- test-drb@ccmp.vtda.org - classiccmp.org

by ethan_dicks＠yahoo.com

--- Cameron Kaiser <ckaiser(a)oa.ptloma.edu> wrote: > [C= 1520 plotter] > ::Does anyone out there have any software for it? (I don't recall seeing > ::any on ftp.funet.fi). > > As a matter of fact, *I* do. Do you get comp.binaries.cbm? Yes, but I don't check it as frequently as I used to (not your fault... I don't have telnet access to my primary news server from where I am). -ethan _________________________________________________________ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com

27 years, 2 months

2
1
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What if,... early PCs (was: stepping machanism

by edick＠idcomm.com

It would be well to get the timelines aligned. The model 1 was of 1977 vintage. The model -3 was worked up in the late '70's before Apple got its juggernaut rolling. Radio Shack had a real chance to make the microcomputer market its own. No one had a decent sales and service network, not to suggest that Radio Shack's was really decent, but at least it was there. The Model 3 was out in '81? by which time double density was "old hat" and by 1982-1983, Apple had the door closed. Having turned out two (if not more) pieces of relative rubbish, the RS people had no chance after 1983. IBM was gaining acceptance (nobody ever got fired for buying IBM, right?) and ultimately legitimized the PC for "respectable" business use. By mid '84, the 8-bitters were in the "Komputerdaemmerung." Dick -----Original Message----- From: Allison J Parent <allisonp(a)world.std.com> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Friday, April 09, 1999 5:09 PM Subject: Re: What if,... early PCs (was: stepping machanism ><The RCA TV set design that RS used for a monitor for the model 1 was NOT ><really adequate for 80x24 display. (YES, I've done it.) > >It could but the opto isolator used to keep the hot chassis and the video >seperate wasn't up to the task. Bypassed and of course using an isolation >transformer it was much crisper even at 80 cols. > ><Double density was NOT readily achievable in 1978. And the poor quality > >My dog, don't tell DEC that or intel. > ><> was SLOW. The Z-80-card in the Apple was significantly (and noticeably) ><> faster. The two machines otherwise occupied about the same desk space, a > >Than the TRS80, every thing was faster. Next to my S100 CPM crate with a >real 4mhz z80 and no wait state memory they were both slow. > ><> aside from the stupid, Stupid, STUPID choice to leave the Tandy machine' ><> display at 16 lines of 64 characters (about half of what was on a 24x80, > >As it works 64wide was more useful for word processing than 32 or 40. > >Allison >

27 years, 2 months

8
13
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**** RARE ***** ISA card

by Philip.Belben＠pgen.com

>> The one Mike has is definately the proprietary one (I also have one sitting >> here). It was packed with scanners like the ScanJet Plus. > > If that one is rare then the MCA version I use with the scanjet I have > must be unique! ;) On the contrary, I have a scanjet (which I've never used) and the MCA adapter. I have no machines with MCA, though (yet!), so I might be offering to buy the ISA version. One day... Philip.

27 years, 2 months

1
0
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Centronics printer ribbons...

by jimw＠agora.rdrop.com

NOS! RARE!! VALUABLE!!! (yeah, right...) In the boxes from a recent acqusition, I found a number of boxed of Centronics 'Linewriter' 400/800 and 1200 series ribbon cartridges. Since I don't have any of these printers in the collection (in fact, have never heard of the thing!), they are available to anyone who can use them for cost of shipping or flat out free if you pick them up! There are about six boxes (of six carts each) of the 400/800 ribbons, and one box of the 1200 ribbons. Of course, if you want to offer something interesting in trade, thats cool as well! B^} -jim --- jimw(a)computergarage.org The Computer Garage - http://www.computergarage.org Computer Garage Fax - (503) 646-0174 >>> Coming soon to www.computergarage.org - the CBBS/NW on-line archives >>> Coming to VCF III (2-3 October 1999) - CBBS/NW live!

27 years, 2 months

3
2
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Powerlines

by Philip.Belben＠pgen.com

[Power supplies with earth return] > I have never looked but I suppose it might. I have a 400A service and > sometimes I do a fair job of loading it. The transformer ped is out of the Another difference! It is very unusual in the UK to give a domestic customer more than 100A in the main incoming fuse. 400A on each side of your 115-0-115 supply is getting on for 100kW. Do you really use that? I would have thought 10kW would be more likely (my parents use 36kW at the winter peak, mostly heating load. 50A from each of three phases at 240V) Anyway, 400A on the 240V side corresponds to nearly 7A to be returned through the earth at 14kV. Ouch! I wonder what the resistance of the earth connection is. There will be a minimum resistance to prevent undue voltage rise under short circuit conditions, but I don't know how this relates to earth return circuits... The only places where I've seen this sort of arrangement, there are still 2 conductors. One insulated to HV for the line, and one lightly insulated for the (HV) neutral. > way so I rarely go closer than 30 feet from it. They also must put the > ground rod(s) inside the for safety (hate to think what it would be like if ISTR that in the UK there is a minimum distance between LV and HV earth electrodes. > the ground got cut on the primary). I have never seen them but they have to > be there somewhere. Earth open circuit? Hmm. The entire HV winding rises to 13kV and the HV neutral flashes over to the transformer tank? Assuming the tank is part of the LV earth system. Otherwise the transformer tank rises too, and flashes over to your house supply... Philip.

27 years, 2 months

1
0
0 0

Linux tempts back Sinclair

by dwollmann＠ibmhelp.com

Looks like Clive Sinclair is working on another portable, this time with Linux and a non-Intel CPU. http://webserv.vnunet.com/www_user/plsql/pkg_vnu_template.comp_news?p_to_da… -- David Wollmann DST / DST Data Conversion http://www.ibmhelp.com/

27 years, 2 months

1
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How scarce (valuable) is core for the PDP-8?

by Philip.Belben＠pgen.com

><OK, how about it. Put a ring of compasses around the wire with needles str ><enough magnetised that they will stay pointing N-S around the ring regardle ><the Earth's field. >< ><Can you then flip them with a current? A very good visual demonstration of ><core works! > > Yep, That would be good to watch but that's really a demo of the fields > around conductors (imporant building block). I actually meant to take the demo one step further. Each compass needle has its own magnetic field. Put them close enough together and (with luck) the N end of one needle will attract the S end of the other. Put several of these compases in a ring, and the needles will point around the ring, whether or not there is a current flowing down a wire in the middle. And there are two stable states, just like a core. With (even more) luck, you can flip between states with a current. Just like core. Worth a try? This weekend I shall see if I can find some cheap, small compasses in a toy shop or somewhere... Philip.

