hard time finding a 68B50 Unicorn Electronics has the 68B50 for $7.99 https://www.unicornelectronics.com/IC/6800.html Will If you want to build a ship, don't drum up people to collect wood and don't assign them tasks and work, but rather teach them to long for the endless immensity of the sea. Antoine de Saint-Exupery
[cctalk] Re: Silly question about S-100 and video monitors
> On 09/01/2023 12:42 PM CDT Chuck Guzis via cctalk > wrote: > > > On 9/1/23 10:23, Will Cooke via cctalk wrote: > > They made pistols: > > https://www.popularmechanics.com/military/weapons/a23340620/singer-sewing-machine-company-45-pistol-gun/ > > > I love these seeming corporate mismatches. You know, Exxon purchasing > Zilog (and a number of other unrelated businesses). My favorite was > Ex-cell-o, starting business as a machine tool maker, making waxed-paper > milk cartons and purchasing disk maker Bryant. > > But then we also have Ball Brothers, they of the canning (Mason) jars, > going into aerospace and making OEM "kit" monitors... > > --Chuck My favorite is Votrax (speech synthesizers) being a division of Federal Screw Works. Will If you want to build a ship, don't drum up people to collect wood and don't assign them tasks and work, but rather teach them to long for the endless immensity of the sea. Antoine de Saint-Exupery
[cctalk] Re: Silly question about S-100 and video monitors
They made pistols: https://www.popularmechanics.com/military/weapons/a23340620/singer-sewing-machine-company-45-pistol-gun/ Will > > On 9/1/23 09:02, Tony Duell via cctalk wrote: > > >> The keyboard was from a surplus Singer data entry machine ( I thought they > >> only made sewing machines ).
[cctalk] Re: PDP-8/L $15,000
> On 08/28/2023 3:48 PM CDT Paul Koning via cctalk > wrote: > > Lander, in FOCAL? The only one I know is for the GT40, in assembler. > > paul Apparently the original version was in FOCAL. https://www.cs.brandeis.edu/~storer/LunarLander/LunarLander.html Will
[cctalk] Re: Signetics N8220B ??
> On August 28, 2023 8:24 AM CDT Holm Tiffe via cctalk > wrote: > > > Hi guys, > I have 8 "new" Chips from Signetics, they are labeled: > > S7536 > N8220B > > and on the backside between the pins "8220". > > Does anyone know what they do? My search with google and > in the 1976 Signetics Date Manual (from Bitsavers) wasn't helpful... > > Thanx in advance, > > Holm > > -- > Technik Service u. Handel Tiffe, www.tsht.de, Holm Tiffe, > Goethestrasse 15, 09569 Oederan, USt-Id: DE253710583 > i...@tsht.de Tel +49 37292 709778 Mobil: 0172 8790 741 >From the 1973 databook it appears to be a content addressable memory. http://bitsavers.trailing-edge.com/components/signetics/_dataBooks/1973_Bipolar_Memory.pdf Will I do not think you can name many great inventions that have been made by married men. Nikola Tesla
[cctalk] Re: Talking PDP11
> On 07/11/2023 9:59 AM CDT Paul Koning via cctalk > wrote: > But, judging by Wikipedia, the earlier Synclavier models were not digital > sampled waveform synthesizers but rather FM synthesizers. So I still wonder > if anyone did it earlier than Sherwin. > > paul Possibly the Computer Music Inc Melodian? https://en.wikipedia.org/wiki/Sampler_(musical_instrument)#:~:text=The%20Melodian%20was%20a%20monophonic,such%20as%20an%20ARP%202600. Will
[cctalk] Re: Talking PDP11
> On 07/09/2023 1:46 PM CDT Douglas Taylor via cctalk > wrote: > > > I was surprised to see that it took ~34 ms to run through all the > numbers from 0-, that is about 34 Hz. The manual says the 'settling > time' is 6 microseconds. Is this fast enough for audio? > > How would you convert a modern audio file into 12 bit integers? > > Doug If you put out 4096 samples in in 34 ms, that means you are putting out ~139,000 samples per second. Telephone audio is generally 8000 samples per second. CD quality is 44,100. So you can easily put samples out fast enough. If you just feed a bitstream to the DAC you shouldn't have any problems. If you try to do any processing in between, ymmv. There are various programs around that will convert different audio media to just about anything. Take a look at Audacity. I "think" it will do what you want. https://www.audacityteam.org/ It's cross platform, but I don't think PDP-11 is one of the ones it runs on :-) Will
[cctalk] Re: BEWARE: Phishing
> On 07/08/2023 8:36 AM CDT Alexander Schreiber via cctalk > wrote: > > > On Sat, Jul 08, 2023 at 12:49:43PM +1000, Doug Jackson via cctalk wrote: > > To be completely honest, Electrotechnology students with 415v DC bench > > supplies and HV caps all learnt very quickly not to catch something when > > somebody threw it to you. > Old electricians wisdom: "Be wary of honking great capacitors, lest they > bite thee in the arse" ;-) > > > http://wrcooke.net/electronics/ten_commandments.html
[cctalk] Re: PCs Limited XT
> On 06/14/2023 4:47 PM CDT Bill Degnan via cctalk > wrote: > > > Obviously I opened the box. So Inguess the Turbo board is just > "motherboard" > Bill > Back in those days I made my living assembling and repairing those XT machines. The motherboards were almost universally from a handful of manufacturers and generally referred to as "Turbo Motherboard XT." I never saw any type of daughterboard. Generally they had a switch that selected "normal" (4.77 mhz) or "turbo" (8 or 10 or rarely 12 mhz.) Is this message you are getting a bios message or is it from dos trying to load? If it is bios, it is something I have never seen. If it is from dos, it should be easy to get around it. The bios on almost all of them was either ERSO, Award, or Phoenix. But my memory is starting to fade after 35 years. Will
[cctalk] Re: Did Bill Gates Really Say That?
> On 06/14/2023 12:58 PM CDT Bill Degnan via cctalk > wrote: > > As far as the Bill Gates quote, I do remember reading an actual longer > quote somewhere (?), the context was lost from a larger paragraph if one > takes just the snippet statement IIRC. > Maybe the longer quote was "I never said no one will ever need more than 640K." ;)
[cctalk] Re: IBM RT Graphics
> On 06/07/2023 1:26 PM CDT Jonathan Katz via cctalk > wrote: > > > Hello! > > I have an IBM 6152 aka IBM RT system I rescued. (It may be a 6151?) > I'm 90% sure it has colour graphics. The system does seem to POST > correctly (according to the LED on the front) but the CRT is dead. I'm > wondering if anyone has built an adapter to hook this to a VGA > monitor. > > I'm a bit confused by the pinout. It has high and low bits for the RGB > (and associated grounds for each colour.) So I'm not sure how that > would work hooking to a more modern monitor. > http://bio.gsi.de/DOCS/IBM/615x/faqshard.html > > Otherwise I need a crash course in fixing CRTs. > > -- > -Jon > +44 7792 149029 I am not familiar with any of that equipment, but from the description here http://bio.gsi.de/DOCS/IBM/615x/faqshard.html#h33. it appears the video is two bits of ttl level data for each color. That is how EGA did it, which I think was about the same time frame (1985 ish.). The scan rates seem rather close to EGA as well. It might be worthwhile to look into EGA interfacing. Will
[cctalk] Re: VT180
> On 06/02/2023 10:56 AM CDT John Floren via cctalk > wrote: > > > Anyone on the list have a VT-180 a.k.a "Robin"? I got one for free a while > back, but no disks. Wondering if anyone's in a position to make copies of > their working disks and mail them to me -- I could have blanks sent, of > course. I'm in the SF bay area. > > john I don't have a VT-180 or disks, but I think you can find disk images at this link: http://www.gaby.de/sysdisk.htm In the list it says the Robin disk is in the archive, listed underneath the Rainbow. Download the archive and look in the 1997 directory. The file robn-cpm.td0 "should" be the boot disk image. Will I do not think you can name many great inventions that have been made by married men. Nikola Tesla
[cctalk] Re: Getting floppy images to/from real floppy disks.
