test-drb

test-drb@ccmp.vtda.org

101090 discussions

by rigdonj＠intellistar.net

Who was I supposed to copy the IBM AT Tech Ref manual? I lost your message. I've made the copy, let me know who you are. Joe

26 years, 8 months

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

by ethan_dicks＠yahoo.com

--- John Dykstra <jdykstra(a)nortelnetworks.com> wrote: > 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. Cool. > 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. Heat? Chemicals? Friction? > 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. I'm serious. I really have wanted to build something like this. In terms of size, the problem isn't the wiring, it's the redundant circuitry. -ethan _________________________________________________________ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com

26 years, 8 months

1802 data sheets: was old data books

by CLASSICCMP＠trailing-edge.COM

>> Good - if you can find some RCA file numbers for the 1801's in there >> for Eric, this'll be a huge step forward in getting the 1801 data sheets >> from RCA and/or Harris. >I know I have nothing on the 1801. It was phased out completely by RCA >in '77 or so. You looked through your 1802 stuff and didn't find a single reference to any 1801 literature? Often just having the reference lets you go to the local EE department and find the appropriate volume in their library (Many departments do have books going back to the early 70's) or in the personal library of one of the faculty members. Unfortunately, little of this stuff is in an online database anywhere, so you really have to do the legwork to track it down. I spent most of my academic career doing such legwork - it's been decades since many of the best tables of thermal neutron cross sections have been published, and I found many of them in dusty corners of little- used labs. Incidentally, I found my HP9100B while searching dusty corners for neutron cross section tables :-). -- 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

26 years, 8 months

1802 data sheets: was old data books

by CLASSICCMP＠trailing-edge.COM

>> If you want to continue the search further, Harris has online data >> sheets for much of the CDP18XX series (including the classic 1802 >> interface and memory parts), and maybe one of these will have a file >> number for an 1801 data sheet. After you get a file number, you can >> usually have the folks at Harris fax the data sheet to you. >I have full 1802 docs from back when the elf article was published. Good - if you can find some RCA file numbers for the 1801's in there for Eric, this'll be a huge step forward in getting the 1801 data sheets >from RCA and/or Harris. >The 1801 series was a less dense (hence teo chips) version of the 1802 >and was discontinued with the advent of the 1802 back around '76. Yep - this is why you need the file number before you can get any further. The data probably exist in paper form, but aren't indexed in any of the on-line databases that the manufacturers still have. It's like getting obsolete parts from DEC; first you have to convince yourself that such a part still exists, then you have to find the part number, and then you often find it's an off-the-shelf item even though it might not have been produced for 20 years. (Examples of stuff I've ordered in the past few years are RX02 and RL02 drive belts, and even a can of Magna-See.) In the case of DEC parts, having a dumpster-dived copy of the "Option/Module Hardware List" stamped "DEC Confidential" all over it helps a little bit :-). -- 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

26 years, 8 months

Sun 1 question

by CLASSICCMP＠trailing-edge.COM

>How can I identify Sun 1 cards? There's a rough equivalent to the "DEC Field Guide" for Sun systems. It's the "Sun Hardware Reference", and is by James W Birsall, and (at least it used to) is posted to somp.sys.sun.hardware semi-regularly. One version on the web is at http://stumbo.vm.com/~techrat/faq_hardware/hwref0.html Part 1 is a brief introduction to the various Sun models and backplanes, and Part 3 contains many Multibus board numbers. -- 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

26 years, 8 months

Sun 1 question

by Innfogra＠aol.com

How can I identify Sun 1 cards? Paxton

26 years, 8 months

The Paxton auction: any interest in rescues

by CLASSICCMP＠trailing-edge.COM

>Andromedia Systems Dual 5 1/4 floppy disk drive, DDMDS-B, SN 21. Could this >be for DEC equip. Almost certainly. Does it have a 34-pin connector on the back? Some of the Andromeda controllers took a "breakout board" that separated the floppy signals from the hard disk signals, but the pre-breakout-board cable was (AFAIK) always wider than 34 pins. Tim.

26 years, 8 months

driving prices down?

by yakowenk＠cs.unc.edu

I just had an idea. One of the things pushing up e-bay prices is the publication of the high bids of past auctions. The logic for sellers is something like, since the previous one sold for this much, I should expect at least as much for this one. What if we kept (and publicized) a record of asking prices for the things that did *not* sell? Maybe buyers would look at that, and use similar logic to avoid bidding any higher than that? Bill.