27 years, 2 months

2
1
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Computer history

by foxvideo＠wincom.net

If interested, check out Mary Bellis' "History of Modern Computers and their Inventors" at http://inventors miningco.com/library/blcoindex.htm Regards Charlie Fox Charles E. Fox Chas E. Fox Video Productions 793 Argyle Rd. Windsor N8Y 3J8 Ont. Canada email foxvideo(a)wincom.net Homepage http://www.wincom.net/foxvideo

27 years, 2 months

1
0
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rt-11 (ht-11) help

by cmcmanis＠mcmanis.com

Ok, I booted a disk labelled "HT-11B distribution" on my H-11 and it comes up to the "." prompt. But not much else. (dir doesn't work for example) Is there a clue page somewhere ? --Chuck

27 years, 2 months

5
4
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rt-11 (ht-11) help

by CLASSICCMP＠trailing-edge.com

>had DCL incorporated in it... to get a directory, you have to >run PIP (R PIP) and issue the command 'ddx:/L' where dd is the >device you're using (presumably DX) and 'x' is the unit number. Yep, ignore my comment about R DIR. I'm pretty sure that DIR.SAV didn't exist until CCL came about (though of course you never know for sure with HT-11...) I spent an hour explaining to the folks at Mentec yesterday how IGETC and IFREEC aren't in RT-11 V5.5 and later SYSLIB.OBJ, despite how the manual said that they were still there :-). -- Tim Shoppa Email: shoppa(a)trailing-edge.com Trailing Edge Technology WWW: http://www.trailing-edge.com/ 7328 Bradley Blvd Voice: 301-767-5917 Bethesda, MD, USA 20817 Fax: 301-767-5927

27 years, 2 months

1
0
0 0

rt-11 (ht-11) help

by mbg＠world.std.com

>Ok, I booted a disk labelled "HT-11B distribution" on my H-11 and it >comes up to the "." prompt. But not much else. (dir doesn't work for example) I believe HT-11 was based on a version of RT-11 which had not yet had DCL incorporated in it... to get a directory, you have to run PIP (R PIP) and issue the command 'ddx:/L' where dd is the device you're using (presumably DX) and 'x' is the unit number. Megan Gentry Former RT-11 Developer +--------------------------------+-------------------------------------+ | Megan Gentry, EMT/B, PP-ASEL | Internet (work): gentry!zk3.dec.com | | Unix Support Engineering Group | (home): mbg!world.std.com | | Compaq Computer Corporation | addresses need '@' in place of '!' | | 110 Spitbrook Rd. ZK03-2/T43 | URL: http://world.std.com/~mbg/ | | Nashua, NH 03062 | "pdp-11 programmer - some assembler | | (603) 884 1055 | required." - mbg | +--------------------------------+-------------------------------------+

27 years, 2 months

1
0
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rt-11 (ht-11) help

by CLASSICCMP＠trailing-edge.com

>Ok, I booted a disk labelled "HT-11B distribution" on my H-11 and it comes >up to the "." prompt. But not much else. (dir doesn't work for example) Try a "R DIR". What is the exact text of the error message? (You know, the error messages are not put there for you to ignore. They do mean something to others, even if they seem cryptic to you.) >Is there a clue page somewhere ? I think your copy of HT-11B will be roughly equivalent to RT-11 V2 (maybe V3). No online help. You should find the big set of blue books that came with it! Many of the utility options from later versions of RT will work, but not all, and the details of a SYSGEN changed greatly between major versions. -- Tim Shoppa Email: shoppa(a)trailing-edge.com Trailing Edge Technology WWW: http://www.trailing-edge.com/ 7328 Bradley Blvd Voice: 301-767-5917 Bethesda, MD, USA 20817 Fax: 301-767-5927

27 years, 2 months

1
0
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Great Find !

by lwalker＠mail.interlog.com

Doing a casual dumpster dive this eve and found a box with Vic-1520 Colour Printer Plotter. NIB including manual and cables. Unopened tube containing the 4 colour nibs. Dont know if they're dried out but they're water-based. An MJB H8401 4 socket game-port expander and 40/80 converter in a really sturdy metal case with 6-led select switch and reset. C= 802 printer like new. New parallel card for Apple ll with cable and lle socket plus typed manual >from PC Wares . What looks to be a 1/2 ht. 5 1/4 Apple ll floppy in a 1541 case usual All cable but with a different non-apple controller card inside ?? A Bantam paperback manual on the Timex-Sinclair 1000 and a couple of copied mmanuals (Oxford Pascal for C64, Spinnaker), a package from Quantum Link with a discount coupon. Wonder if AOL would honor it ? :^)) Made my day ! ciao larry lwalker(a)interlog.com Let us know of your upcoming computer events for our Events Page. t3c(a)xoommail.com Collectors List and info http://members.xoom.com/T3C

27 years, 2 months

3
2
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Powerlines

by danburrows＠mindspring.com

I agree in principle but I just double checked my memory and just looked at my HT feed. It is only connected to the HT line and then drops down into a conduit and under ground for the ~800 feet to the pedistal mounted transformer. There is only the 1 connection at the pole. A friend of mine used to burry lines for the local phone company and has hit on occasion (when the locator screwed up) the 14KV drops and said all he ever finds is a single wire from the result. He did say it is impressive when it gets shorted however. He has melted teeth off the backhoe bucket and his ears hurt for a while afterwords. It also works wonders on the ditch witch teeth and the vibrating plow blades. Even though the power drops are supposed to be a minimum of 3 feet down that is not always the case. Dan > I don't know about where you come from but in my state, >the power company is required to keep the ground current to >a minumum. The smallest power line I've see was two wires. >Much of the older telegraph lines used ground return. I don't >think it would be good for general power distribution. They also >used ground return on many telephone setups. > This reminds me of a story I once heard: > A phone repairman heard of this dog that could predict >when the phone would ring. A few seconds before the bell >rang, the dog would let out a howl. > He had to see this magic dog. > He when to the old ladies house and he found the dog chained >to the telephone box on the side of the house. He then realized >how the dog knew. You see, it was winter and the ground was >frozen at the box. This meant that when a ring came in, it >didn't have enough current to make the bell ring but there >was enough current to give the dog a strong shock through >the chain. The poor dog would get a nasty shock and urinate >on the ground. On the next ring, the urine would provide >enough conduction that the bell would ring. > That is the story of the magic dog. >Dwight > >Dwight >

27 years, 2 months

4
3
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Powerlines

by danburrows＠mindspring.com

> >I've just gotta ask! Does it bring the worms to the surface when it >rains? > - don I have never looked but I suppose it might. I have a 400A service and sometimes I do a fair job of loading it. The transformer ped is out of the way so I rarely go closer than 30 feet from it. They also must put the ground rod(s) inside the for safety (hate to think what it would be like if the ground got cut on the primary). I have never seen them but they have to be there somewhere. Dan

27 years, 2 months

1
0
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Powerlines

by danburrows＠mindspring.com

>> >How can the transformer possibly work if the primary is only connected to >> one >> >HT line? What is the other side of the primary connected to? Where's the >> >return path? >> >> Earth > >I had an electronics tech that worked for me a number of years, and we were >working on some control circuits that had only one wire between two panels. >In answering the question as to how the path was completed, his answer (I >hope tongue-in-cheek) was through the air. I am assuming here that "Earth" >was also said tongue-in-cheek! > It is the actual way they do it here. See my prior post from looking at the pole feed. Dan

