test-drb February 2002

test-drb@ccmp.vtda.org

293 participants
1043 discussions

Fwd: Re: OT: cleaning pots on my vintage audio amp

by erd_6502＠yahoo.com

--- Pete Turnbull <pete(a)dunnington.u-net.com> wrote: > "iso-propyl alcohol" is the "old" name for it; "iso-propanol" is a more > modern version of the same name; Agreed. > the "systematic" name (used almost everywhere *by chemists*) > is "propan-2-ol"... Since it's been years since I've been in a chem lab... when did this naming convention hit the States? In 1985, I'm fairly certain we called it isopropanol. Perhaps my education was behind the times. > > Even "aluminum" is different, but I don't remember how different... > > You mean "aluminium" :-) Like sodium, potassium, uranium, ... Platinium... err, wait... nevermind. ;-) -ethan __________________________________________________ Do You Yahoo!? Yahoo! Greetings - Send FREE e-cards for every occasion! http://greetings.yahoo.com

24 years

SCSI options for PDP 11/23

by pete＠dunnington.u-net.com

On Feb 27, 20:49, Zane H. Healy wrote: > OK, what I see that concerns me is the fact you're using a 11/03 box. > Unless I'm mistaken the 11/03 was only Q16, which has me wondering how > you're even running a 11/23 CPU, which should be Q18, in it (it's possible > someone upgraded the backplane to be 18-bit). An 11/03 backplane is already 18-bit. BDAL16 and BDAL17 are bussed so it can use parity memory. It's also easy to upgrade to 22-bit, by soldering wrirewrap wire onto the extra 4 lines, though any 11/23 or 11/23+ will work fine (as an 18-bit system) without doing that. I can't think of anything that will fail to work on such a system, apart from software that needs more than 124KW of memory, obviously. Specifically, I/O page access will work coreectly for any properly designed device, and RT-11, RSX-11, etc will just see it as a normal 18-bit system. Oh, and an 11/23 would work fine on a 16-bit backplane, unless you wanted to use parity memory. The MMU wouldn't be useful (you could take it out, though you don't have to; an 11/23 will work fine with 28KW and no MMU chip). -- Pete Peter Turnbull Network Manager University of York

24 years

DSSI support for NetBSD: request for docs.

by jkunz＠unixag-kl.fh-kl.de

Hi. Now that my RX01/02 driver for NetBSD and the accompanying "NetBSD device driver writing HOWTO" is nearly finished, I am looking forward for further challenges. I think will stay in the disk (and tape) department and write support for DSSI. I know that this is not a trivial task, but I will give it a serious try. So I have the usual problem: docs. I need docs about DSSI, the protocols that are used on it, the host adapter chips (SII and SHAC), MSCP, SCS, ... The KA6[46789]0 CPU and KDA50 / UDA50 programmers manuals should be a good start. So if this docs are online somwhere on the net, please give me a link. Thanks for your help. -- tsch??, Jochen Homepage: http://www.unixag-kl.fh-kl.de/~jkunz/

24 years

PDP-10 Emulators (was Re: Alpha AXP (was Re: MicroVAX 4000/VL C))

by dhquebbeman＠theestopinalgroup.com

> [TOPS-20...] > > Well, I'd like to run a TOPS-10 instead, seeing as there are already two > perfectly good TOPS-20 machines (Toad and XKLeTen) on the net, but TOPS-10 > does not support TCP/IP, and therefore won't run multi-user under KLH10. SIMH can do this now with a bogus DZ11 implementation, similar to what you were previously doing with Tim Stark's emulator... -dq

24 years

NEC applications processor

by rdd＠rddavis.org

Having what appears to be some sort of "applications processor" made by NEC, model 3401, class 5451, as well as another box labeled "class H6830-STD1-01-46," and not being able to obtain any information or documentation about this equipment, I'm not quite sure what do with them other than take them apart for parts. On the 3401, there are three ports labeled "LS Link," four labeled "HS Link," two labeled "System Bus" (channel A and channel B) and a diagnostics port. If anyone has a need for these boxes, or can provide me with any information about using them, then I'll consider not taking them apart, as tempting as that option is, considering that: they're taking up a fair amount of space, and have some useful ICs, wire, fans, PSUs, LEDs, memory, etc. inside, and the one case could be modified to hold several 5-1/4" hard drives and the PSU. I'd really like to find a way to use this equipment in it's present assembled form, however. :-) -- Copyright (C) 2001 R. D. Davis The difference between humans & other animals: All Rights Reserved an unnatural belief that we're above Nature & rdd(a)rddavis.org 410-744-4900 her other creatures, using dogma to justify such http://www.rddavis.org beliefs and to justify much human cruelty.

24 years

RX02 / DSD440 problem

by pete＠dunnington.u-net.com

On Feb 27, 10:48, Tom Leffingwell wrote: > It does look like it wants to go back to track zero. If I manually line > it up just right, it will power up correctly, but as soon as it wants to > go somewhere, the problem starts over. Meanwhile, the other drive lines > itself up just fine. Then it's possible that the drive to the stepper motor that turns the leadscrew is, er, screwed. It might only be one phase; if you can turn it easily by hand when it's powered up, then it's probably not being driven at all so look for a destroyed driver or lack of 12V (or is it 24V? ). If it tends to settle into certain positions and won't step but does sort of vibrate and isn't very easy to turn by hand when the power is on, it's probably just one phase; look for a blown driver transistor (if the drive has such) or a faulty stepper driver IC. It's also possible (though unlikely, in my experience) that one of the coils in the motor has burnt out. You can check that with an ohmmeter, comparing it to the working one. -- Pete Peter Turnbull Network Manager University of York