> On 05/31/2023 3:33 PM CDT Mike Katz via cctalk wrote: > > > I think I will just convert file sizes to lengths of paper tape for > comparison: > > 1K 102.4" > 10K 85' > 100K 853' > 1M 1.6 Miles > 10M 16.5 Miles > 100M 165 Miles > 1G 1,695 Miles > 10G 16,947 Miles > 100G 6.8 Earth Circumferences > 1T 69.8 Earth Circumferences > NSA's intel on US citizens (that they don't collect): 37 AU Googles intel on World citizens (that they don't collect): 419 LY Will
[cctalk] Re: Getting floppy images to/from real floppy disks.
> On 05/25/2023 11:13 AM CDT Mike Katz via cctalk wrote: > > > Chuck, > > I agree with you that well written and commented C is the way to go. > > The advantage to an IDE comes with debugging and easy access symbols and > variables. > Some IDEs can be convinced to use standard makefiles. I have used Eclipse that way. So you still have fully buildable (and maintainable) code should an "upgrade" break stuff or the tool becomes unavailable. Eclipse is a a java dog and keeping it up to date between versions is a pain, but in my experience the benefits Mike mentioned are well worth it. Will
[cctalk] Re: Looking for datasheet of RTC M3001 ...
> On 04/12/2023 8:26 AM CDT Bernd Kopriva via cctalk > wrote: > > > Thanks for the link ... > ... i will ask him if this my help. > > Thanks Bernd > It may also be useful to contact the CS/EE department(s) at ETH and ask them. Perhaps they have a copy archived with the project documents. Will
[cctalk] Re: on the origin of home computers
> On 03/09/2023 1:24 AM CST Steve Lewis via cctalk > wrote: > > > Thank you all for the notes (and feedback). > > The 1964 skit of Patty Duke using that Univac-422 - all the markings of a > personal computer right there, no doubt. But dragging that into a home > doesn't make it a home computer. As engineers, sure, we're good with that > - I don't even put cases on my computers. Air flow, p, overrated. > Unless the AC cuts out in the summer. > > Steve, I think the video is very good and much needed. You and your daughter deserve kudos for it. When I was watching it I had the urge to do what others have done -- sharpshoot it from my perspective. Then I remembered who the intended audience was and changed my perspective. With that change I realized it was spot on. Would I have done it different? Sure. But that doesn't make mine "right" and yours "wrong." If your video gets ten young(er) people interested they can join some mailing list like this in the future and argue endlessly about which one was "first." So, congratulations to you and your daughter. It's a very nice video. Will
[cctalk] Re: on the origin of home computers
> On 03/08/2023 2:42 PM CST Sellam Abraham via cctalk > wrote: > > > On Wed, Mar 8, 2023 at 12:40 PM Will Cooke via cctalk > wrote: So, how do we get them interested? I > > can't think of a better idea than asking one of the few that IS > > interested. Can you? > > But ask them what exactly? > > Sellam Some variation of "what is it that makes this interesting to you?"
[cctalk] Re: on the origin of home computers
> On 03/08/2023 2:21 PM CST Sellam Abraham via cctalk > wrote: > > > On Wed, Mar 8, 2023 at 11:55 AM Will Cooke via cctalk > wrote: > > > > > > On 03/08/2023 11:59 AM CST Tarek Hoteit via cctalk < > > cctalk@classiccmp.org> wrote: > > > > > > We probably need to get more advice from her on what we all, old-school > > timers, should do to help keep the legacy going on ! > > > > > > Regards, > > > Tarek Hoteit > > That statement may be the most important one on this list in a long, long > > time. > > Will > > Huh? That makes less than zero sense. > > We're already doing what we're doing. She should be asking US what SHE > should do to preserve the legacy we've carried on to her and her generation. > > I mean, is anyone actually serious about asking Greta how to save the > planet? > > Don't abdicate your responsibilities as an experienced adult over to > inherently naive children. > > Sellam Everyone on this list is going to die sometime. Some sooner than later. We need young people if all or any part of this history is going to be preserved past us. All of the "museum" fiascos that have been covered here show how easily it is lost. But as Tarek mentioned in his follow up, very few young people are interested. So, how do we get them interested? I can't think of a better idea than asking one of the few that IS interested. Can you? Will
[cctalk] Re: on the origin of home computers
> On 03/08/2023 11:59 AM CST Tarek Hoteit via cctalk > wrote: > > We probably need to get more advice from her on what we all, old-school > timers, should do to help keep the legacy going on ! > > Regards, > Tarek Hoteit > That statement may be the most important one on this list in a long, long time. Will
[cctalk] Re: Wanted: Apple III 5MB Profile HD driver file
> On 02/21/2023 10:48 PM CST Eric Smith via cctalk > wrote: > > Profile trivia: > > The firmware _inside_ the Profile is strange in that it doesn't actually > KNOW the size of the Profile it's installed into. At power up, when the > drive reads the home block, the drive size is stored there. That's done > when the drive is formatted. There is different formatter firmware for 5MB > and 10MB drives. I think that was rather common with early SASI/SCSI controller boards that were separate from the drive. My Ampro Little Board Plus docs talk about certain controllers that saved the drive parameters in a reserved sector and some that did not. I believe it couldn't boot from ones that did not. My guess would be that Apple used separate controller boards and drives in the Profile. But that's simply a guess. Will
[cctalk] Re: Store with "vintage" computers and parts
> On 02/10/2023 9:53 AM CST Sellam Abraham via cctalk > wrote: > > > DDG is just a Google fish bowl. Same data set, similar results. > > If you're concerned about privacy, there are much better options available. > > Sellam > I would be interested in knowing some of those options. Thanks, Will
[cctalk] Re: Store with "vintage" computers and parts
Ouch! Thanks to everyone who spotted its a scam. Sorry for not checking closer before posting. Will > On 02/09/2023 2:03 AM CST Tom Hunter via cctalk wrote: > > > Avast claims the site is infected with a trojan. > The contact address does not exist: 4144 Fannie Street Houston, Texas 77063 > United States > Stay away! > > On Thu, Feb 9, 2023 at 2:59 PM Sellam Abraham via cctalk < > cctalk@classiccmp.org> wrote: > > > This is an item I had listed on eBay for a couple years, and which sold on > > eBay a few months ago ==> > > https://www.bryanipad.shop/product/dsp-225-tempest-ink-jet-printer-hp-2225a-thinkjet-in-rf-shielded-enclosure-737796124001173505.html > > The photos and description are mine, from my eBay ad. > > This is definitely a scam. > > Sellam > > On Wed, Feb 8, 2023 at 8:21 PM Steven Shumaker via cctalk < > > cctalk@classiccmp.org> wrote: > > > interesting! Some of the items looked really familiar so I did some > > > quoted text searches on EPay. They were exact matches for some highly > > > unique listings > > > who is scamming who here... > > > Steve > > > > > > > > > On 2/8/2023 7:47 PM, Glen Slick via cctalk wrote: > > > > On Wed, Feb 8, 2023 at 7:17 PM Will Cooke via cctalk > > > > wrote: > > > > > This place may be of interest. Most of the stuff they have for sale > > > probably isn't of much interest here, but there are a few gems. The link > > > takes you to one, which is how I found it. > > > >> > > https://www.bryanipad.shop/product/microlog-corporation-atr-6800-vintage-rare-738148146177114113.html > > > > > > > > > Very skeptical that this site is legitimate. > > > > "Free Shipping & Returns: Free Shipping for all orders. Free Return" > > > > Uh, no way, no how. > > > > Reviews are just some Lorem Ipsum text. > > > > 1 Review For Chaz Kangeroo Hoodies > > > > Admin - 30 Nov, 2018 > > > > Aliquam fringilla euismod risus ac bibendum. Sed sit amet sem varius > > > > ante feugiat lacinia. Nunc ipsum nulla, vulputate ut venenatis vitae, > > > > malesuada ut mi. Quisque iaculis, dui congue placerat pretium, augue > > > > erat accumsan lacus I do not think you can name many great inventions that have been made by married men. Nikola Tesla