27 years, 2 months

1
0
0 0

When stuff has to go

by clintw＠colorado.cirrus.com

I'd kick in ten buck or so for a picture of the bonfire :) > > Especially if its not limited to 10 year old stuff. I have all these > Microsoft manuals and CD's for learning about Microsoft NT 4.0 > (mainly administration stuff)... What i'm gonna do with 8-10 sets > of this stuff is puzzing me to no end. > > -Lawrence LeMay >

27 years, 2 months

1
0
0 0

Powerlines

by danburrows＠mindspring.com

> >How can the transformer possibly work if the primary is only connected to one >HT line? What is the other side of the primary connected to? Where's the >return path? Earth

27 years, 2 months

3
2
0 0

Available: Versatec

by jlwest＠tseinc.com

In one of the HP 21MXE machines I received recently, there is a Versatec printer interface. I have no need for it at all. It consists of about 6 or 8 interface cards, plus a rackmount box. From what I can tell, it was used to hook up a versatec plotter. It also *APPEARS* to have a parallel interface on the box, but I don't know any particulars, this may not be correct. If someone has a real use for it, they're welcome to have it for shipping costs. However, if no one claims it, I will likely strip off the front panel switches on the rackmount box (which are the authentic style for my Nicolet-80 which has some non-authentic front panel switches installed by the last user) and pitch the rest. If interested, just email me for particulars. Jay West

27 years, 2 months

1
0
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Powerlines

by danburrows＠mindspring.com

>"Daniel T. Burrows" <danburrows(a)mindspring.com> wrote: >> Close but not quite right. For single phase installations the power company >> supplies 2 hots and neutral. This is a center tapped secondary and the >> neutral is earthed at the service entrance. > >No, for split-phase, the power company does not "supply" a neutral from the >distribution system. The neutral is *only* tied to the center tap of the >secondary and to ground. It is not tied to anything on the primary side of >the transformer; that would be bad. That is what I was trying to decsribe above. >> The primary of this transformer >> is fed from only 1 high voltage phase. > >I don't believe this; it doesn't match the descriptions I've read elsewhere. >I've always seen it shown in diagrams with the primary connected across two >phases of the three-phase. Otherwise you need a high-current return path >somewhere else. Take a close look at rural areas and there is only 1 High voltage line present. It is fed to the HT input of all the pole transformers. >To even the loading of the phases, the transformers for split-phase service >have their primaries distributed between the three possible combinations of >the three phases. When there are 3 phases available that sometimes is the case. Look closely at the pole transformers and in most cases when there are 2 or more transformers mounted on 1 pole there is only 1 HT input to each transformer. If it were between phases there would be 2 HT inputs. Dan

27 years, 2 months

5
4
0 0

RARE: Original Macintosh found!!

by gregorym＠cadvision.com

At 09:21 PM 4/25/99 -0700, you wrote: >At 09:43 PM 4/25/99 -0600, you wrote: >>My original post may have been misleading. It just says "Macintosh" on the >>back of the case. I'm assuming that it's a 128K Mac because: ... >> >>How can I check the memory capacity, to see if it's a 128K or a 512K Fat >>Mac? I'm not that familiar with Macs. > >Boot it up, drop down the left hand (I think) menu and select 'About >Finder'. This should indicate the memory in the system. > >-jim > >--- >jimw(a)computergarage.org >The Computer Garage - http://www.computergarage.org >Computer Garage Fax - (503) 646-0174 > When I choose "About the Finder ...", I get "The Macintosh Finder Version 1.0 (18 Jan 84) @ 1984 Apple Computer" No mention of memory size. But I would guess that it doesn't mention the memory size because no size other than 128K was contemplated; i.e. this is an original Mac. Any other way to check? BTW, were the "Programmer's switches" (Interrupt and Reset) de-emphasized after the original Mac? My Mac Plus has the same microswitches inside the case, but I had never heard of them before. This system is a bit of a puzzle. As I understand it, a single drive original Mac was almost unusable, due to lack of RAM and the need for frequent disk swaps. So I would expect mint condition. However, this system (Mac, mouse, KB, Imagewriter printer) shows some signs of wear, even though it was never upgraded to 512K, and there was no second drive with the system. Regards, Mark

27 years, 2 months

3
2
0 0

XXDP+ 2.5

by CLASSICCMP＠trailing-edge.com

>> > CKK FA <xy> 1 11/44 Diagnostic ROM* >> >My second problem is the first test, I can't find a KKFA*.* test. Is there >> >another test I can run on the diagnostic ROM? >> >> The diagnostic ROM *is* the test :-). This is the "big" bipolar >> PROM located near the boot PROM's. And the test is executed at startup. >OK, I'll buy that, BUT why was there a Diagnostic for the Diagnostic ROM at >one point? It does seem rather redundant though. I think you're taking the table too literally: the Diagnostic ROM *is* the Diagnostic ROM test :-). Generically, it's a dirt-simple memory test which also gives the CPU a bit of a exercise (simple bit manipulation and looping) in the process. At least some of the Diagnostic ROM's also do a checksum on themselves (this is actually a requirement for firmware in some European countries) but I don't know if the 11/44's ROM does this. >> >CKKKAC0 11-44 KK11B CACHE >> > >> >RMI REGISTER (G5179) NOT USED-SKIP HI ORDER BIT ADDRESS TEST >> >> The G5179 is the PDP-11/44 Remote Memory Interface (an extremely >> rare option). You don't have it :-). >Ah, good, this was the most disturbing of the messages I got. *Generally*, G-series modules referred to by XXDP+ are modules with special diagnostic purposes. These G-modules are often simulators or exercisers, and in many cases were not often found outside of the manufacturing and repair facilities. Other G-series modules are the components of low-level formatters and dedicated hardware test jigs. Many of these modules, according to the hardware indices I have at hand, were custom-wrapped boards produced in extremely small (sometimes only 1 or 2) quantities, yet they still have G-numbers. >Now I've just got to pour through the doc's for the peripherals so I can >figure out what tests to run on them. For at least your RL11 and RL02's: ZRLG?? Controller Test #1 ZRLH?? Controller Test #2 ZRLI?? Drive Test #1 ZRLJ?? Drive Test #2 ZRLK?? Performance Exerciser ZRLL?? Drive Compatiblity Test ZRLM?? Bad Sector File Utility Running the drive tests or performance exerciser with multiple drives at the same time produces an impressive light show as all the unit lights blink in both regular and random patterns! -- Tim Shoppa Email: shoppa(a)trailing-edge.com Trailing Edge Technology WWW: http://www.trailing-edge.com/ 7328 Bradley Blvd Voice: 301-767-5917 Bethesda, MD, USA 20817 Fax: 301-767-5927

