test-drb

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101090 discussions

by gerardcjat＠free.fr

HI, I would take the bet that this IC is simply a R network, 1 KOhm, 1 resistor "across" ie from pin 1 to opposite pin, from pin 2 to opposite pin, etc .... What about simple and quick Ohmmeter check ?? --- L'absence de virus dans ce courrier ?lectronique a ?t? v?rifi?e par le logiciel antivirus Avast. https://www.avast.com/antivirus

10 years, 2 months

Making a serial board for Briel Altair Micro

by dave＠661.org

After fiddling around with my Briel Altair Micro, I've come to desire more than just the console serial port. To that end, I read up on the 16550A UART, line drivers, line receivers, and schematics for other implementations of serial ports. I came up with this: http://661.org/tmp/altairmicro-serial.pdf How close am I to this design making sense and working? -- David Griffith dave at 661.org A: Because it fouls the order in which people normally read text. Q: Why is top-posting such a bad thing? A: Top-posting. Q: What is the most annoying thing in e-mail?

10 years, 2 months

PDP 11/05 S vs 11/05 NC

by billdegnan＠gmail.com

Just to change the subject.. There were "S" and an "NC" version of 11/05 high profile system. Why? I am curious if any DEC historians here know the reason for two versions of the same DEC PDP 11/05 *high profile* computer (not talking about the low profile). There are separate manuals for each type. The S seems to be more OEM-ish because it comes in an BA11-K chassis. I am guessing you'd see an 11/05 S as part of a larger system (PDP 10), whereas the NC model would be for a stand alone system. ??? This S's BA11-K chassis was used by other hardware by simply changing the backplane. The "NC" model chassis seems to be specifically for the 11/05 I don't think it appears anywhere else. If anyone is interested to see the different models I have a thread on my site for each type: 11/05 S http://vintagecomputer.net/browse_thread.cfm?id=622 11/05 NC http://vintagecomputer.net/browse_thread.cfm?id=249 ... and then there are the 11/10's.... -- Bill

10 years, 2 months

What did computers without screens do?

by kspt.tor＠gmail.com

On 15 December 2015 at 01:31, Mike <tulsamike3434 at gmail.com> wrote: > > On 12/14/2015 08:21 PM, Chuck Guzis wrote: >> Personally, I think the world is GUI-addicted. >> >> --Chuck >> > Chuck If I may ask... > > > What would you do with a home no screen computer? I mean what could be > done with one that would benefit your work / hobby. I mean NO DISREPECT > by asking this question. I'll jump in here - take the current microcontroller hobby segment. You have PIC, or AVR, or Propeller based setups which is used for all kind of things like programmed robots, model cars, drones and RC planes, home control, model trains, temperature- and humidity controlled garden greenhouses, chicken shed day/night door control, and numerous other uses. These things are computers, a Propeller, for example, is an 8-core 32-bit small computer all in one chip. Usually these things have no screen and no keyboard connected. So you program them by various other means, e.g. through a serial interface. For the programming part of it (or the preparation of what you load via the serial interface, or jtag or e.g. a flash or eeprom chip) you'll need something else, today that's usually a PC, but that's conceptually the same thing as in times past where you used a terminal or some device with a keyboard to prepare punched cards or paper tape.

10 years, 2 months

PDP 11/05 S vs 11/05 NC

by jnc＠mercury.lcs.mit.edu

> From: William Degnan > *why* did they make these two versions of the high-profile 11/05? > What was one used for vs. the other? *Why did DEC do this*? Check the dates on the machines. I'm pretty sure the -NC is the earlier version, with the bespoke H750 power supply (mounted alongside the boards, not at the end of the box as with the BA11-K, the basis for the -S). My guess as to why they upgraded from the -NC to the -S is that the latter used the H765 (plus 'bricks') power supply system, in common with the BA11-K and also the later PDP-11's (40's, 45's, etc). That probably provided a raft of advantages, including i) greater flexibility in the current and voltages being supplied, and ii) commonality with DEC's other machines (i.e. lower unit cost -> great per machine profit margin). The BA11-K based -S also (by being a couple of inches longer, and mounting the power supply off the back) had a couple of inches more width for boards, enough to hold an extra quad system unit. And the H765 may have been technically superior to the H750, too. Noel

10 years, 2 months

Identifying Data General (or DG-related) console/terminal/whatsit?