[cctalk] Store with "vintage" computers and parts
This place may be of interest. Most of the stuff they have for sale probably isn't of much interest here, but there are a few gems. The link takes you to one, which is how I found it. https://www.bryanipad.shop/product/microlog-corporation-atr-6800-vintage-rare-738148146177114113.html Not affiliated in any way. Just thought it might be of interest. Will
[cctalk] Re: Computer Museum uses GreaseWeazle to help exonerate Maryland Man
> On 02/03/2023 8:25 AM CST Paul Koning via cctalk > wrote: > It's puzzling that temperature would matter. Obviously, when you hit the > Curie temperature the data goes away, but for typical magnetic materials that > is in the hundreds of degrees. Does the hysteresis curve shift enough at > moderate temperatures (a bit over room temperature) to matter? > > paul Yes. The thresholds shift with temperature. Some companines (DEC?) used temperature-compensated amplifiers to address the issue. IBM, on some models like the 1620, kept the cores at a constant (elevated) temperature. https://en.wikipedia.org/wiki/Magnetic-core_memory#Physical_characteristics Will I do not think you can name many great inventions that have been made by married men. Nikola Tesla
[cctalk] Re: Core memory (was Re: Computer Museum uses GreaseWeazle to help exonerate Maryland Man)
> On 02/02/2023 10:03 AM CST Sellam Abraham via cctalk > wrote: > > > This discussion on core memory got me thinking: > > Is it possible to "read" core memory by examining each core using some kind > of instrument that would sense its "charge" (or lack thereof) > non-destructively? > > Could a piece of paper be placed over a core plane and fine particles of > iron sprinkled onto the paper to literally "see" the bits? > > Please excuse me for any ignorant assumptions made here on my part. > > Sellam I suspect it would be possible, but not easy. The main reason I say that is that the toroidal shape of the cores, rather than something like a square or straight bar, is intended to keep the magnetic field contained within the ring. Instead of coming out an end or edge and going through free space, the magnetic lines of force go circularly around the loop. The polarity of the field determines whether it is clockwise or counterclockwise. So very little field escapes. That's what makes it possible to have them packed so tightly without interference. https://en.wikipedia.org/wiki/Toroidal_inductors_and_transformers Will
[cctalk] Re: Computer Museum uses GreaseWeazle to help exonerate Maryland Man
> On 02/01/2023 3:51 PM CST Paul Koning via cctalk > wrote: > ot sure about that. What sort of numbers are we talking about? > > If all else fails there's core memory, which as far as I remember is pretty > much unlimited for both read and write. > > paul I don't know for sure and can't find any references, but I strongly suspect that core memory would wear out over time, as well. My reasoning for this is the because in principle it works the same as FRAM. I usually refer to FRAM as "core on a chip." Over time, the magnetic domains in FRAM tend to stay in one polarization or another. I see no reason why the magnetic domains in core wouldn't do the same. However, a single core is probably bigger than the entire FRAM chip so there are a LOT more domains. That means it would take a proportional amount of writes to wear out -- let's just say a million times. In addition, core access was in microseconds, whereas FRAM and other modern memories are in nanoseconds. So it takes something like 1000 times longer on the clock on the wall to perform the same number of writes. So in the end something like a billion times longer on the calendar to wear it out. I would be very interested if anyone actually knows and especially if there are references available. Will
[cctalk] Re: DLOAD BASIC command for Color Computer 1/2 heritage
> On Monday, January 30, 2023, 01:02:16 AM EST, Jim Brain via cctalk > wrote: > > Over at the CoCo Mailing List, there's a archeological discussion about > the DLOAD BASIC command in older versions of the Color Computer BASIC. > It uses the serial port (and no doubt was designed for computer sharing > in classrooms or similar), but the questions are around how it was > designed and what inspiration is drew from. > > I infer MS wrote the code, and the protocol includes: > > P.ACK - Acknowledge - C8 hex. > P.ABRT - Abort - BC hex. > P.BLKR - Block request - 97 hex. > P.FILR - File request - 8A hex. > P.NAK - Negative Acknowledge - DE hex. > > Does that look like any protocol anyone has seen before? > > Jim According to this article: http://www.trs-80.org/network-4/ Radio Shack's Network 4 was based on Corvus Omninet. So perhaps the earlier Color Computer commands were too? Will
[cctalk] Re: Computer Museum uses GreaseWeazle to help exonerate Maryland Man
> That was a common practice in those days. I remember seeing news stories > about it. I "think" a law was passed in late 80s forbidding that. A lot of > products now say "this box was (proudly) made in the USA. > Will https://www.ftc.gov/business-guidance/resources/complying-made-usa-standard#qualified Third example under. U.S. origin claims for specific processes or parts Apparently passed in 1997. Will
[cctalk] Re: Computer Museum uses GreaseWeazle to help exonerate Maryland Man
> On 01/27/2023 3:00 PM CST Bill Gunshannon via cctalk > wrote: > > > On 1/27/2023 3:53 PM, Fred Cisin via cctalk wrote: > >>> and IBM sold what seems to be a re-badged Epson MX-80, > > > > On Fri, 27 Jan 2023, Bill Gunshannon via cctalk wrote: > > > Yes, I always got a kick out of these. Came in an IBM box labeled > > > "Made in > > > USA". The only thing "Made in USA" was the box. > > So, it was honest to label the box, "Made in USA"? > > Apparently. They did it for years until Epson started manufacturing > over here. > > > bill That was a common practice in those days. I remember seeing news stories about it. I "think" a law was passed in late 80s forbidding that. A lot of products now say "this box was (proudly) made in the USA. Will
[cctalk] Re: Computer Museum uses GreaseWeazle to help exonerate Maryland Man
> On 01/27/2023 8:41 AM CST geneb via cctalk wrote: > > > > ... my freshman year of HS. I was the only guy > in a room full of girls ... > > g. > And the downside of this was...? Will
[cctalk] Re: Philips P2000C add-ons.