27 years, 2 months

1
0
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XXDP+ 2.5

by CLASSICCMP＠trailing-edge.com

>My single biggest problem seems to be stopping a diagnostic once I've >started it. So far I've been resorting to stopping the CPU and rebooting, >but one would think that there must be a better way, and that I've missed >it. You don't have to reboot; you can often just halt the CPU and start up XXDP+ again at the restart address (this is given at boot time as a message on the console.) Some diagnostics (especially the really extensive memory diagnostics) wipe out the XXDP+ monitor and you do, indeed, have to reboot. > CKK FA <xy> 1 11/44 Diagnostic ROM* >My second problem is the first test, I can't find a KKFA*.* test. Is there >another test I can run on the diagnostic ROM? The diagnostic ROM *is* the test :-). This is the "big" bipolar PROM located near the boot PROM's. And the test is executed at startup. #3 is #3, but I think this is proper behavior CKKABD0 11/44 TRAPS NO FLOATING POINT OPTION PRESENT NO CIS OPTION PRESENT CONSOLE 17777707 023252 >>> >#5 may or may not be a problem with the cache (real problem is my not >knowing how to interpret it). > >CKKKAC0 11-44 KK11B CACHE > >RMI REGISTER (G5179) NOT USED-SKIP HI ORDER BIT ADDRESS TEST The G5179 is the PDP-11/44 Remote Memory Interface (an extremely rare option). You don't have it :-). >UNIBUS EXERCISER NOT USED-DMA TESTS NOT PERFORMED There was also an optional Unibus exerciser that could be installed instead of the normal terminator. These aren't all that rare - they're very commonly found inside 11/750's. -- Tim Shoppa Email: shoppa(a)trailing-edge.com Trailing Edge Technology WWW: http://www.trailing-edge.com/ 7328 Bradley Blvd Voice: 301-767-5917 Bethesda, MD, USA 20817 Fax: 301-767-5927

27 years, 2 months

2
1
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Powerlines

by danburrows＠mindspring.com

>> > Take a close look at rural areas and there is only 1 High voltage line >> > present. >> > It is fed to the HT input of all the pole transformers. > >Same thing is done in rural areas in Oz. They are called SWR lines, which >is TLA for Single Wire Run AFAIK. >Not sure of the voltage, but I think it's around 8kv. (240v to subscribers) >They are somewhat unpopular, and are prone to surges and sags etc. >Given the nature of the return path, (ground) and the way it would be >affected by weather etc, this is not surprising. I would think it would have a lot more surges and sags than it does. I guess they manage to keep the HT runs short enough however. I have several 1 to 3 KVA UPS's here and rarely (except during storms) do they kick in. Boy does it get noisy then with all their alarm beepers going.:) Can't wait to move them out once I make room (and get batteries for) the 10 KVA online UPS I picked up. The HT lines I am on are around 14.5KV. The typical distribution lines I have found vary from12KV to 14.5 in the different areas I have lived. Currently in North Carolina. Dan

27 years, 2 months

1
0
0 0

MVME System

by karlm＠blitzen.canberra.edu.au

Ok, I've finally dusted off this Motorola box I got the other day, it has a MVME-101 CPU Card, A MVME225-2 Memory card and a MVME 319 Controller. It runs OS/9 v2.1, it appears to have been used for some kind of robotics application, but all the other cards have been removed. Does anyone have more info on this box? Cheers Karl ------------------------------------------------------------------------------ Karl Maftoum Computer Engineering student at the University of Canberra, Australia Email: k.maftoum(a)student.canberra.edu.au

27 years, 2 months

2
1
0 0

Some things make me want to toss my cookies ...

by CLASSICCMP＠trailing-edge.com

>> http://www.bccc.com/nancy/memorydress.html > >Core memory in oscilliscopes? Where did she get that idea? She also talks about medical equipment, which causes me to believe that most of the core memory she gets comes out of pulse height analyzers >from the late 60's to the mid 70's. These look a lot like oscilliscopes to the untrained idea (they have a CRT, lots of knobs, BNC jacks, etc.) -- Tim Shoppa Email: shoppa(a)trailing-edge.com Trailing Edge Technology WWW: http://www.trailing-edge.com/ 7328 Bradley Blvd Voice: 301-767-5917 Bethesda, MD, USA 20817 Fax: 301-767-5927

27 years, 2 months

1
0
0 0

More 3rd Party DEC boards

by healyzh＠aracnet.com

Hmmm, this is really odd, I found some more boards that I don't seem to have inventoried today. Anyone have any ideas on these? Versatec PDP-11 Matrix control This is a dual height board, but I'm pretty sure it's for a UNIBUS system, thanks to the wierd connector sticking out the side of it for another board. DILOG DQ342 Quad Height, has a 34 and a 10-pin connector SCD-RQD11/EC Quad Height, 4 20-pin connectors, 1 34-pin, and 1 10-pin. 3 LED's 2 green, 1 red. I think it's a Sigma ESDI controller, based on doing a DejaNews search, it also looks like it _might_ be basically a rebadged WQESD controller, since the one article talks about WOMBAT. Is this correct, and can I just use my WQESD manual for it? Plessey P/N 705920-100A Quad Height, RAM board Zane | Zane H. Healy | UNIX Systems Adminstrator | | healyzh(a)aracnet.com (primary) | Linux Enthusiast | | healyzh(a)holonet.net (alternate) | Classic Computer Collector | +----------------------------------+----------------------------+ | Empire of the Petal Throne and Traveller Role Playing, | | and Zane's Computer Museum. | | http://www.dragonfire.net/~healyzh/ |

27 years, 2 months

5
5
0 0

The "FIRST PC" and personal timelines (Was: And what were the 80s

by CLASSICCMP＠trailing-edge.COM

>Or what would your definition of Micocomputer be? I suppose we have to >establish that first. graphic monitor and floppy drive, with hard drive >optional, would seem a good start. By those standards, even an IBM 5150 (aka "IBM PC") wasn't even a microcomputer. I think that sort of definition is way too narrow. Then a gain, I despise most any kind of exclusionary definition. But that doesn't leave one with much in the way of definitions left, does it? :-). I *do* like the web page that Sam pointed out ( http://www.blinkenlights.com/pc.shtml ). I may not agree with the final positive, but I do agree with all the previous negatives :-). And that Arkay CT-560 looks pretty nifty! Tim.