24 years

Multiple floppies in one system?

by pete＠dunnington.u-net.com

On Feb 27, 17:23, Russ Blakeman wrote: > Well SOB - they still sell the MCT 8 bit 4 floppy controller - about 1/5th > of what it used to cost in 85...here's a link to it: > > http://www.jdr.com/interact/item.asp?itemno=MCT-FDC-HD4 Interesting. Anyone know if it supports single density, and/or works with 8" drives (in conjunction with suitable cable adaptor)? -- Pete Peter Turnbull Network Manager University of York

24 years

RX02 / DSD440 problem

by pete＠dunnington.u-net.com

On Feb 27, 12:21, Andreas Freiherr wrote: > Darn! - I disassembled the whole stuff manually yesterday evening! :-) I apologise for the slightly non-standard syntax used, notably for octal constants; it was rewritten for (and then assembled by) a home-grown cross-assembler. > Non-obvious is that only two sectors (1 and 3) need to be read: the code > in the manual continues up to sector 7 (constant in word 2124, or in > your copy, at 1124), in steps of 2 (BTW, why are even sectors skipped?). I think there were actually three errors in my original copy. Anyway, the version on my website is now correct. It's not the only way to do it, I've seen other versions (there are similar versions, not identical, but interestingly enough with mostly the same errors, in various RT-11 manuals, the Microcomputer Peripherals Handbook, and the RX02 Pocket Service Guide). The reason for the number of sectors is that you can use the same bootstrap with trivial alterations for a single-density boot, but then you need four. sectors, not two. The reason for missing the even-numbered sectors is because they are software interleaved to give time for the memory transfers between reads. > The most non-obvious error is using the word at location 1132 either as > a HALT instruction (when aborting bootstrap due to an error detected by > one of the BMIs) or as a constant to load into R0 (when finishing > bootstrap and passing control to address zero, for which a CLR PC is an > excellent JMP @#0 replacement). My copy of the LSI-11 manual had this > completely wrong - it would fail to abort properly. Some versions actually have the HALT elsewhere. I once spent ages trying to work out the shortest variation on this bootstrap, IIRC I managed to save just one word. > Starting the bootstrap might be easiest with a 1000G (or in the original > copy, 2000G). one command shorter than setting R7 to 1000 and then > <P>roceeding. The reason for the <P> instead of <G> is to avoid a bus reset, which makes the RX02 and some processors "do things". And you're supposed to disable interrupts by setting a mask in RS first. It doesn't use the stack, though, and any decent second-stage boot should set R6, so I suspect that's redundant. I'm surprised your version starts at 2000. By convention, all normal bootstraps and similar start at 1000 -- the best-known exceptions being XXDP code (starts at 200, same as on a PDP-8) and the TS11 bootstrap which starts at 10000 (to allow space for larger tape blocks). -- Pete Peter Turnbull Network Manager University of York

24 years

RX02 / DSD440 problem

by pete＠dunnington.u-net.com

On Feb 26, 13:41, Tom Leffingwell wrote: > > The first message I normally see is RT-11 loading...I never have to do > anything, it just boots from DY0:. If I don't have a disk in, or its > messed up for whatever reason, I get: > > 173326 > @ > > I looked a little closer inside the unit, and it doesn't seem to have a > belt. There's a worm actuator that shakes when on power up when it tries > to move back to its starting place. It can be moved by hand easily, so > it doesn't seem to be binding. That's the head positioner leadscrew. On powerup or a Bus Init, it should move back to track zero (maybe only if there's a disk in ithe drive, depending on the controller). The drive belt is on the underside of the drive. They often fall off. A quick way to test if the drive is turning, is to take a floppy, trun the disk in the jacket until the sector hole is visible in the round hoe in the jacket, put it in the drive, close the door, open the door, take the disk out, and see if the sector hole is still visible. Most 8" drives rotate all the time, so closing the door (which clamps the disk to the spindle) should turn it. The odds of the sector hole ending up in exactly the same place after this are minimal. It doesn't tell you if the drive is running at the correct speed, but it will tell you if it's not turning at all. If not, the most common causes are that the drive belt has slipped off the pulley, or that the plastic collet which clamps the disk has broken and isn't clamping, or not well enough. -- Pete Peter Turnbull Network Manager University of York

24 years

PDP-10 Emulators (was Re: Alpha AXP (was Re: MicroVAX 4000/VLC))

by healyzh＠aracnet.com

> Until I have a pressing need for 64 bits, I will probably keep this > box at a low priority, but if any of the PDP-10 emulators would > rather be on a medium to slow-speed 64-bit machine rather than on a > medium to fast 32-bit machine, I might dust it off. I just don't see > where it's anything besides cool for the sake of cool right now. I've not tried running KLH10 on the AlphaStation 200 4/233 running OpenBSD I have, but I've run the PDP-10 version of SIMH on it. You really don't want to do that. It was usable, BUT it was *CONSIDERABLY* slower than a KS10. I've got a 500Mhz Celeron w/256MB RAM, and a 8MB HD plugged into a bare MicroATX i810 board sitting on a shelf. It makes a killer PDP-10, and can run two copies of SIMH (TOPS-10 7.03 and TOPS-20 4.1) at or faster than KS10 speeds. Of course what I really like is the 1Ghz PIII running KLH10 running TOPS-20 V7.0, especially since I can telnet directly into it :^) Zane PS anyone looking for information on emulating DEC systems should see: http://www.aracnet.com/~healyzh/decemu.html especially for PDP-10 emulation.

24 years

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test-drb February 2002