> On 01/24/2023 11:09 AM CST Tony Duell via cctalk > wrote: > > > A couple of questions if anyone has experience of this machine : > > 1) There is a 5 pin DIN socket for connecting an external video > monitor. The signals seem to be TTL-level separate syncs at European > TV rates (15625Hz horizontal, 50Hz vertical) and separate (not > composite) 4-level analogue video. > > I believe Philips sold a 12" monitor to connect there. What was the > model number? Is a service manual availabe? > > Has anybody linked other monitors to that socket? > In the US in the late 80s and 90s, there were a crap ton of similar monitors (without case) sold on the surplus market. I had one. I believe they were mostly Mitsubishi / Panasonic. Most of them were 9" with a lesser number of 12". They had an edge connector for the power, ground, H sync, V sync, and video inputs. Of course, in the US, they were 15750 / 60 Hz sync. I can only guess what their original purpose was, but they were easy to connect to a PC RGB video card (four resistors got you 16 gray shades.) So that interface wasn't too uncommon. Perhaps there is/was something similar available on the other side of the pond? Maybe the reason you can't find any trace of the Philips add-on is for the same reasons you suggest -- marketing realized it was of little value prior to releasing it. > 2) There is a 50 pin card edge for a SASI interface. I think the > Philips hard disk unit used the Xebec S1410 controller. I've > downloaded the user manual for that from bitsavers which at least > gives me the command set. > > Does anyone have experience of a SASI-flash memory interface? Any > recomendations for things to look at? Or should I design my own, it > doesn't appear too hard? > I have an Ampro Little Board Plus, which is a single-board Z80 computer the size of a 5 1/4" disk drive. The "plus" means it has a SCSI interface. A couple of years ago I was planning to build a flash disk for it and dug through a lot of specs and bios code. Original SCSI was almost identical to SASI and they were often interchangeable. The protocol is rather simple, as you stated. What I found in the Ampro bios code was that for reading and writing only about 4 commands were used. Another small number were used for formatting. I think, iirc, there were two types of read and two types of write. I never got around to building the thing, but it should be pretty simple. I would also be rather surprised if no one else has done it. But if you have the P-2000 bios code, you could take a look. I suspect it would be very similar to the Ampro code. Will
[cctalk] Re: IBM PC/XT and NEC "gold" tam
> On 01/21/2023 2:55 PM CST Fred Cisin via cctalk wrote: > The first 5150 was available with one row of 16K RAM, you could plug > whatever you had (such as from Godbout) into the other 3 rows, and almost > anything was cheaper than IBM's prices. > > > I think that the early 5160 also used 16K RAM, but I don't know if you > could buy one without all 4 rows populated. > > Then 5160 was available that could use 64K RAM chips, and/or, with a > trivial mod could use two rows of 256K chips, plus two rows of 64K chips. > > Anybody remember the full details? > That all sounds correct. In addition, I seem to recall there were some even later 5160s that came from the factory with the 640K "mod." I just opened the 5160 I have to look at it. It's crammed full of boards that I didn't want to pull, but I could see it has four rows of what look like 64K chips. The board is marked "64 / 256K " and it has some RAM on at least one of the plug-in boards. I really should sell this monster before I get too old to lift it. Will
[cctalk] Re: AI applied to vintage interests
Coincidentally, I just saw this article on CNN: https://www.cnn.com/2023/01/19/tech/chatgpt-future-davos/index.html I think it says more about the state of education, even among the "elite," than it does about the state of "AI." But that's just me. Will
[cctalk] Re: PT-68K
I should probably put the right parts in. https://circuitcellar.com/cc-blog/ciarcia-onward-upward/ "Let me warn any budding entrepreneurs that these four events test your gambling tactics more than your business acumen. In my case, Ciarcia’s Circuit Cellar was the product 30 years ago, along with the supporting manufacturing company. It grew quickly and afforded certain luxuries (e.g., Porsches, BMWs, Ferraris, etc.) typically necessary in our culture to designate achievement. Too little business was not an issue. The “too much business” event happened right after the introduction of the IBM PC. Circuit Cellar was the third company in the country to market an IBM PC clone. I thought it was a good idea. Everybody who couldn’t get a real IBM PC started banging on our door for an MPX-16. We got $1 million in orders in just a few weeks! What was I supposed to do? Certainly not what 99% of you would have done—I stopped taking orders!" > On 12/28/2022 6:42 PM CST Will Cooke via cctalk wrote: > > > > On 12/28/2022 6:21 PM CST Chris via cctalk wrote: > > > > > > I do seem to recall some off the wall looking case in the articles. I'm not > > going to reread them right now. I was under the misconceived assumption > > these would all be foumd in such a case. > > > Apparently they sold a LOT of them, according to Steve in this article: > Let me warn any budding entrepreneurs that these four events test your > gambling tactics more than your business acumen. In my case, Ciarcia’s > Circuit Cellar was the product 30 years ago, along with the supporting > manufacturing company. It grew quickly and afforded certain luxuries (e.g., > Porsches, BMWs, Ferraris, etc.) typically necessary in our culture to > designate achievement. Too little business was not an issue. > > Will I do not think you can name many great inventions that have been made by married men. Nikola Tesla
[cctalk] Re: PT-68K
> On 12/28/2022 6:21 PM CST Chris via cctalk wrote: > > > I do seem to recall some off the wall looking case in the articles. I'm not > going to reread them right now. I was under the misconceived assumption these > would all be foumd in such a case. > Apparently they sold a LOT of them, according to Steve in this article: Let me warn any budding entrepreneurs that these four events test your gambling tactics more than your business acumen. In my case, Ciarcia’s Circuit Cellar was the product 30 years ago, along with the supporting manufacturing company. It grew quickly and afforded certain luxuries (e.g., Porsches, BMWs, Ferraris, etc.) typically necessary in our culture to designate achievement. Too little business was not an issue. Will
[cctalk] Re: PT-68K
Yeah, I know it's just one page of one article of a series of them. The rest are in the pages of Byte, which are on the same web site. There is also a story about it on the web, written by Steve. With the name and date from that one page, a quick search turns up lots of stuff. > On 12/28/2022 4:02 PM CST Chris via cctalk wrote: > > > That's only page 1 lol. > > Artwork for the board/s never was published as I recall. I wonder if he still > has it. > On Wednesday, December 28, 2022, 04:58:34 PM EST, Will Cooke via cctalk > wrote: > > > > > On 12/28/2022 3:36 PM CST Chris via cctalk wrote: > > > > > > What was the name of Steve Ciarcia's outfit, Micromint? I see no entries > > for that. That bizarro-world IBM compatible he offered years ago is insane > > enough to love. Want to build me one. > His company was Micromint. The computer was the MPX-16 > > https://worldradiohistory.com/hd2/IDX-Consumer/Archive-Byte-IDX/IDX/80s/82-83/Byte-1982-12-OCR-Page-0044.pdf I do not think you can name many great inventions that have been made by married men. Nikola Tesla
[cctalk] Re: PT-68K
> On 12/28/2022 3:36 PM CST Chris via cctalk wrote: > > > What was the name of Steve Ciarcia's outfit, Micromint? I see no entries for > that. That bizarro-world IBM compatible he offered years ago is insane enough > to love. Want to build me one. His company was Micromint. The computer was the MPX-16 https://worldradiohistory.com/hd2/IDX-Consumer/Archive-Byte-IDX/IDX/80s/82-83/Byte-1982-12-OCR-Page-0044.pdf
[cctalk] Re: PT-68K
> On 12/27/2022 9:57 PM CST Will Cooke via cctalk wrote: > > > > On 12/27/2022 9:52 PM CST Bill Degnan via cctalk > > wrote: > > > > > > Which issue of Radio Electronics? > > Bill > > > I don't know which issues it's in, but they are all here: > https://worldradiohistory.com/Radio_Electronics%20_Master_Page.htm They appear to start in Oct 87 and there is one article on DRAM for it as late as June 88. https://worldradiohistory.com/Archive-Radio-Electronics/80s/1987/Radio-Electronics-1987-10.pdf
[cctalk] Re: PT-68K
> On 12/27/2022 9:52 PM CST Bill Degnan via cctalk > wrote: > > > Which issue of Radio Electronics? > Bill > I don't know which issues it's in, but they are all here: https://worldradiohistory.com/Radio_Electronics%20_Master_Page.htm
[cctalk] Re: PT-68K
> On 12/27/2022 9:36 PM CST Chris via cctalk wrote: > > > Those are for a different board. Maybe close enough? > If you read the description it says the only difference is the clock chip, which I believe is "fully" compatible.
