Re: Care and feeding of true barn-find systems
On 4/19/19 2:44 PM, Chuck Guzis via cctalk wrote: When he opened it, he discovered a nest of brown recluse spiders, one of which bit him. Sidelined him for awhile. I prefer starting projects like that very early in the year. When most critters will not have survived hard / prolonged freezes during the winter. Or at least open them up and get obvious unpleasant things like that out of the way. Then wait until the weather warms up. }:-) -- Grant. . . . unix || die
Re: Care and feeding of true barn-find systems
On 4/19/19 12:46 PM, Alan Perry via cctalk wrote: > > Yesterday I rescued a Sun 3/260 that had been sitting in an open barn > for years. It had been "running when parked" a dozen years ago. It > seems to have been covered by a tarp, but otherwise unprotected. All > things considered, it doesn't look that bad but it is pretty rough. > > Any pointers on things that I should and shouldn't do as I start trying > to bring it back to life? Disassemble it outside preferable while wearing globes and let the vermin escape. No kidding.quite a few years ago, I was chatting with a poor fellow who was rehabilitating a bit of kit that was stored in his garage loft. When he opened it, he discovered a nest of brown recluse spiders, one of which bit him. Sidelined him for awhile. --Chuck
MSCP Conformance tests?
I'm working on implementing an MSCP controller on top of Joerg Hoppe's Unibone and I'm making pretty good progress -- RT-11 works and I'm working on getting 2.11bsd to boot from it in an 11/84 (it works well enough to load "boot" which then loads the kernel, then things fall over). However, given the complexity of the protocol I'd like to be able to test it against something official rather than going from OS to OS and hammering out issues as I find them. DEC's UDA50 diagnostics assume an actual UDA50 (and expect specific behaviors like onboard diagnostics, etc.) and I don't really want to emulate a UDA50 -- I just want to implement a generic MSCP controller properly. I'm assuming the answer is "no" but did DEC ever provide actual MSCP conformance tests (for PDP-11 or VAX) to allow third parties to test their implementations? Thanks as always, Josh
Re: Care and feeding of true barn-find systems
On 4/19/19 12:46 PM, Alan Perry via cctalk wrote: > Any pointers on things that I should and shouldn't do as I start trying to > bring it back to life? Pull the Fuji power supply and thoroughly bench-test it. There is a high probability it will have failed.
Re: Care and feeding of true barn-find systems
complete disassembly, don't be afraid to use soap and water (dry well) before you start with the chemical cleaning agents. Replace the battery, check for battery leakage.(but I doubt you'll find any). The rubber parts and drive belt if present may need to replaced. Bill On Fri, Apr 19, 2019 at 3:46 PM Alan Perry via cctalk wrote: > > Yesterday I rescued a Sun 3/260 that had been sitting in an open barn > for years. It had been "running when parked" a dozen years ago. It > seems to have been covered by a tarp, but otherwise unprotected. All > things considered, it doesn't look that bad but it is pretty rough. > > Any pointers on things that I should and shouldn't do as I start trying > to bring it back to life? > > alan > >
Care and feeding of true barn-find systems
Yesterday I rescued a Sun 3/260 that had been sitting in an open barn for years. It had been "running when parked" a dozen years ago. It seems to have been covered by a tarp, but otherwise unprotected. All things considered, it doesn't look that bad but it is pretty rough. Any pointers on things that I should and shouldn't do as I start trying to bring it back to life? alan
Re: Plane of core memory
I'll be curious to hear what you end up getting. I've also meant to acquire one over the years just for historical education and display sake. One thing to keep in mind, but I'm sure you're aware is the physical size. Often they're quite small. However I think eBay sellers recent years have been better about letting you know that expectation. I've also seen the large amount of Russian planes. Not too bad although like you said, I'm not sure you'd find out what system they came out of but you could always ask the seller prior to bidding. I find those and silicon wafers in a similar light of something pretty to look at. As well as an educational glimpse into explaining some history. Good luck! Sent from my Apple /c > On Apr 17, 2019, at 11:30 PM, Andrew Luke Nesbit via cctalk > wrote: > I have been wanting to acquire a plane of magnetic core memory as a > piece of computing history. My partner actually thinks they look very > beautiful and says we should frame it, if we ever find a plane.