26 years, 8 months

Connecting CSA's Transputer Education Kit to an Inmos B008

by rmeenaks＠olf.com

>> >> Hi, >> >> I have several B004-style CSA Transputer Education Kits (aka TEKs) that use >> an 8-pin minidin connector for its link (compatible to apples printer >> cables). Is there any way for me to connect these nodes to an inmos B008 >> motherboard's 37-way external connector?? Thanks. > > >If they're standard Transputer links, then sure. Have you tried tracing >the pins on the 8 pin miniDINs to see what they're connected to (like >link pins on the transputer)? Reset/error/analyse could be harder to >trace (since they'll possibly go to PALs), but you should be able to >figure something out by which are inputs/outputs. > Actually, I have full details on how to connect (with pinouts) TEKs to other transputer motherboards including INMOS', but not the INMOS B008. Apparently, the specs mention a 5x1 connector (or is it a 5x2) on inmos boards that can be used to connect the TEK to, but since I don't have a B008 yet (coming in the mail anytime now), I can't verify if this type of connector exists on it. I will send out full details once I am at home with all the pinouts etc. Ram

26 years, 8 months

1802 data sheets: was old data books

by CLASSICCMP＠trailing-edge.COM

>Speaking of which, sometime back I failed to convince a surplus to sell >me a really old RCA databook which contained information on the two-chip >predecessor of the 1802, which went by the numbers CDP1801R and CDP1801S >if memory servers. > >Anyone have the book or data sheets? I'd love to get copies. Hmm, this doesn't help you much, but I did a bit of poking around, and here's what I came up with: Harris, the current producer of the 1802, has the following documents online: Application notes: AN6565 Design of Clock Generators for Use with COSMAC Microprocessor CDP1802 http://www.semi.harris.com/data/an/an6/an6565/ CMOS CPU Data sheets: CDP1802A \ CDP1802AC| http://www.semi.harris.com/data/fn/fn1/fn1305/ CDP1802BC/ High-Reliability 8-bit CMOS Processor data sheets: CDP1802AC/3 http://www.semi.harris.com/data/fn/fn1/fn1441/ I briefly paged through the above data sheets to see if they might have file numbers for any of the 1801 data sheets, but didn't see any. It was interesting to see that at least some of these classic parts are now available in PLCC's (I suppose this is the modern equivalent of the Flat-Pack, roughly speaking.) If you want to continue the search further, Harris has online data sheets for much of the CDP18XX series (including the classic 1802 interface and memory parts), and maybe one of these will have a file number for an 1801 data sheet. After you get a file number, you can usually have the folks at Harris fax the data sheet to you. -- 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

26 years, 8 months

Repairing core

by ethan_dicks＠yahoo.com

--- Bill Yakowenko <yakowenk(a)cs.unc.edu> wrote: > So what kind of wall hanging is more appropriate for a geek? I have, mounted on a board over the door, a slide rule entitled "In Case Of Emergency". It was my father's when he was in college. -ethan _________________________________________________________ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com

26 years, 8 months

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

by allisonp＠world.std.com

<One plastic box is labeled "Univac memory elements" and has a small sample <of 3 size cores. The largest is about 1mm O.D. and the smallest is less <than half that size. They look very fragile as the I.D. is almost as large <as the O.D. Those are about the size of the 8E cores. <The other is a "Indiana General 15 mill memory plane" I guess the cores ar <15 mill diameter. There are 16 cores wired as a 4x4 plane. The wires are Big fat ones... not really. Those planes would be easy to drive and understand. that would be one I'd love to try. <much smaller than 30 SWG (about 28 AWG). I would say much smaller than 50 <(either) gauge, I need a magnifier just to see them. I'd have guessed thinner than #40. Allison

26 years, 8 months

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

by pete＠dunnington.u-net.com

On Apr 20, 16:04, Chuck McManis wrote: > I'm not sure I parsed this. At my local hardware store the nuts were made > of Zinc (not steel) and but the washers were made of "soft iron" which I > thought meant there was a _lower_ carbon content than "steel" washers. (The > washers are designed to be compliant whereas the nuts are quite hard) Zinc isn't a hard metal and it's only weakly ferromagnetic (doesn't stick to a magnet). The nuts you found are zinc-plated steel, probably what we call BZP (bright zinc plated). Soft iron sometimes has quite a high carbon content, and a very variable silicon content (which affects its magnetic permeability). The composition of "soft iron" varies quite a lot, whereas although different types of steel have different compositions, the composition of any given type is fairly standard (and in some cases very precisely controlled), and usually quite low in silicon. -- Pete Peter Turnbull Dept. of Computer Science University of York