[cctalk] Re: PT-68K
boot eprom download -- scroll down https://peripheraltech.com/PT68K1A.htm > On 12/27/2022 9:04 PM CST Chris via cctalk wrote: > > > What will you do for firmware? I do believe the developer was around, maybe > still is. But wanted an enormous amount of money. > On Tuesday, December 27, 2022, 09:58:51 PM EST, Jim Brain via cctalk > wrote: > > On 12/27/2022 8:47 PM, Chris via cctalk wrote: > > It's a IBM PC form factor 68000 based project that was featured in Radio > > Electronics. Anyone remember it or even know what I'm talking about? It > > would be a fun prokect. > I remember it, and I believe I have all those issues, as a project to > complete at some point. > > Jim > > -- > Jim Brain > br...@jbrain.com > www.jbrain.com I do not think you can name many great inventions that have been made by married men. Nikola Tesla
[cctalk] Re: PT-68K
http://peripheraltech.com/PT68K2 > On 12/27/2022 8:58 PM CST Jim Brain via cctalk wrote: > > > On 12/27/2022 8:47 PM, Chris via cctalk wrote: > > It's a IBM PC form factor 68000 based project that was featured in Radio > > Electronics. Anyone remember it or even know what I'm talking about? It > > would be a fun prokect. > I remember it, and I believe I have all those issues, as a project to > complete at some point. > > Jim > > -- > Jim Brain > br...@jbrain.com > www.jbrain.com I do not think you can name many great inventions that have been made by married men. Nikola Tesla
[cctalk] Re: looking for a laptop
> On 12/22/2022 10:55 PM CST Chris via cctalk wrote: > > > Anyone partimg with some dang-old thing? It has to work. I'm leaning towards > a mono screen. I'm leaning against Zeniths, got 2 Minisports. But anything is > possible. > > IBM produced a Kanji subbish laptop some years ago. I want to say it had a > 286. Anyone know? Hi Chris, I have a couple of 386sx laptops I'm pondering getting rid of. I would have to dig them out to give you all the details. Contact me off list if interested. Will I do not think you can name many great inventions that have been made by married men. Nikola Tesla
[cctalk] Re: [SPAM] Re: what is on topic?
> On 12/22/2022 8:45 PM CST Glen Slick via cctalk > > Shirley none of you are serious about a 32-bit (at least partially) > operating system being able to execute on a 286 processor. > > You couldn't even run Windows 3.1 in Enhanced mode on a 286 processor. > > > Well, there's always Linux on an 8 bit microcontroller... https://hackaday.com/2012/03/28/building-the-worst-linux-pc-ever/ Will I do not think you can name many great inventions that have been made by married men. Nikola Tesla
[cctalk] Re: Replacing NiCd with NiMH in a pro way.
> On 12/22/2022 4:34 PM CST Chuck Guzis via cctalk > wrote: > > That's not to say that Li-ion cells are without their quirks. I > recently almost discarded a AA-sized 14500 cell because the output > voltage had suddenly dropped to the point where none of my chargers > would even see it. So I put it on a corner of my workbench against the > time when I had accumulated several and could turn them in for > disposal. A couple of days ago, I picked up the cell and checked it > with my voltmeter and it read 3.5V. Put it in the charger, and slowly > charged to capacity. What happened during the month or so that it sat > on my workbench, I cannot say. > > --Chuck A VERY large percentage of LiIon batteries have a protection circuit built in to prevent over-discharge. Even a lot of the "standard" cell types (e.g. 18650s) The circuit disconnects the battery from its terminals if the voltage drops too low, showing near 0 volts out. If it just barely meets the cutoff, it may recover enough to re-activate the circuit, making it possible to recharge it. Often, you can open the case, skip over the circuit board to access the battery cell directly, and add a small amount of charge to reactivate it. Then it will work normally. I've done this a few times. Will I do not think you can name many great inventions that have been made by married men. Nikola Tesla
[cctalk] Re: Replacing NiCd with NiMH in a pro way.
> On 12/22/2022 2:33 PM CST Chuck Guzis via cctalk > wrote: > > > I haven't run across a single IC dedicated to the > process yet--I suspect there must be one out there somewhere. > > FWIW, > --Chuck There are quite a few. Mouser lists 278 that claim NiMh capability. All but 9 of those are multi-chemistry. https://www.mouser.com/c/semiconductors/integrated-circuits-ics/power-management-ics/battery-management/?battery%20type=Alkaline%2C%20NiCd%2C%20NiMH%7C~Lead%20Acid%2C%20LiFePO4%2C%20Li-Ion%2C%20Li-Polymer%2C%20Li-Phosphate%2C%20NiCd%2C%20NiMH~~Lead%20Acid%2C%20NiCd%2C%20NiMH%7C~LiFePO4%2C%20Li-Ion%2C%20Li-Polymer%2C%20NiCd%2C%20NiMH%2C%20SuperCap~~LiFePO4%2C%20Li-Ion%2C%20Li-Polymer%2C%20NiMH%7C~Li-Ion%2C%20Li-Polymer%2C%20NiCd%2C%20NiMH%7C~Li-Ion%2C%20NiCd%2C%20NiMH~~Li-Ion%2C%20NiMH%7C~NiCd%2C%20NiMH~~NiMH=Charge%20Management=semiconductors%2Fintegrated-circuits-ics%2Fpower-management-ics%2Fbattery-management%7C~Battery%20Type=pricing Will
[cctalk] Re: "Classic" RAM chips, #FREE, #RARE, #VINTAGE
> > I also have a selection of old PC CPUs ranging from 8088s and V20 compatible > to early Pentium and compatibles (e.g. AMD K6) If anyone is interested > contact me off list. I have about 15 total. I can do a quick inventory if > anyone is interested. > > Will The CPUs are now spoken for. But there is likely to be some more "treasure" buried around here, so don't go away :-) Will
[cctalk] Re: Replacing NiCd with NiMH in a pro way.