27 years, 2 months

8
17
0 0

How scarce (valuable) is core for the PDP-8?

by jdykstra＠nortelnetworks.com

I have several jars of ferrite cores made by IBM sometime in the late 1950's. I don't know exactly what size they are, but they can be hand-wired without a stereo microscope. I know, because I built a plane of 1x64x64 when I was in high school in 1971. (I was very determined to build my own computer.) The project was abandoned when I went away for college, which was probably a good thing, because my analog design skills were not up to creating the drive and sense circuitry. As I recall, I used something like #60 enameled wire. One of the challenges was stripping the insulation off the ends of the wires without damaging the copper. If anyone is seriously intending to build a demo core memory system, I'd be glad to provide a couple of hundred cores. I'd recommend something like a 16x16 array, unless you're looking for a project to make a 20-to-life sentence go faster. ---- John Dykstra jdykstra(a)nortelnetworks.com Principal Software Architect voice: ESN 454-1604 Enterprise Solutions fax: ESN 667-8549

27 years, 2 months

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More pdp-8 Docs Added

by kstumpf＠unusual.on.ca

Thank you man. Lots of work followed by lots of benefit. Yours in good faith. ---------------------------------------------------------------------------- ------------------------------- Kevin Stumpf * Unusual systems * www.unusual.on.ca +1.519.744.2900 * EST/EDT GMT - 5 Collector - Commercial Mainframes & Minicomputers from the 50s, 60s, & 70s and control panels and consoles. Author & Publisher - A Guide to Collecting Computers & Computer Collectibles * ISBN 0-9684244-0-6 .

27 years, 2 months

1
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PC Jr

by fpp＠concentric.net

On Mon, 26 Apr 1999, PG Manney wrote: > I recently acquired a PCjr with a bunch of software. Machine's very clean. > > I'm not really that interested in playing with this beast. Should I sit on > it as an investment? Is it worth anything now? Dnyone interested? It is a relative situation. Value is what is it worth to you or the buyer. A few points about the computer. There are not that many floating around for sale. It was a flop for IBM but it also was IBM's entr?e into the "Home computer" market. This gives it some weight. The PC and its siblings had supplanted the PC jr and nailed the lid on the coffin, but I would hang on to it, it will not become valuable for a while but it is a "place marker" in the history of computers. What did its introduction mean to the industry? Altair- first viable personal computer, Apple I computer, first of the longest lived manufacturer. (Yes IBM has been around longer but not as a PC maker) 1st Sony PC, the design and implementation of the 3.5" diskette, Tandy the first mass market machine not only sold in computer stores, Commodore Pet, First computer to make the cover of a national general circulation magazine (Popular Science) and from a calculator company no less; using calculator keys for the keyboard. The Commodore also set a standard for selling computers to computer dealers in their original selling agreements. Vector Graphics, first computer company founded and run by a woman. Osborne, the computer made by the guru of computer hobbyists and Kaypro, first generally accepted computer for the average business person. Want to know the value of a computer? Is it a piece of hardware or a point of computer history, did it change the way things were done? Good luck.

27 years, 2 months

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How scarce (valuable) is core for the PDP-8?

by Philip.Belben＠pgen.com

I wrote > BTW Siemens make some torroidal cores down to 1mm thick ferrite, slightly larger > in other materials. RS Components stock some - http://rswww.com/ and go in > through the catalogue: "Electronics", "Transformers/Inductors/Ferrites", > "Ferrites", "Torroids" (sic). There are even data sheets but I didn't manage to > download them. So it seems that RS and I made the same spelling mistake. I think "Toroid" and "Toroidal" are the correct spellings... P.

27 years, 2 months

1
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XXDP+ 2.5

by healyzh＠aracnet.com

NOTE: my problems are at the end of this message, got carried away to the extent someone might find this to have some useful info :^) I'm trying to run some tests on my /44 and have been having loads of fun with my lack of doc's on XXDP+. Note, for people in the same boat, I'd recommend Pete Turnbull's notes http://www.dunnington.u-net.com/public/XXDP.ps Though the best help I've found is having the doc's on the hardware I've tried to test. The /44 Tech Manual says to run 1-11 of the following tests in order (NOTE: I added the XXDP+ column). MAINDEC Operating Title XXDP+ 2.5 Diagnostic Sequence --------------- ------- ------------------------------- ----------- CKK FA <xy> 1 11/44 Diagnostic ROM* CKK AA <xy> 2 11/44 CPU/EIS KKAAB0.BIC CKK AB <xy> 3 11/44 Traps KKABD1.BIC CKK TA <xy> 4 11/44 Mem. Mgt. Prt A KKTAB1.BIC CKK TB <xy> 5 11/44 Mem. Mgt. Prt B KKTBD0.BIN CZM 9B <xy> 6 M9312/11/44 UBI Boot ZM9BE0.BIN CKK UA <xy> 7 11/44 UBI Map KKUAE0.BIN CKK KA <xy> 8 11/44 KK11-B Cache KKKAC0.BIC CZM SD <xy> 9 MSL-M/L Memory ZMSDD0.BIN MS11-L/M/P Memory Diagnostic ZMSPC0.BIC CZD LD <xy> 10 DL11-w/MFM SLU ZDLDI0.BIN CKK AC <xy> 11 11/44 Power Fail KKACC0.BIC CKF PA <xy> 12 FP11-F Part A KFPAD0.BIC CKF PB <xy> 13 FP11-F Part B KFPBC0.BIC CKF PC <xy> 14 FP11-F Part C KFPCD0.BIC CZK EE <xy> 15 PDP-11 CIS Instr. Exerciser ZKEEC0.BIC CZK UA <xy> 16 UNIBUS Systems Exerciser Diag. ZKUAE0.BIN CZK UB <xy> 17 UNIBUS Exerciser Module ZKUBC0.BIN *Included with the M7098 UBI module. CKFPA ||\/| || |Indicates a series of diagnostics: A= part 1, B=part 2, C=part 3, etc. || | (this is what the PDP-11/44 Tech Manual claims, I'm not convinced || | that it was followed) || Indicates a specific device tested by the diagnostic: || "FP" = Floating Point Diagnostic || "RK" = RK05 (disk diagnostic) |"K" indicates a specific diagnostic for the PDP-11/44 system. "C" indicates a PDP-11 diagnositic (not used on diagnostic disk pack or magnetic tape). <xy> = x = Revision Character (alpha) y = Patch Number (0-9) My single biggest problem seems to be stopping a diagnostic once I've started it. So far I've been resorting to stopping the CPU and rebooting, but one would think that there must be a better way, and that I've missed it. My second problem is the first test, I can't find a KKFA*.* test. Is there another test I can run on the diagnostic ROM? #3 is #3, but I think this is proper behavior CKKABD0 11/44 TRAPS NO FLOATING POINT OPTION PRESENT NO CIS OPTION PRESENT CONSOLE 17777707 023252 >>> Problem #4 isn't that big a deal, the "M9312/11/44 UBI Boot" diagnostic complains that the DD and DL ROMS are in as DL and DD, while it wants DD and DL. #5 may or may not be a problem with the cache (real problem is my not knowing how to interpret it). CKKKAC0 11-44 KK11B CACHE RMI REGISTER (G5179) NOT USED-SKIP HI ORDER BIT ADDRESS TEST UNIBUS EXERCISER NOT USED-DMA TESTS NOT PERFORMED END OF PASS # 1 END OF PASS # 2 END OF PASS # 3 <etc,etc,etc> I solved #6 by finding and substituting the ZMSPC0 memory test for ZMSDD0. Opps, guess I didn't try step 11, and 12-14 can't be done at the moment as the FP11 isn't installed, and I don't have a CIS for #15, 16&17 both complained. Zane | Zane H. Healy | UNIX Systems Adminstrator | | healyzh(a)aracnet.com (primary) | Linux Enthusiast | | healyzh(a)holonet.net (alternate) | Classic Computer Collector | +----------------------------------+----------------------------+ | Empire of the Petal Throne and Traveller Role Playing, | | and Zane's Computer Museum. | | http://www.dragonfire.net/~healyzh/ |