26 years, 8 months

z80 timing... 6502 timing

by yakowenk＠cs.unc.edu

On 19 Apr 1999, Richard Erlacher <edick(a)idcomm.com> wrote: ] It's true that may be more interesting when you have different vehicles, but ] if you're trying to determine which of two is faster, don't you focus on ] those two? Having lots of variations in the hardware only tends to muddy ] the water. Obviously, some of us care about vehicles other than those two. Doesn't muddy _my_ waters one bit. :-P I, for one, am interested in processor capabilities independent of video/disk/etc gorp. Roman numerals isn't going to be a thorough comparison, but it's better than nothing, and small enough to be fun. If this is still going on in a month or two, maybe I'll write an entry myself. As it is now, my schedule barely allows me to keep up with all the stuff you guys are writing! And then, later the same day, regarding my suggestion about noting the relative ages of processors when comparing their results, he wrote: ] It's pretty hard to imagine how a limitation like your suggestion would ] apply. Newer processors addressed weaknesses in the older ones. One of ] those was ease of programming. In some cases, e.g. the 6809, the processor ] was designed with a regular instruction set and lots of addressing modes so ] as to make generating code easy. It didn't necessarily make it faster. I ] don't know how elegant such code will ultimately turn out to be. If you want to get a handle on which processors were really better than others performance-wise, you look at the best they can do on some specific problems. Granted, the results may not be easy to interpret because of varying environmental characteristics. Welcome to Earth. Nothing is simple here. Obviously, if the 6809 loses to some older processor, its adherents can still claim ease-of-coding as a benefit. But it would still be interesting to know if it could regularly get whomped by a measly, pathetic, sad-excuse-for-a-processor like the 6502. :-) :-) :-) :-) My suggestion was not meant as any sort of limitation, just my take on what kind of result would be interesting; one way of interpreting the results. If an older processor doesn't do as well as the newer one, well, we expected that. But if an older one outperforms a newer one, there is something worth exploring there, a lesson to be learned about an improvement really wasn't. Bill.

26 years, 8 months

Has anybody heard from Wirehead?

by bill＠chipware.com

Hate to use the list for this purpose but he doesn't seem to be responding to any email lately. Does anybody know why? Thanks, Bill Sudbrink

26 years, 8 months

Semi OT: Twitching Mac pointer

by healyzh＠aracnet.com

Has anyone ever seen a pointer on a Mac start to twitch? Mine seems to have started jiggleing back and forth slightly. Really disconcerting. Any ideas on if this is the mouse, or the machine :^( It seems to have something to do with how the cord is twisted, so I'm suspecting that the wires are getting a little frayed :^( When I smooth the cable out, it seems to stop. 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/ |

26 years, 8 months

DEC BC11A-15 Cable

by danburrows＠mindspring.com

>Am I correct that this is used to connect the UNIBUS backplane in one >chassis to a UNIBUS backplane in another chassis? Yes. Do you need any? I have several different lengths here. The -15 is the length in feet IIRC. Dan

26 years, 8 months

heads up; OSI Challenger 1P

by allisonp＠world.std.com

<I would call 115V 30A a common business circuit; it's certainly exceedingl <common on minicomputer power controllers. What else do folks plug the <Twist-N-Locks on their DEC 861C power controllers into? Special. Most places where I've seen systems installed for the first time that circuit had to be added. Even at DSG, PK3 and the Mill I had to have facilities add circuits for some things as that was not the normal distribution in the lab areas. My reference was that the average business and building unless prepped will only have 15 or maybe 20A outlets in place. Older buildings those will be in short supply. Then again NYC is where I have most of that experience. Allison

26 years, 8 months

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

by allisonp＠world.std.com

<generator set up to drive a fast rise time buffer amp (so I can get a <reasonable amount of current) what else do I need to do to verify that I'v <successfully "flipped" the device. (My first guess would be a garden <variety compass) first you need a waveform that looks like this.... _____|-----|_____________ _______+I |_____| -I And put about one turn through the ferrite or steel under test. Then you'll need a second 1-2 turn loop hooked to the scope. You'll know the right waveform when the signal starts showing a huge amplitude difference as switches. Allison

