test-drb April 2015

test-drb@ccmp.vtda.org

182 participants
220 discussions

Kalok Octagon Seriels Modell 330 Hardisk Service Manual?

by holm＠freibergnet.de

Hi all, Is a SM ior Schematics for an Kalok Octagon Series RLL Harddisks out there? ..don't think that such a thing exists but I would have asked. That are the loud 30MB RLL 3,5" full height Harddisks. I have one that spins up, steps hardly against the internal stopper for a while and spins down again. Lookedwith a scope to the stepper phases and they aren't looking normal at all. The Drivers are 4 IRFR110 driven from 7406's... Would use that disk in a CP/M System with an OMTI5520 Controller. Regards, Holm -- Technik Service u. Handel Tiffe, www.tsht.de, Holm Tiffe, Freiberger Stra?e 42, 09600 Obersch?na, USt-Id: DE253710583 www.tsht.de, info at tsht.de, Fax +49 3731 74200, Mobil: 0172 8790 741

10 years, 1 month

Weekly Classic Computer Trivia Question (20150410)

by dpi＠dustyoldcomputers.com

True or False: The ZFS file system wastes more space on an average file allocation than the ram in a typical PDP-8. At the very least this question might give someone a reason to learn a little bit about ZFS. -- Doug Ingraham PDP-8 SN 1175

10 years, 1 month

Color codes for DEC power supply terminals?

by go＠ao-cs.com

I'm trying to determine if DEC used any standards when choosing colors for the terminal connections on their power supply systems. I have a non DEC 'DECTape' drive I'm in the process of bringing back from the dead and am troubled by the manufacturers use of colors on their terminals. Some make sense: 'black', 'white', 'green' for primary color, although there is a block of 'red' used as an alternate connection to the 'black' (USA: 'hot' leg) of the primary (115VAC) connection. Others include 'blue', 'yellow' and 'orange'. I'm familiar with DEC's use of 'red' for +5, and 'orange' for +15 (or perhaps it was +12) but these do not seem to be the choices here. I've consulted my list of 'small computer handbooks' and 'interfacing' DEC books but haven't found anything useful. Also search google with many many permutations. Any ideas? Perhaps the manufacturer just pulled some out of their hat. Thanks, Gary

10 years, 1 month

VCF SE 3.0 T-shirts

by kylevowen＠gmail.com

The Atlanta Historical Computing Society is selling t-shirts for our show on May 2nd and 3rd. They're available on Kickstarter, but if you would prefer, send me an email and we can work out alternate payment options. https://www.kickstarter.com/projects/20859909/help-fund-the-vintage-compute… Right now, our speakers include Jason Scott, Robert Uiterwyk, Malcolm Macleod, and several podcasts. Our theme this year is celebrating the big birthdays, including the PDP-8, the Altair 8800, and the Amiga 1000. Also, if anyone's interested in exhibiting, let me know. More info about the show at vintage.org. Thanks, Kyle

10 years, 1 month

Color codes for DEC power supply terminals?

by go＠aerodesic.com

I'm trying to determine if DEC used any standards when choosing colors for the power terminal connections on their power supply systems. I have a non DEC 'DECTape' drive I'm in the process of bringing back from the dead and am troubled by the manufacturers use of colors on their terminals. Some make sense: 'black', 'white', 'green' for primary color, although there is a block of 'red' used as an alternate connection to the 'black' (USA: 'hot' leg) of the primary (115VAC) connection. Others include 'blue', 'yellow' and 'orange'. I'm familiar with DEC's use of 'red' for +5, and 'orange' for +15 (or perhaps it was +12) but these do not seem to be the choices here. I've consulted my list of 'small computer handbooks' and 'interfacing' DEC books but haven't found anything useful. Also search google with many many permutations. Any ideas? Perhaps the manufacturer just pulled some out of their hat. Thanks, Gary

10 years, 1 month

Hand-wired core for ROM?

by marvin＠west.net

The PDP16 had a constants card circa 1972 or so. The constants card was basically cores with hand threaded wire done by the customer, and acted like a ROM. I don't remember the capacity, but IIRC it was about 16 bytes. > Did the PDP14 (or any machine of that era) ever use hand-threaded (by the > end user) core boards as ROM? > > tnx. > > g.