27 years, 2 months

1
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Mystery UNIBUS Boards?

by jrbrady＠mindspring.com

Greetings All, Can you help identify these UNIBUS boards? They were found in a BA11-K expansion box in a VAX 11/750. The VAX was used to run the equipment in an MRI trailer. I didn't remove the system and don't know to what type of equipment it was originally connected. 1) Full size genuine DEC hex board, no "M" number on spine. "DIGITAL" and "BSWU-T" etched on front. Two stickers, marked "835084" and "4522 117 2760". 93 TTL chips, 18 PAL chips, 5 DIP switch blocks, two 50-pin connectors for ribbon cables. On rear side, "4522 111 91963" etched and a sticker with "PR32.4B" and "MB6024ET". 2) Plessey Peripheral Systems quad board. Marked with "P/N 703680- 100E" on front, "703679-001 REVB" on rear. 7 chips with stickers "218 101C, 102C, 103C, 104C, 105C, 100 UK30, UK2A". 62 TTL chips. 1 50-pin connector with cable to what appears to be an interface board (#3 below). 3) 8" by 10" board connected to Plessey board above. 2 50-pin connec- tors on top. Etched with "C-FTR", "FDD-FTR", "FTR-FTR". 12 26LS31 & 32 chips, 10 TTL. Instead of card-edge fingers, has 2 3-level male 3x32 pin AMP3485 connectors which plug into corresponding female receptacles in BA11-K box (one group of hex slots replaced with these). Any help identifying these boards is appreciated. Doubt I'll ever use them, but nice to know what they might be! BTW - Posted this inquiry to comp.sys.dec & alt.sys.pdp11 awhile back so it may look familiar. Thanks, Jason Brady jrbrady(a)mindspring.com Lynnwood, WA

27 years, 2 months

1
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TRW Swaps/CompuCrawls

by jpl15＠netcom.com

Well.. amplifying what Sellam has written... the very first SoCal CompuCrawl is in the history books. It takes up about two sentences. ;} The Gathering was small but intense... we had big fun, tho. I gave away some lonely equipment to a Good Home, and we played with some of my Geek Toys. I got a cool t-shirt with 'GEEK' emblazoned boldly for all to see and snicker at. Marvin behaved himself for the most part, and law enforcement assistance was thankfully not required at any time during the entire soiree. Since there were several of Us who apparently had to cancel at the last minute, I am strongly considering having another next month, instead of next quarter (september) as I had originally planned. Also, various folks mentioned to me that logistics and/or transportation issues affected their participation. Anyone needing a ride to-from should contact me directly and we'll sort it out. So again: if there is any interest between now and the next SoCal TRW swap meet, on the last Saturday of May (the 29th? 30th?) from local and visiting Listmembers, I will again hold a Vintage Computer open house after the TRW swapmeet and post-swap Brunch, and thereafter, quarterly. Mark Your Calendars! (Use spray paint this time) Cheers John

27 years, 2 months

1
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PC Jr

by manney＠hmcltd.net

I recently acquired a PCjr with a bunch of software. Machine's very clean. I'm not really that interested in playing with this beast. Should I sit on it as an investment? Is it worth anything now? Dnyone interested? Thanks P Manney Is it illegal to yell "Movie!" in a fire station? Thousands of discounted photo items at http://www.hmcltd.net/pgphoto

27 years, 2 months

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More pdp-8 Docs Added

by mcquiggi＠sfu.ca

Hi All: Ten more scanned documents added to the http://highgate.comm.sfu.ca/pdp8 web site tonight. Kevin --- Kevin McQuiggin VE7ZD mcquiggi(a)sfu.ca

27 years, 2 months

1
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Old computer books? Oh, we shred them!

by guerney＠uq.net.au

Every two years at this time the University of Queensland Alumni Association holds a large sale of old books donated by individuals plus library discards. I've found some good collectables there in the past, such as old manuals, but this time (today) it took me five minutes to just find where the computer books were - instead of a full trestle table top as in previous years, there was just 4 inches of space reserved for them - maybe 20 books in a hall of many many thousands. I found the lady in charge and asked what had happened to them? She said "we kept any computer books dated in the 50's or 60's (I didn't find any), and anything fairly recent, but all donations from the 70's and 80's went out." I asked "Did you send them to one of the charities to sell at their bookfests?". Her response "oh no, they just go straight to the shredder! - we can't get rid of them otherwise." And sadly, I suspect she was correct. Besides the odd character like me looking for manuals for long gone models, most of the stuff that went out for sale was rubbish to 99.99+% of people and stayed on the table at the end of the day. But I sure wish she had at least given me the chance to look through that stuff before it hit the shredder. The good news was that I found amongst the "sets" (encyclopedias etc) a full set (I think, 22 volumes anyway) of the Time-Life series Understanding Computers. Lots of good computer history and pictures - but I would be interested if anyone has any criticism of the facts presented in any of the articles in that series - they seem authoritative enough, but then some of the people on this list know more than the usual sources that Time-Life writers would have used. Phil in Brisbane, Australia.

27 years, 2 months

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PC question

by mbg＠world.std.com

Yesterday, at the KS10 move, I came away with two IBM PCs, but I don't know enough about them to know if they are the AT or XT models... they both have a 5.25" floppy and a hard drive, and both have color monitors. They are both desktop boxes... the monitors were sitting on top of them. So, how do I tell... Megan Gentry Former RT-11 Developer +--------------------------------+-------------------------------------+ | Megan Gentry, EMT/B, PP-ASEL | Internet (work): gentry!zk3.dec.com | | Unix Support Engineering Group | (home): mbg!world.std.com | | Compaq Computer Corporation | addresses need '@' in place of '!' | | 110 Spitbrook Rd. ZK03-2/T43 | URL: http://world.std.com/~mbg/ | | Nashua, NH 03062 | "pdp-11 programmer - some assembler | | (603) 884 1055 | required." - mbg | +--------------------------------+-------------------------------------+

27 years, 2 months

11
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HP1000M

by jlwest＠tseinc.com

Hum.... Thanks for the tip on the seller! My M series is sick, so I was just getting ready to fire off an email asking what cards were in the memory backplane.... with a record like that, I don't think I'll bother (now if it was a 7900A drive, I'd forge ahead anyways <grin>)! Jay West

27 years, 2 months

1
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Power connectors

by Philip.Belben＠pgen.com

>> Hey, Sallam, couldn't this power thing be a good addition for >> VCF 3.0? A speach about how to operate Eq. from a different >> country (and power system) in an acceptable and safe fashion ? >> Maybe if Philip and me (possible with a thirs, US guy) team up >> to give an outline of the different circumstances to remember >> when using foreign (old) computers ? There might be some need. > > Yes, I think this would make for a great workshop. I expect more people > to start trading computers across the world and this will make for a very > relevant discussion. I think it's an excellent idea. In fact I have long thought a computer-buff's guide to power electrics (the mains) would be worth writing. But I doubt I'll manage VCF 3 this year. A holiday in CA is not something I do every year, alas... Philip.