26 years, 8 months

Power connectors

by danburrows＠mindspring.com

>First, to get common names: >Hot = one Phase >Neutral = Protective Ground >Ground = Ground (the starpoint on 3 phases connected to earth at the 'generator') That explains the confusion. In the US: Hot is one phase and in single phase systems you can and do have 2 hots. Neutral is what you are refering to as ground. The starpoint for both single and 3 phase. Ground is the protective / frame ground. The protective ground (ground in US codes) is not allowed to normally carry any current. It should be able to be temporarly disconnected and not create a hazardous condition. >Second, do I understand that US appliances got fuses on both wires >and both are switched ? On 240 volt equipment yes. The 120 volt plugs are defined with distinct Hot, Neutral and ground pins. I am familiar with your plugs also and have wondered how hot / neutral definitions are handled. Think of US 120V plugs like UK plugs just smaller and without fuses in them. >Over here in Germany only one wire is >switched and protected with a fuse, althrough it is not defined >which one is the 'hot' line, since our connector is symetrical >- there is no way to insert the plug in a way where the Hot and >the Ground side is defined - Our plug isn't inherited from the >DC times, but rather a new design when 220V AC became standard >in the 30s, to fit the needs of (and only of) AC Eq. The US did not used to make a distinction between hot and neutral until about 30 years ago when they added the "protective" ground pin. Now they are keyed. If you look closely at a receptacle, one blade is wider - neutral, The narrower blade is Hot and the round pin is protective ground. Some "equipment" uses only 2 wires. The blades and often one is larger to assure that it is polarized correctly. These polarized plugs have come into common usage in the last 20 years. Dan

26 years, 8 months

Power connectors

by Philip.Belben＠pgen.com

>> >First, to get common names: >> >Hot = one Phase >> >Neutral = Protective Ground >> >Ground = Ground (the starpoint on 3 phases connected to earth at the >> 'generator') > >> That explains the confusion. In the US: >> Hot is one phase and in single phase systems you can and do have 2 hots. >> Neutral is what you are refering to as ground. The starpoint for both >> single and 3 phase. >> Ground is the protective / frame ground. Yes. In the UK, "Hot" is usually referred to as "Live", and until 1992 this was the official term. In 1992 the term was changed to "Line", so that the phrase "Live parts" could be introduced to mean any conductor connected to the electrical supply (i.e. not including the protective ground, which is called "Earth") >> >Second, do I understand that US appliances got fuses on both wires >> >and both are switched ? >> On 240 volt equipment yes. > > Ahh ja - we also use fuses in each 'Hot' wire - so if you have a > 3~ installation, 3 fuses are to be installed _and_ they have to > be tied (mechanical), so if one blows all 3 will go off. In the UK it is similar, although I don't think there is a requirement for fuses to break all three phases for a fault on one. Since the US has many 240V centre-tapped-to-ground installations, 240V would have fuses in both lines (both hot) but none in neutral. ISTR the neutral wire in some 240V equipment (cookers are an example that springs to mind) is used instead of protective ground, which makes me a little uneasy. >> >Over here in Germany only one wire is >> >switched and protected with a fuse, althrough it is not defined >> >which one is the 'hot' line, since our connector is symetrical >> >- there is no way to insert the plug in a way where the Hot and >> >the Ground side is defined - Our plug isn't inherited from the >> >DC times, but rather a new design when 220V AC became standard >> >in the 30s, to fit the needs of (and only of) AC Eq. Hans, I think you've gone some way to answering your own question here. See below. >> The US did not used to make a distinction between hot and neutral until >> about 30 years ago when they added the "protective" ground pin. Now they >> are keyed. If you look closely at a receptacle, one blade is wider - >> neutral, The narrower blade is Hot and the round pin is protective ground. >> Some "equipment" uses only 2 wires. The blades and often one is larger to >> assure that it is polarized correctly. These polarized plugs have come into >> common usage in the last 20 years. Ah. That explains some sockets that I saw when over there last year. > Strange, but common - I don't know any reason why the system has > to be keyed, I always assumed the US development of keyed plugs > was triggered by old DC systems (since in DC Eq. it is necersarry > to know the orientation), but not a new addition. Strange, we > dropped all orientationwhen switching to AC (with Protective > Ground). Could anyone give give a reason why the system has > to be keyed _IF_ a Protective Ground is included (other than > define the Protective Ground pin) ? Because, without Protective > Ground a definition of Neutral is essential, but with, no longer. Because the fuse and/or switch _in the equipment_ has to be on the hot/live side of the supply. Otherwise a blown fuse - because of a short circuit - could leave the equipment with the hot supply still connected to whatever shorted out. Which could be the chassis... Also, at least in the UK, some old equipment had neutral solidly bonded to the chassis and no protective ground. This is common on valved (tubed) radios and things. ISTR that here the fuse was generally on the chassis side, so that when the fuse blew, the chassis would no longer be connected. Still not really safe, since the chassis would be connected to the other side via the heaters of all the valves, and these typically pass 100mA to 300mA at mains voltage, or more if they're cold. Philip.