by grif615＠mindspring.com

"Data General Alumni" ?lots of knowledge there. -------- Original message -------- From: Bruce Ray <Bruce at Wild-Hare.com> Date: 12/13/2015 7:09 PM (GMT-08:00) To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> Subject: Re: Identifying Data General (or DG-related) console/terminal/whatsit? Not identifiable as DG product - 3rd-party custom (graphics?) console for client?? (I can't read logo on bottom of console.) NOAA/NWS AFOS system had similar-looking system with interesting trackball/keyboard combination.? Then there was GE Medical... Bruce Wild Hare Computer Systems, Inc. bkr at WildHareComputers.com On 12/13/2015 5:22 PM, Josh Dersch wrote: > Hi all -- > > A friend of mine is investigating picking up some DG hardware, and this > item: > > http://yahozna.dyndns.org/scratch/dg/dg%20console.jpg > > Is included along with the rest of it.? I *know* I've seen something > like this somewhere but I can't find anything now that I need it :). Can > anyone identify this? > > Thanks, > - Josh

10 years, 2 months

CBM 1541 drive faults

by jules.richardson99＠gmail.com

I have four 1541's now, two of which seem to init OK, and two of which sit there with the drive spindle constantly spinning and the access LEDs lit, the latter behavior which I believe indicates a multitude of possible microcontroller-related faults... I've done the obvious, reseating socketed ICs, checking the +12V and +5 rails, and checking the on-board CPU reset line. Does anyone have any tips for what's best to try next? I read somewhere that ROM faults aren't unheard of, ditto with 6522 VIA failures. Also the 74ls14 at UA1 (particularly if someone's unplugged the drive from the host with power on), but I think that affects CPU reset, which appears to be working in my units. (is the firmware interchangeable between different board revisions? i.e. can I swap in firmware from one of the drives that appear to init OK to rule that out as a fault, or do I have to worry about matching PCB revisions?) Also, has there been a worse external drive in the history of floppy storage? Slow, complicated, expensive and unreliable seems to have most bases covered ;-) cheers Jules

10 years, 2 months

What did computers without screens do?

by blstuart＠bellsouth.net

On Mon, 12/14/15, Ethan Dicks <ethan.dicks at gmail.com> wrote: > On Mon, Dec 14, 2015 at 2:05 PM, Mike <tulsamike3434 at gmail.com> wrote: >> On Dec 14, 2015, at 12:34 PM, Chuck Guzis <cclist at sydex.com> wrote: >>> >>> The subject brought up the thought of how many display-less >>> computers we encounter every day without giving it a >>> thought.? I think that probably 100 would be a safe bet. >> >> .... if you think about it almost everything we touch has some kind of a >> computer cycle! ! ! GREAT POINT!!! > > Even lighting... I've pulled (and reused!) 8-pin PIC microcontrollers > out of discarded emergency lighting.? ... Along those lines, as I was preparing for a class I taught this quarter called Computing in the Small, I came across some interesting stats. Microchip crossed the 12 billion PICs shipped a few years ago and were running at nearly a billion a year then. ARM holdings quotes over 50 billion ARMs shipped. They estimate that about 60% of the Earth's population has daily contact with a device containing an ARM. That's not too far behind the 64% who have running water. And not all that long ago the 8051 was the most fabbed ISA in the world. The bottom line is that computers involving humans interacting through keyboards, mice, and screens are really just a niche in the computing world. Embedded systems are the predominant class of computing systems. Or to twist a line from Shakespeare, There's more in the universe of computing than is dreamt of in the PC philosophy. BLS

10 years, 2 months

Webster WQSMD/04 Qbus SMD Controller

by robert.jarratt＠ntlworld.com

I picked up some Qbus cards yesterday. They seem to be board set for a MicroVAX II. However, one of the cards was, to me at least, a bit unusual. It was made by a company called Webster, and it appears to be a controller for SMD disks. I was not familiar with SMD disks and had to look them up. I suspect this might be a little out of the ordinary, and, possibly, an odd combination for a small Qbus system to access such a physically large type of disk. Were MicroVAX IIs used much with such disks? Is this a bit of an unusual find? Regards Rob

10 years, 2 months

New Heathkit videos...

by geneb＠deltasoft.com

Part 2: Backplane Circuit Board: https://www.youtube.com/watch?v=YdeHfcasBbM Part 3: RAM Board: https://www.youtube.com/watch?v=fwbO4bBnpEg g.

10 years, 2 months

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