27 years, 2 months

2
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Powerlines

by danburrows＠mindspring.com

>2. Phase. > >As I understand it the usual practice in the US is take _either_ a phase and >earth (neutral) _or_ two phases of the HV supply and feed a single phase >transformer from this. The LV side of the transformer is (say) 240V with a >centre tap. The centre tap is earthed and provides the neutral connection, the >outer two taps are then both hot at 120V, 180 degrees apart. This is true _even >if_ the primary (HV winding) is connected between two phases of the HV 3-phase >system. Close but not quite right. For single phase installations the power company supplies 2 hots and neutral. This is a center tapped secondary and the neutral is earthed at the service entrance. The primary of this transformer is fed from only 1 high voltage phase. >In the UK the usual practice is to connect all 3 phases of the HV (almost >invariably 11kV phase to phase) to a delta-star 3-phase transformer. The >secondary, the star-connected winding provides 3 phases and neutral. Neutral is >earthed at the transformer. Protective earth can be provided by _either_ a >separate wire from the main earth at the transformer _or_ an earthing electrode >at each customer's site _or_ the neutral is earthed at a large number of points >on the system and the customer's protective earth is bonded to neutral at the >point of entry of the supply. In all cases the customer sees 240V line to >neutral; if he gets more than one line (hot) connection, they will be 120 >degrees apart. The delta-star is the same but with 120 phase to neutral and 208 phase to phase. In the UK it is the same but 240 phase to neutral and 416 phase to phase. You can also commonly find 480 3 phase delta- star 277 phase to neutral. This is then used for lighting (277 florescent is common) and large loads like air conditioning. In these installations the customer has to provide their own transformer to 208/120. >In remote locations, only 2 phases of the 11kV system are taken to the site. >Small loads get a single phase 11kV/250V transformer with one end of the LV >earthed; larger loads get a single phase 11kV/500V transformer with a centre tap >earthed. Some farm equipment (I am told - I have never seen this) is rated for >480V single phase. I don't think this is avail. in the US. > >It is very unusual for a domestic installation to get more than one phase and >neutral. But 3-phase can be done - the supply company don't mind putting it in >if they think you'll buy a lot of electricity! They will here also and I checked into getting it here but I am a few miles >from the closest point that 3 phase is available for distribution. I would either have to guarentee a large $ per month usage or pay them to add the additional lines. Over $10,000 was mentioned. Dan

27 years, 2 months

2
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Some things make me want to toss my cookies ...

by cmcmanis＠freegate.com

http://www.bccc.com/nancy/memorydress.html

27 years, 2 months

5
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DEC documentation RUMOR????

by clintw＠colorado.cirrus.com

Hi all, I read a web page somewhere that indicated DEC put in the public domain all the documentation they no longer publish. Is this true? Can anyone point me back to the original web page? Thanks, clint

27 years, 2 months

2
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Cores, light bulb goes on ...

by allisonp＠world.std.com

<Ok after spending much of the weekend trying to get my core driver working <and feeling really good about having all the parts I needed in my spares <box, I realized I had built half of an h-bridge. Since I had already <designed a really nice MOSFET based h-bridge that could switch 10 - 15 amp <for my robots I slapped my head and went "Doh!" ;) that will do. <Anyway, so I wired up my #2 nut with sense wire to the h-bridge and start <slapping current back and forth through my nuts. :-) Seriously though when <viewed on 'scope it looks something like: < < +--+ < | | <Ch1 -+ +----+ +----- < | | < +--+ < +--+ <Ch2 -+ +----+ +----- < +--+ Transformer action prior to saturation. <UNTIL you get to about 7.5 amps or so, and then it looks like: No you know what nuts dont work... < +--+ < | | <Ch1 -+ +----+ +----- < | | < +--+ < +--+ <Ch2 ---+ +----+ +----- < +--+ < <So I stared at it a bit and the little bulb went on between my ears. < <The first pulse "writes" a zero to the core, if the core is either already <magnetized with a zero, or has nothing in it, then the sense line sees the <deta-B (change in magnetic field) and a current is induced in the wire. <When the second pulse comes along it "writes" a one into the core, same <effect on the sense wire. The clever part comes when your "write" a zero t <a core that has a one already written to it. Core is one of the few DESTRCUTIVE READ memories. You have to try and flip it to see if it flips, if it does you had a (one or zero) and if didn't you have a (zero or one). Designing circuits the transformer and the "bistable" properties makes for interesting logic. <In this case the current in the wire induces its standard magnetic field, <but that field is _cancelled_ by the field already in the core, thus for a <period of time the sense line sees no change in magnetic flux, and so no <current is induced. Then however the core switches to 0 and the sense wire <sees that change in flux and out comes the induced pulse now delayed from <the initial point by a time controlled by how long it took to saturate the <core and switch it. Yep. Watching that spring snap in interesting on a scope. Those nuts are slow too! Try a bunch of other materials now that your set up... <The gap between the pulse start and the sense pulse is used to tell whethe <or not the core had a 1 in it. Now in the DEC design what happens after th <read pulse (which is really a "write zeros" pulse, is they take the data <they just read and re write with the write ones pulse. However this time <since the sense lines aren't needed to figure out what the cores had in <them, they use them for "inhibit" currents. They used seperate wires (four wire cores) in some cases as it was easier that all that switching. <-------------------------- <Cool stuff, now it raises some new questions: < 1) Do you want your pulses to be long enough to switch the < core exactly, or longer? (eg does writing a zero just cancel < a one or does it cancel the one and write a zero in its place?) I forget. < 2) Why not just gate the write one current pulse? That would save < on the inhibit current stuff. well you have to know what your writing back and to do that you have to read it first. Hence the common write after read cycle on many machines >from the era of core. < 3) What properties of a material make it easier to switch at lower < currents? I don't want to build a core plane with nuts if I need < 8 amps to switch them. Good magnetic conductors that hold their magnetizm. Some steels, ferrites, cobalt alloys, alnico, a few rare earths. Try some of those ferrite beads used for bypassing in RF work. Allison

27 years, 2 months

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How scarce (valuable) is core for the PDP-8?

by allisonp＠world.std.com

<OK, how about it. Put a ring of compasses around the wire with needles str <enough magnetised that they will stay pointing N-S around the ring regardle <the Earth's field. < <Can you then flip them with a current? A very good visual demonstration of <core works! Yep, That would be good to watch but that's really a demo of the fields around conductors (imporant building block). Allison