26 years, 8 months

heads up; OSI Challenger 1P

by CLASSICCMP＠trailing-edge.COM

><>that were clearly under 1.4kw. The codes are aimed at providing reasonabl ><>power. Here a 15A/115v is the nominal and 115V/20A is a max >< ><No, it isn't. I have several 115V 30A circuits in my computer room - ><this being an extremely common rating on the power controllers used ><in smaller DEC systems - and looking at the codes and the Hubbell catalog ><it would seem that 60A circuits are standard things as well. >I should have qualified that as common residential and business circuits. I would call 115V 30A a common business circuit; it's certainly exceedingly common on minicomputer power controllers. What else do folks plug the Twist-N-Locks on their DEC 861C power controllers into? -- 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

26 years, 8 months

heads up; OSI Challenger 1P

by danburrows＠mindspring.com

Be carefull doing this. All foreign 240 mains that I have worked with have been 240 between hot and neutral. This works out to be 416 phase to phase on 3 phase systems. What you will be doing is 240 between 2 hots. This can and will cause problems with a lot of supplies that expect the neutral to be at / near ground. I have several isolation transformers that I use for all the UK equipment I service and they all are wired for 240 Hot to neutral output. Also be careful what electrician you get to set it up for you. I have seen plenty of them manage to wire them wrong. I have even had to explain to them how to wire a buck / boost transformer only to have them fuse it for isolation ratings. >Here's how I'm avoiding this problem for my collection: I'm moving into a >new house and getting 220 installed where my stuff it going to be >located.. since it's right where the breaker panel is, it's not going to >cost much at all... so if the computer in question is going to be located >in a basement or wherever the breaker panel is, you don't even need a >transformer... just get an electrician, friend, or do it yourself.. > >Kevin >

26 years, 8 months

Power connectors

by steverob＠hotoffice.com

> First, to get common names: > Hot = one Phase > Neutral = Protective Ground > Ground = Ground (the starpoint on 3 phases connected to earth at the 'generator') > Hot and Ground are the basic wires to tap power, Wrong... HOT and NEUTRAL provide the power legs. Earth Ground is only for protection and does not carry any power. The power company generates three phase because it is more efficient. However, in most residential areas they only provide a single phase. It doesn't make economic sense for them to string three wires when a single phase will suffice. The single phase (high voltage) is fed into a simple center tapped transformer where it provides 240 VAC for high power appliances and 2-phases each with 120 VAC for lighting and general use. || <---------- 120 VAC (HOT) ----------> || < > || < HV > || <---------- Neutral > || < ----------> || < || <---------- 120 VAC (HOT) In the early days, it was common for manufactures to use the device chassis or frame as a conductor. They would tie the Neutral wire to the chassis (under the assumption that the potential was near 0V) and save a few pennies in the manufacturing process. The problem was, it was possible to put the plug in the socket upside-down. This meant the chassis was tied to the hot leg and you could get electrocution just touching the device. In the 50's and 60's it was quite possible to get shocked by your TV by just turning it on! Today, most devices have polarized plugs so that can't happen. The neutral line should NEVER be fused. If that fuse happened to blow and the one on the HOT(s) leg didn't, the device would still be hot (even with a blown fuse). This would cause an unsafe condition. Steve Robertson - <steverob(a)hotoffice.com>

26 years, 8 months

heads up; OSI Challenger 1P

by danburrows＠mindspring.com

>Tony wrote: >> No. The US mains is 234V centre-tapped. It's not part of a 3-phase system >> (at least not normally) > >Except in the sense that the incoming "single phase" power is derived >from two out of three phases somewhere higher up in the distribution >hierarchy. The utility company doesn't generate different "single phase" >power for residential customers. It is taken from 1 hot (13 to 14KV) of the 3 phase grid. Dan

26 years, 8 months

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test-drb