> On 12/22/2022 10:02 AM CST Cedric Amand via cctalk > wrote: > > > Hi Jim, Maybe this is specific to europe but NiCds are hard to come by here, > they are prohibited since 2008 And even more prohibited since 2017 ( they > also exclude medical equipment ) I used to source them in ex-ussr countries > but even there they are hard to come by nowadays, quite expensive, and > usually new old stock from 10+ years ago which hardly qualifies as renewing > your battery pack, even if it's usually better than the 40+ years batteries. > On top of that they are usually 700mAh, which isn't much by today's standards > I'll be trying to shove 2400mAh NiMH in my CE150, the question remains, do I > keep the NiCd trickle charge (many people did and seem to stil be alive) or > do I go the extra mile and use a proper NiMh charger ( that'll blink when > batteries are full and stop the charge ) You could also argue wether or not a > $1 nimh charger from Aliexpress does any good to my safety. I'm surprised > "replacing nicd with modern equivalents" doesn't seem to have much attention > Le 2022-12- 22 16:52, Hi Cedric, I can't answer your question either; I've dealt with the same dilemma on a few occasions. But as Jim mentioned, I have not had trouble getting NiCds here in the US (new from China.) However, the reason I'm posting is that there is a website with tons of good information on different battery types, including charging, that may or may not be of some use to you https://batteryuniversity.com/articles Perhaps you can find some info there that helps. Will
[cctalk] Re: "Classic" RAM chips, #FREE, #RARE, #VINTAGE
> On 12/22/2022 5:56 AM CST Will Cooke via cctalk wrote: > > > > I have an assortment of old dynamic RAM chips: > 1M x 1 approx 35 > 256K x 4 approx 40 to 50 > 256K x 1 approx 80 to 100 > The RAM chips are all spoken for. I also have a selection of old PC CPUs ranging from 8088s and V20 compatible to early Pentium and compatibles (e.g. AMD K6) If anyone is interested contact me off list. I have about 15 total. I can do a quick inventory if anyone is interested. Will
[cctalk] "Classic" RAM chips, #FREE, #RARE, #VINTAGE
I think my original message didn't go through (forgot to select plain text instead of html.) If it did I apologize for spamming the list. I'm clearing out some clutter so I can get to some more clutter to clear it out. Much of my clutter is classic computer related (at least by my definition.) But it needs to go. I have an assortment of old dynamic RAM chips: 1M x 1 approx 35 256K x 4 approx 40 to 50 256K x 1 approx 80 to 100 They are various speeds, mostly between 100ns and 150 ns If anyone wants them, let me know. You pay shipping. Otherwise they go to the landfill. You can contact me off-list. Will I do not think you can name many great inventions that have been made by married men. Nikola Tesla
[cctalk] Re: Identifying a Failed Diode in a Rainbow H7842 Power Supply
> On 11/26/2022 12:47 PM CST Rob Jarratt via cctalk > wrote: > > > Just trying to decide what to replace the failed diode with, and looking at > the UF400x series, as suggested by Mattis. It seems to me that as long as the > PIV is 200V or higher it should be fine from that point of view, the > switching speed is never higher than 70ns, while the original A114x (assuming > it *is* an A114x) has a switching speed of 200ns (possibly even 200us from > the datasheet). > > However, I am wondering about the forward voltage drop. The datasheets > suggest that the A114x parts have a 1.3V forward voltage drop. I have a spare > H7842 that was working (until I messed it up today, another story), so I > tested the diode in that, its forward voltage appears to be 0.5V, using a > little tester I have. The UF400x have ratings of either 1.0V or 1.7V. > > How sensitive is the circuit going to be to the forward voltage on the diode? > Given that the forward voltage of the suggested replacement is higher, would > it slow down the speed with which the transistor is switched off too much and > cause it to be overloaded and fail? > > Thanks > > Rob > > I'm not at all familiar with either this circuit or any of the mentioned diodes. However, I would point out that a diode's forward voltage drop varies with current through it. Usually, the datasheet will list the "max" forward drop, at the rated current and typically at the lowest rated temp (the drop decreases as temp rises.) So it is entirely possible that your tester is putting a very small current through a high-current diode and getting that 0.5V. It might be useful to feed it something close to its rated current and measure the drop for a more accurate estimate. Will
[cctalk] Re: 9-pin mini-DIN serial?
> On 09/15/2022 11:01 PM CDT Cameron Kaiser via cctalk > wrote: > > > Trying to identify two cables I ended up with, one to DE-9 and one to Mac > 8-pin > mini-DIN. The other end on both is a male 9-pin mini-DIN. These clearly look > like serial cables, but to what? A cursory Google didn't come up with anything > obvious. They don't fit the Mac GeoPort or Sun SPARC serial ports because the > pins are slightly out of place. > Possibly to an Epson PX-8. http://www.bitsavers.org/pdf/epson/PX-8/PX8-tech-manual.ch1.pdf https://www.ebay.com/itm/115323960568?chn=ps=415373727804=1=1=711-117182-37290-0=2=415373727804_115323960568=1263104805526=c==1025946==14859008593=130497710760=pla-1263104805526=9300678=586215512=Cj0KCQjwvZCZBhCiARIsAPXbajuD3HkJhRxVpydiFZWGvGqfFiH__CTdpmeWiefyr0Mv4EMIgG1OKDEaAgMgEALw_wcB Will
[cctalk] Re: VCF Swap Meet October 8, 2022 @ InfoAge
> On 09/11/2022 12:47 PM CDT Jeffrey Brace via cctalk > wrote: > > > The following info is found here: https://vcfed.org/vcf-swap-meet/, but I'm > pasting here for your reference. > Interesting. Unless I'm blind, nowhere in that email or the linked flyer does it state what city and state (or country) it's in.
[cctalk] Re: 8" disk question!