27 years, 2 months

1
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HP 1000 on eBay : auctioned by unresponsive bidder

by ss＠allegro.com

Hi, I was about to send this just to ccauction list, but I realized that some ClassicCmp readers might not read ccauction ... and they might have an interest. In a rather misleading title: "antique Altair-like HP-1000 M-series computer" dschambe(a)uiuc.edu is selling a partially gutted HP 1000 computer. http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=95719221 This seller has consistently refused to respond to my email about two items that I got for low bids on prior auctions...so I have never been able to finalize the purchase. If anyone from this list does bid on the HP 1000, and wins, please encourage this guy to honor his *existing* committments before sending him money! thanks! sieler(a)allegro.com

27 years, 2 months

2
1
0 0

Cores, light bulb goes on ...

by cmcmanis＠freegate.com

Core memory, the saga continues. Ok after spending much of the weekend trying to get my core driver working, and feeling really good about having all the parts I needed in my spares box, I realized I had built half of an h-bridge. Since I had already designed a really nice MOSFET based h-bridge that could switch 10 - 15 amps for my robots I slapped my head and went "Doh!" Anyway, so I wired up my #2 nut with sense wire to the h-bridge and start slapping current back and forth through my nuts. :-) Seriously though when viewed on 'scope it looks something like: +--+ | | Ch1 -+ +----+ +----- | | +--+ +--+ Ch2 -+ +----+ +----- +--+ UNTIL you get to about 7.5 amps or so, and then it looks like: +--+ | | Ch1 -+ +----+ +----- | | +--+ +--+ Ch2 ---+ +----+ +----- +--+ So I stared at it a bit and the little bulb went on between my ears. The first pulse "writes" a zero to the core, if the core is either already magnetized with a zero, or has nothing in it, then the sense line sees the deta-B (change in magnetic field) and a current is induced in the wire. When the second pulse comes along it "writes" a one into the core, same effect on the sense wire. The clever part comes when your "write" a zero to a core that has a one already written to it. In this case the current in the wire induces its standard magnetic field, but that field is _cancelled_ by the field already in the core, thus for a period of time the sense line sees no change in magnetic flux, and so no current is induced. Then however the core switches to 0 and the sense wire sees that change in flux and out comes the induced pulse now delayed from the initial point by a time controlled by how long it took to saturate the core and switch it. The gap between the pulse start and the sense pulse is used to tell whether or not the core had a 1 in it. Now in the DEC design what happens after the read pulse (which is really a "write zeros" pulse, is they take the data they just read and re write with the write ones pulse. However this time since the sense lines aren't needed to figure out what the cores had in them, they use them for "inhibit" currents. Remembering that the cores were all written to zero by the 'read' when the write 'ones' pulse comes along you don't want it writing cores that you want to keep zero (they had zero before). So a current that is in opposite direction of the write current is sent down the sense lines where zeros should be kept. The magnetic field generated by these "inhibit" currents cancel the magnetic field created by the "write ones" current and thus prevents those cores with a 'zero' in them from being written to '1'. -------------------------- Cool stuff, now it raises some new questions: 1) Do you want your pulses to be long enough to switch the core exactly, or longer? (eg does writing a zero just cancel a one or does it cancel the one and write a zero in its place?) 2) Why not just gate the write one current pulse? That would save on the inhibit current stuff. 3) What properties of a material make it easier to switch at lower currents? I don't want to build a core plane with nuts if I need 8 amps to switch them. --Chuck McManis

27 years, 2 months

1
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FW: VAX 6500 in Minneapolis.

by kstumpf＠unusual.on.ca

PLEASE REPLY DIRECTLY TO THE AUTHOR OF THE ORIGINAL MESSAGE. >Reply-To: <kenp(a)trlab.com> >From: "Ken Peck" <kenp(a)trlab.com> >To: <kstumpf(a)unusual.on.ca> >Subject: Computer Hardware for Museum >Date: Mon, 26 Apr 1999 16:28:02 -0400 >X-MSMail-Priority: Normal >Importance: Normal >X-MimeOLE: Produced By Microsoft MimeOLE V4.72.3110.3 >X-UIDL: e7780be67b36c9d8688e16fdc0bca942 > >Kevin, > >There is a Vax 6500 in Minneapolis, >Minnesota that will be de-installed in June. I thought perhaps there might >be some interest in the historical value of it for some collector or museum. >If you or someone you know might be interested, please let contact me. > >Regards, > >Ken Peck >Total Renal Laboratories, Inc. >1991 Industrial Dr. >Deland, Fl. 32724 >800.604.5227 > > > ---------------------------------------------------------------------------- ------------------------------- Kevin Stumpf * Unusual systems * www.unusual.on.ca +1.519.744.2900 * EST/EDT GMT - 5 Collector - Commercial Mainframes & Minicomputers from the 50s, 60s, & 70s and control panels and consoles. Author & Publisher - A Guide to Collecting Computers & Computer Collectibles * ISBN 0-9684244-0-6 .

27 years, 2 months

1
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The "FIRST PC" and personal timelines (Was: And what were the80s

by edick＠idcomm.com

The previous comment should have made it obvious it was NOT within the reach of the "average" American. First of all, it was over a month's pay for the average American, it was equivalent to six months' groceries for a family of four, and you could get a refrigerator or a washer, neither of which were routine discretionary expenditures for the "average" American of that time. That was during and immediately after the Korean war, when a 4-bedroom house on a 1/4-acre lot cost $4600. That same house, now, in California would cost you $4600 a month to rent. People's attitudes about what's important enough to spend your money on have changed considerably. $300 was not an expenditure an "average" American would consider lightly in 1952. That was the year I came to this country. There was an election between Adlai E. Stevenson (Democrat) and Dwight D. Eisenhower (Republican). It was BEFORE the first test of a hydrogen bomb. People weren't crazy then as they are now . . . and all the loose nuts hadn't yet learned to run to California. Dick -----Original Message----- From: Sellam Ismail <dastar(a)ncal.verio.com> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Thursday, April 22, 1999 10:16 PM Subject: Re: The "FIRST PC" and personal timelines (Was: And what were the80s >On Thu, 22 Apr 1999, Richard Erlacher wrote: > >> No, what's relevant isn't the technology and its state of maturity, but the >> comparison of the relative value of the numbers. Today, it's just assumed >> that if you buy an item for $300 and it subsequently breaks, you shrug your >> shoulders and throw it away. Back in the '50's, not many people were silly >> enough to do that. > >So what? $300, even back in the 50s, was still realistically within the >price range of the average American. A multi-million dollar mainframe was >not. $300 vs $$$millions is a significant difference. > >Sellam Alternate e-mail: dastar(a)siconic.com >--------------------------------------------------------------------------- --- >Don't rub the lamp if you don't want the genie to come out. > > Coming this October 2-3: Vintage Computer Festival 3.0! > See http://www.vintage.org/vcf for details! > [Last web site update: 04/03/99] >

27 years, 2 months

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