10 years, 1 month

Altair Turnkey and some DEC stuff cheap

by jnc＠mercury.lcs.mit.edu

>> On Thu, 9 Apr 2015, Noel Chiappa wrote: >> The real problem is that there's 'grup' (a Dave Clark neologism) in >> the thin space between the plastic contact pin housing blocks and the >> PCB. Needless to say, one can't take the PCB off to get in there... >> >> So my plan of action is to stick them in water for a couple of days, >> and then use a water jet to try and get down in the thin gap between >> the contact blocks and the PCB, to clean it out. Hi, all, thanks for all the suggestions: alas, they won't really help with this part of the problem, since the gap between the PCB and the pin contact housing blocks is only about 1mm (less in some cases) and there's no way I know of to get any kind of effective brush into a gap that small. Maybe something akin to dental floss, but that would be about it. (String might be a good idea, it has a rougher surface and might be better at removing impacted grime, plus it's wider, so will do more width on each pass.) The Simple Green might be something useful to add to the bath, though. I generally use compressed air to dry boards (although I've heard rumours of possible static problems from this, I've never had a problem), which is easy for me since I have a 5HP compressor in the basement. It mostly blows the water (along with any dissolved minerals, although I usually try and finish with a douse of distilled) right off the board. > From: Tothwolf > There /is/ actually a source for replacement gold fingers (and copper > trace material), but that sort of stuff can get expensive if you need > to replace a lot of them. Actually, I wouldn't try and replace the traces; I'd just use wire, and solder the ends onto the remains. (I'm more into functionality than cosmetics. If anyone is really intense about the cosmetics, please let me know, I'd be interesting in hiring you to fix the two boards... :-) The gold contact fingers are another matter, and for them I thank you for your very useful pointer: > You might try contacting http://circuitmedic.com/ and see if they have > any replacement gold fingers the correct width. I have yet to look into this, but I'm sure they'll have something that will serve. The standard DEC contact fingers are 2.2mm wide, but some off-brand boards use fingers as narrow as 1.6mm, so I expect they'll have _something_ I can use. Noel

10 years, 1 month

UK PDP11 wanted

by jnc＠mercury.lcs.mit.edu

> From: Johnny Billquist >> Remember the jumpers I found on the 11/84 backplane? They can turn the >> PMI section (AFAICT) into a real QBUS. > I don't remember any jumpers. http://www.classiccmp.org/pipermail/cctalk/2015-February/003756.html >> For QBUS _memory_, it should 'just work', in the same way that you can >> plug an M8190 into a Q/CD backplane with some QBUS memory, and it will 'just >> work'. (I.e. the M8190 will automatically do QBUS memory cycles if >> that's the kind of memory that's out there.) > I'll believe that when you plug the Qbus memory *before* the CPU in a > Q/CD backplane. But the QBUS part of _any_ QBUS backplane is not 'directional' in the same way the CD part of the backplane in an ordinary Q/CD backplane is. (Note that the 11/84 backplane's CD section is _not_ 'directional' the way a normal Q/CD backplane's CD section is. See: http://www.classiccmp.org/pipermail/cctalk/2015-February/003757.html for more.) So for plain QBUS memory, it doesn't matter where it is in the QBUS backplane, in relation to the CPU. Noel

10 years, 1 month

UK PDP11 wanted

by jnc＠mercury.lcs.mit.edu

> From: Johnny Billquist >> a _system_ with an M8190, a KTJ11 (M8191), and no PMI memory, only >> regular QBUS memory? (Not sure if this will work... but it should, >> I'll try it soon and see. > Should not work, as far as I know. The CPU bus on an 11/84 is always > PMI. We had a prior discussion about this. Remember the jumpers I found on the 11/84 backplane? They can turn the PMI section (AFAICT) into a real QBUS. But that's if one wanted to use a QBUS _device_ in an 11/84 backplane (in the PMI part, of course). For QBUS _memory_, it should 'just work', in the same way that you can plug an M8190 into a Q/CD backplane with some QBUS memory, and it will 'just work'. (I.e. the M8190 will automatically do QBUS memory cycles if that's the kind of memory that's out there.) Now, whether the _KTJ11_ will work properly with QBUS memory instead of PMI - no idea on that one! :-) Noel

10 years, 1 month

UK PDP11 wanted

by jnc＠mercury.lcs.mit.edu

> From: Pete Turnbull > Are you confusing it with a KDJ11-A ... But this is a KDJ11-B Nope. Have several of both (IYWR, it was my looking at my various M8190's that led me to the conclusion that all M8190's, no matter the version, can do PMI). > Basically what makes the difference is whether it's using PMI memory or > QBus memory. ... If you change the config to not use PMI, an 11/83 > becomes an 11/73. After thinking about this for a while, the terminology does now make sense to me, if it's applied to _systems_, not _boards_. An 11/73 is a _system_ with no PMI memory usage (one can of course plug PMI memory into a system with an M8192, but that won't make it use it, i.e. become an 11/83). An 11/83 is a _system_ with PMI memory in use (an M8190, plus PMI memory). But I still think of the _cards_ as either an '11/73 CPU' (M8192) or '11/83-84 CPU' (M8190). The '11-83/84' part does lead to an interesting question: what do we call a _system_ with an M8190, a KTJ11 (M8191), and no PMI memory, only regular QBUS memory? (Not sure if this will work... but it should, I'll try it soon and see. Also, this part is for fun, not serious!) Analogizing to the 73/83 distinction, one might say that it's not an 84, but a '74'... but that number is already taken! :-) Noel

10 years, 1 month

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test-drb April 2015