> On 09/02/2022 11:05 AM CDT geneb via cctalk wrote: > > > On Fri, 2 Sep 2022, Fred Cisin via cctalk wrote: > > > well, 720, not 7K > No, it was actually some absurdly huge number. It has something to do > with how the AS hardware & software was working out the RPM of the drive. > > g. My "guess" would be measuring/counting the time between index pulses and since it got to measure it twice in one revolution, the time between them was, say, 1/16th or so the normal time. Will You don't understand anything until you learn it more than one way. Marvin Minsky
[cctalk] Slightly off topic --Places to go in Huntsville
Next week I will be in the Huntsville, Al, USA area for an entire day with no commitments. Does anyone have recommendations on how to spend my day? I have been to the space and rocket museum several times. Any computer museums or displays, especially of space-related equipment? Any good surplus stores? All suggestions welcome. Thanks, Will You don't understand anything until you learn it more than one way. Marvin Minsky
[cctalk] Re: BBS memorabilia
In case you aren't aware of it, there was a bbs magazine. Just ran across this: https://archive.org/details/bbsmagazine Will You don't understand anything until you learn it more than one way. Marvin Minsky
[cctalk] Re: BBS memorabilia (fwd)
Apparently there was a BBS magazine. Just happened across this. https://archive.org/details/bbsmagazine Will You don't understand anything until you learn it more than one way. Marvin Minsky
[cctalk] Re: Old fashioned PCB layout images, red/blue
> On 07/31/2022 7:29 PM CDT William Sudbrink via cctalk > wrote: > > > Hi, > > > > What is the "correct" name for the style (technology?) of circuit board > layout images where the top is blue, the bottom is red and overlaps are > purple? Also, any silkscreen is black. I thought someone once told me that > there was an automated tool (maybe in KiCad?) that would produce Gerbers > from that type of image. Does anyone know of such a utility? > > > > Thanks, > > Bill S. > I originally sent this to the list, but it was rejected. So here it is again. You can import a graphics file into kicad and create a footprint / component from it. I have only used it to import an image to put onto the silkscreen so I don't know what all it can do. I'm using kicad 5.1.9 and from the main (initial) window click Tools -> Convert Image to bring up the image import tool. HTH, Will P.S. I also found this link that may be of interest: https://forum.kicad.info/t/copy-a-old-board-layout-into-kicad/26717/25
Re: Identifying an 1802 system
> On 05/15/2022 11:02 PM John Ball via cctech wrote: > > > I just received a machine that someone found at a Vancouver second hand > store that I basically told them to buy on the single fact I don't own any > COSMAC machines and I've now had a chance to take it apart and photograph > the boards. It seems to be some sort of a kit system that the previous owner > put into a custom enclosure along with a power supply, a cassette interface I suggest asking over at cosmacelf.com. There is a lot of Cosmac info and expertise there, not just about Elfs (elves?). One thing that comes to mind is a series of boards and kits that were developed by a Canadian user group that sounds much like you describe. Development of those were tracked in their newsletter, Ipso Facto: http://cosmacelf.com/publications/newsletters/ipso-facto/ Some of the people who developed those systems are members of the forum at cosmacelf.com. Will
Re: DEC H7822 power supply
> On 05/12/2022 2:14 PM Peter Coghlan via cctalk wrote: > > > Wayne S wrote: > >> On May 12, 2022, at 09:56, Peter Coghlan via cctalk > >> wrote: > >> > >> Toby Thain via cctalk wrote: > On 2022-05-11 7:02 p.m., Peter Coghlan via cctalk wrote: > Given the normal usage that has evolved for the terms DC and AC rather > than > their dictionary definitions, I would suggest that the current that gets > passed by a rectifier has both a DC component and an AC component. When > > >>> > >>> It does not, due to unidirectionality. > >>> > >> > >> Consider the current through the rectifier as the sum of a "DC" current > >> plus > >> an "AC" current. The "DC" current has a steady positive value and the "AC" > >> current varies above and below zero with a magnitude less than or equal to > >> that of the "DC" current. > > > > I’m really trying to understand what you’re getting at here. > > In practical terms, The assumption that there is a sum of a DC and AC > > component is incorrect. > Why? What evidence do you have that the assumption is incorrect? > > If I am trying to calculate the height a sea harbour wall needs to be, can I > not consider the height of the tide and the height of the waves separately > and add them together, just to make it easier to work it out even though I > know that it would be physically impossible to distinguish the water that > makes up the tide from the water that makes up the waves? > > (It's not even that bad in the case of electric current because instruments > exist which can measure the DC component of a current and the AC component > of a current separately or together.) > > Peter, You are quite correct. It is called superposition. https://en.wikipedia.org/wiki/Superposition_principle It applies to all linear systems and is one of the principles that make many difficult problems practicable. My background is primarily physics. Superposition is extremely important there in many realms, including signal processing, electric circuits, and differential equations, among many others. I'll say no more. I didn't want to get into this quagmire, either. Will
Re: Comtec model P135-20/35 Paper Tape Punch
I have done a quick and dirty scan of the manual. It is available here: http://wrcooke.net/comtec_p135_20_35_ppunch001.pdf Will
Re: Comtec model P135-20/35 Paper Tape Punch
> On 05/01/2022 2:28 PM Wayne S wrote: > > > Seconded. Punches have to be made to exact tolerances and should be made of a > very hard material, (because they can quickly become dull ) that requires > special machine tools to manufacture. > > Sorry, didn't mean to imply I would do it personally. That is beyond my abilities as well. I'm fortunate to have a close relative who is a machinist. But it's a moot question. AFter closer examination, the two extra solenoids are missing, so it can't punch 8 levels without adding those as well. Will
RE: Comtec model P135-20/35 Paper Tape Punch
> On 04/30/2022 2:09 PM amp1...@gmail.com wrote: > > > Hi Will, > > Is the punch you received capable of punching 8-level tape? While the PDF on > Surplus Sales of Nebraska's site says the unit can punch 5- to 8-level tape, > one of the photos on the site, > https://www.surplussales.com/Images/Equipment/Military/eqp-p135-20-35_2_lg.jpg, > makes it look like it can only punch up to 6-level tape. > > -- Ron > It appears that it can only punch 6 (or 5?) level tape the way it is configured. The manual isn't very clear on it, specifying repeatedly that it can punch 5 to 8 level tape. But the one I got only has 6 holes as in the picture. In the back of the manual the parts list specifies different "guide and die blocks." I haven't hooked mine up yet -- I need a 5 amp, 27 V supply. But it appears it has everything except the die block to work with 8 level. I doubt the local electronic supply house will have that die block, so I might modify that one if possible. Will
Re: Testing a 74S240
> On 04/30/2022 5:25 PM Rob Jarratt via cctalk wrote: > > > > I noticed that the chip (original and replacement) was drawing 100-110mA > from the bench PSU, which seems a bit high. > > > > I wondered if I might need a pull up resistor on the output, but my > understanding is that this is not necessary. > > > > Is there a flaw in my testing method? Have I misunderstood something > fundamental? > > > > Regards > > > > Rob There is a TI datasheet here: https://www.ti.com/lit/ds/symlink/sn74ls244.pdf According to it, the typical current is around 100 mA and it could go as high as 150. So the current sounds fine. As for the testing method, it seems like it "should" work to me. However, I would try first tying the other half enable (pin 1) to ground / vcc and see what happens. Next I would try tying all 8 inputs hi or low. None of that should make any difference, but I've been surprised before. I would also try tying the enable inputs high. It's possible you have a mis-marked 74s241 on which pin 19 is active high. Will
Comtec model P135-20/35 Paper Tape Punch
A month or two ago, someone mentioned this paper tape punch available from Surplus Sales of Nebraska. https://www.surplussales.com//Equipment/mil.html I think someone had a similar model and was looking for information. I ordered one on Tuesday or Wednesday and got it today. It came with the complete operation and maintenance manual as opposed to the three or so scanned pages they have on the website. I will be scanning that manual and making it available as soon as possible. In the mean time, if anyone has questions that the manual may have answers to, let me know. Will
Re: TRS-80 Question
> On 04/12/2022 2:11 PM Yeechang Lee via cctech wrote: > > > Eric Dittman says: > > There's a 2K hole in the Model I memory map above the ROM > Is this the hole that causes stock Model I to not run CP/M? > The ROM at address 0 is the bigger issue. CP/M requires RAM starting at address 0.