Re: that AGC DSKY auction
didnt notice that only went for 242 On Fri, Apr 19, 2019 at 1:34 AM Jim Manley via cctalk wrote: > Bidding hasn't ended on the display electronics, but, it's not clear when > bidding will end, so, bid high and often! :D > > On Thu, Apr 18, 2019 at 8:05 PM Adrian Stoness via cctalk < > cctalk@classiccmp.org> wrote: > > > weird this only went for 220 bucks > > https://www.rrauction.com/bidtracker_detail.cfm?IN=5109 > > >
Re: Plane of core memory
> On Apr 18, 2019, at 11:18 PM, dwight via cctalk wrote: > > Although, after written, there is little magnetism lost out side of the ring, > while being magnetized, there is quite a bit of stray magnetism. By placing > the the rings at 90 degrees, it minimizes the magnetism induced in the > adjacent ring. The fields follow the inverse square law so the effect drops > off quite quickly. Also the ring tend to pull the magnetic field into the > ring, at least until saturated. At that time the field can leak into a > neighbor and flip its state. Not being aligned with the direction of the ring > also minimizes this stray field. > Dwight … inverse cube (?) … depending on the geometry you are talking about? Real physicists please set me right if I have this wrong, but I think only radiating and static point fields (like electric or gravitational) from a finite source fall off as inverse square. That’s easy to see, it’s the same effect crossing the total area of a sphere centered at the source. Area on the sphere goes up like square of radius, so intensity has to go down like the square. Magnetic field (from a finite source) I think goes down like the cube of the distance - north and south poles of the source tend to cancel better as the apparent angle between them gets smaller, in addition to the above effect. (That is a mnemonic, not a real explanation.) On the other hand, if you were talking about field around a wire with current in it (a non-finite source, at least locally), then it *is* inverse square for the magnetic field, where inverse square refers to distance from the axis of the wire. - Mark
Re: Plane of core memory
> On Apr 18, 2019, at 9:01 PM, Anders Nelson wrote: > > I believe I read they weaved the planes this way to minimize crosstalk, EMI > or heat. > > =] The zigzag routing, you mean? Yes, that's to minimize crosstalk. It's nicely described in a training manual for the Electrologica X1. The issue is that concident current selection send a "half-current" pulse through a whole row and column of cores. While the resulting induced current in the sense lines is small per core, it isn't zero since the hysteresis curve isn't perfectly square. If all those pulses summed up, the resulting noise would swamp the signal from the selected core. The solution is to route the sense line so it passes through the cores in a zig-zag fashion. This means half the cores in a row or column generate a pulse of one polarity while the other half produce the opposite polarity. If all cores were identical you'd end up with just two cores worth of noise. They aren't all identical, of course, but it still reduces the noise enough to avoid the problem. A similar but not identical issue appears in rope core ROM. Brent Hilpert's paper on those devices shows how it was solved there (in the AGC flavor; the ELX1 does it differently). paul
Re: Plane of core memory
> From: Curious Marc > I believe 3 wire memory was first introduced by IBM in their 360 > systems ... They would almost certainly have patented their way to do it Correct (and your knowledge and memory is good)! Motivated by this clue, I looked in: Emerson W. Pugh, "Memories That Shaped an Industry" MIT Press, Cambridge, 1984 where the description of the invention of 3-wire core can be found on pg. 231; it was invented by a group of engineers, based on a similar idea used in Stretch. There is indeed a patent, No. 3,381,282, with six names on it. IBM must have licensed it, but there is nothing on that. I can highly recommend that book; it's in the same league as the later two books on early IBM computers from MIT Press on which he was a co-author. Noel PS: There was recent discussion here of the 8000 series; there are some details on that on pp. 189-191.