Re: Retro networking / WAN communities
> On 04/12/2022 12:42 PM Wayne S via cctech wrote: > > > Thanks for the info about IMP. > But now i’d have to question IMP routers being around in 1970 since the > internet wasn’t around yet. > > The first response of "Interface" Message Processor is more correct. There was a LOT of networking before what we call the "Internet" now. It derived from the Arpanet in the 60s, which is where the IMPs were used. https://en.wikipedia.org/wiki/ARPANET#:~:text=The%20Advanced%20Research%20Projects%20Agency,technical%20foundation%20of%20the%20Internet. Will
Re: Possibly going up to VCF, stuff I would like to sell/get to proper people pdp8/12/HP stuff
2020: oops Here: https://tcf-nj.org/wp-content/uploads/2022/03/TCF2022-SCHEDULE-TALK-INFO-PIXs.pdf > On 04/11/2022 8:48 AM Will Cooke via cctech wrote: > > > > On 04/11/2022 7:43 AM Chris Zach via cctech wrote: > > > > > > On 4/10/2022 6:05 PM, Ethan Dicks wrote: > > > Totally unrelated event. > > Ok. Does TCF still happen? > > > > > > It appears so: > https://tcf-nj.org/program/ > About 3 weeks ago. > > Will "I was born not knowing and have had only a little time to change that here and there." Richard Feynman
Re: Possibly going up to VCF, stuff I would like to sell/get to proper people pdp8/12/HP stuff
> On 04/11/2022 7:43 AM Chris Zach via cctech wrote: > > > On 4/10/2022 6:05 PM, Ethan Dicks wrote: > > Totally unrelated event. > Ok. Does TCF still happen? > > > It appears so: https://tcf-nj.org/program/ About 3 weeks ago. Will
Re: RCA COSMAC MS2000 MicroDisk Development System
> On 04/07/2022 2:50 PM Joshua Rice via cctalk wrote: > > > Hi all, > > I’ve recently come across something i’ve soon realised really quite unusual. > An RCA MS2000 MicroDisk Development System. > > I’m very green to the COSMAC scene, with this being my first 1802 machine. > I’m very interested in knowing the pitfalls i may come across in restoring > such a machine. I’ve had a quick cursory look over the machine, and it seems > to be complete, with 2 RAM/ROM cards, CPU card, FDC and a (3rd party?) ROM > programmer board, along with the PSU and floppy disk drives. > > It’s my understanding that these are pretty similar to the RCA Microboard > development systems, which i believe are also pretty similar to the ELF > “homebrew” microcomputer this group revolves around. I’ve found some manuals > on bitsavers,, a website on the Microboard system, along with disk images on > the Emma02 emulator website, so I have a reasonable undertanding over what > this actually is. > > I have a week off work next week, so am planning on taking my time on > disassembling and checking the unit over next week. > > I’ll endevour to upload some pictures of said machine when i tear it apart. > > Thanks, > > Josh Rice I recommend asking about it on the forum at http://cosmacelf.com/ Will
Re: Core memory
> On 04/03/2022 8:34 AM Magnus Ringman via cctech wrote: > > > On Fri, Apr 1, 2022 at 10:26 PM Marc Howard via cctech < > cct...@classiccmp.org> wrote: > > > We need to onshore Nixie production now! ;-) > > Gentle plug for https://www.daliborfarny.com/. I got excited by that until I saw there was no pricing and no availability. :-( Will
Re: Commodore vic 20 poweroff
> On 03/16/2022 2:58 PM Fred Cisin via cctech wrote: > > > > On Wed, 16 Mar 2022, Diedrich, Bryce via cctech wrote: > > > Just got a Commodore Vic-20. What is the safest way to power it off when I > > > am done using it? > On Wed, 16 Mar 2022, geneb via cctech wrote: > > Turn it off. > Then disconnect the power cord from the wall. > Clean the machine > Place it in a sealed container with vaccum or inert gas > > Optional: (if you are "done using it") > Post it on eBay as "R@RE" > or > place in a vault > or > drop it off at the recycling center But if you aren't completely done using it, you will likely turn it on again which is a more dangerous activity. VIC power supplies have a reputation of dying and taking the computer out with them. Many people have replaced the power supply on their VIC. The Denial wiki and forum: http://sleepingelephant.com/denial/wiki/index.php/VIC-20 is a good source of power supply options. You can also see what I did: http://wrcooke.net/classiccomputer/vicpower/vicpower.html If you really ARE done using it, you can mail it to me :-) Will
Re: HP 9915A failed 8048
> On 02/25/2022 2:23 PM Paul Berger via cctalk wrote: > > > The 8048 is a mask programmed part, there is an EPROM version 8748. > While the 8048 is mask programmed I believe that the contents of the ROM > can be dumped. > > As Paul said, the 8048 is mask programmed. However, I agree it is readable. I "think" if you follow the "verify" step in the linked datasheet you can read from the rom. https://www.ceibo.com/eng/datasheets/Intel-8048-8049-8050-plcc-dip.pdf Will
Re: OT: Who? What? Was: Re: Origin of "partition" in storage devices
> On 02/01/2022 4:08 PM Chuck Guzis via cctalk wrote: > > > > Good grief, it took DEC all that time? CDC was doing it in the 1960s. > Had to, because of the wide variety of RMS available. I think that > one of the early 2311 clone drives (854?) used 256-byte (8 bit byte) > hard-sectored media, which isn't very friendly to systems with 60 bit > words. I recall that several sectors were used to create a logical > 60-bit word addressable sector, with a substantial part of the last > sector of a logical PRU left unused. > > --Chuck LTA predates that considerably and is the earliest I am aware of. LTA (Logical Tooth Addressing) was created in the 1850's by Babbage to avoid the "shaft, gear, tooth" addressing he had been using in his "store." The teeth of all gears were numbered sequentially (starting at 0 of course) across all the gears and shafts. He even kept a few spare gears in a drawer for wear leveling. It's believed the idea actually originated with Ada since it made her task much easier. Will
Re: Origin of "partition" in storage devices
Partitioning on micros goes back to at least 1979 with CP/M 2.2. See the CP/M 2.2 alteration guide on bitsavers: http://bitsavers.trailing-edge.com/pdf/digitalResearch/cpm/2.2/CPM_2.2_Alteration_Guide_1979.pdf Will
Datum Front Panels
Some years ago I was on a mission to rack mount all my computer and test equipment. I found three front panels at a hamfest that I planned to use. I never did anything with them but still have them. These are from Datum systems, but they appear to be rather hard to find much information on. The short story is, if anyone needs them for something, let me know. I would hate to do away with them if someone needs them. Two of the panels are marked: Datum, inc Rotating Drum Memory 6008 Datum, inc Data Acquisition System 120 The last isn't marked. A picture is here: http://wrcooke.net/FrontPanels.jpg I will likely be moving in a few months and these are on the "get rid of" list. Thanks, Will