Latest additions to Sellam's sale list
Happy Spring, fellers! Here is the latest batch of goodies for your perusing pleasure: Amiga 3000-25/50 Commodore 1902A Monitor Daystar Digital Turbo 601 Accelerator Radius Precision Color Pro 24XK Accelerated 24-bit Graphics I/F Atari Mega ST4 Atari Mega ST Keyboard (American) HP Plotter Pens 0.3mm - 5 pen BLACK Pack (Paper) HP Plotter Pens 0.3mm - 5 pen BLUE Pack (Paper) HP Plotter Pens 0.3mm - 5 pen PURPLE Pack (Paper) HP Plotter Pens 0.3mm - 5 pen ORANGE Pack (Paper) HP Plotter Pens 0.3mm - 5 pen RED Pack (Paper) HP Plotter Pens 0.3mm - Multi-Color Custom Pack (Paper) HP Plotter Pens 0.6mm - 5 pen GREEN Pack (Transparency) HP Plotter Pens 0.6mm - 5 pen BLUE Pack (Transparency) HP Plotter Pens 0.6mm - 5 pen RED Pack (Transparency) HP Plotter Pens 0.6mm - 5 pen PURPLE Pack (Transparency) HP Plotter Pens 0.6mm - 5 pen Multi-Color Pack (Transparency) HP Plotter Pens 0.7mm - 5 pen BLACK Pack (Paper) HP Plotter Pens 0.7mm - 5 pen GREEN Pack (Paper) HP Plotter Pens 0.7mm - 5 pen BLUE Pack (Paper) HP Plotter Pens 0.7mm - 5 pen PURPLE Pack (Paper) HP Plotter Pens 0.7mm - 5 pen RED Pack (Paper) IBM PCjr with IBM PCjr Carrying Case IBM Terminal Controller Port Box IBM PS/1 Consultant Atari 520ST Atari Portfolio Technical Reference Guide HP 9815 Hayes Smartmodem 1200 Hayes Smartmodem 2400 Hayes Smartmodem OPTIMA 2400 Iomega PC800B SCSI Controller Star Micronics NX-1000 Multi-font Printer Disk interface bus monitor Electrohome TTL Color Interface Navarone Commodore 64 carthridge port expander Practical Peripherals Pocket FAX/Modem Apple StyleWriter II Sun Microsystems SPARCstation 1 Sun Microsystems SPARCstation Prototype Links to information on these items and more can be found here: https://docs.google.com/spreadsheets/d/1I53wxarLHlNmlPVf_HJ5oMKuab4zrApI_hiX0pNmy48/edit?pli=1#gid=949372371=A1 Photos on the latest posted items will be available later this evening. You may always inquire if you require more information on a particular item. Per standard procedure, please contact me directly via e-mail to make an offer on a particular item. Thanks! Sellam
Re: Plane of core memory
I believe 3 wire memory was first introduced by IBM in their 360 systems, and it was a very large development effort. They would almost certainly have patented their way to do it, but I have not checked. Marc From: cctalk on behalf of "cctalk@classiccmp.org" Reply-To: Jon Elson , "cctalk@classiccmp.org" Date: Thursday, April 18, 2019 at 7:08 PM To: Noel Chiappa , , "cctalk@classiccmp.org" Subject: Re: Plane of core memory On 04/18/2019 03:15 PM, Noel Chiappa via cctalk wrote: > From: Jon Elson > As soon as somebody figured out that you could combine the sense and > inhibit wires, everybody immediately went to 3-wire planes. I"m suprised the idea wasn't patented. Or maybe it was, and they made the license widely available at modest terms? I was thinking the same thing, but can't find any references to who invented it. it certainly sounds like the sort of thing to get a patent on. Point of interest, my freshman advisor was Bill Papian, who was Jay W. Forrester's grad student when he invented coincident-current core memory. Jon
Re: that AGC DSKY auction
Bidding hasn't ended on the display electronics, but, it's not clear when bidding will end, so, bid high and often! :D On Thu, Apr 18, 2019 at 8:05 PM Adrian Stoness via cctalk < cctalk@classiccmp.org> wrote: > weird this only went for 220 bucks > https://www.rrauction.com/bidtracker_detail.cfm?IN=5109 >
