test-drb April 2003

test-drb@ccmp.vtda.org

272 participants
486 discussions

by ssj152＠charter.net

OK, this may be obvious to the experts here, but I haven't a clue: can a DEC RXV21 RX01 / RX02 floppy controller be used with non-DEC floppy drives, using the standard DEC RT11 driver? By non-DEC I mean ordinary SSSD or SSDD Shugart, Siemens, or Qume 8" floppy drives. I recently saw a project where someone uses a Linux PC to act as a RX02 floppy for a PDP-11 system. That got me thinking: if I can use the RXV21 with foreign floppy drives, I already have a pair of 8" floppy drives that I could use. This would be VERY handy and save me some $$$. OK experts, what is the verdict? Thanks in advance! Stuart Johnson

21 years, 8 months

IF/65 Developement System II

by dwightk.elvey＠amd.com

Hi I'm looking for a users manual for a IF/65 Developement System II by Infotron. It is an ICE box for 6502's. Any information on this would be great. It is designed to be connected to a terminal and a modem. It looks like it can also be run stand-alone. Dwight

21 years, 8 months

HP9885 8" floppy unit

by Innfogra＠aol.com

My 1988 HP catalog indicates that it is the 9127A 5 1/4" floppy that works with the 9000/3XX series of computers. For 3 1/2" drives it is the 9122D/S drive unit that is recommended. There is no mention of an 8" floppy disk drive for use with the 9000/3XX series of computers I don't think the older 9885 floppy disk drive would work unless you wanted to program your own GPIO interface using the 98622A GPIO interface card which should fit in your 3XX. The SCSI/HS HP-IB interface is used as a disk drive interface but not for the 9885 floppys. Paxton Astoria, OR

21 years, 8 months

Apollo Domain, Aegis, etc

by tothwolf＠concentric.net

I just acquired what seems to be a fairly complete set of tapes for an Apollo system running Domain/OS. I was planning to make images of the tapes, and wondered if anyone might be looking for any of this software? Here is a condensed list of the tapes: AEGIS 9.6.1, tapes 1 and 2 AEGIS 9.7, tapes 1 and 2 TCP/IP 3.0 DOMAIN/IX 9.5 NFS 1.0 NFS 2.0 DPCC 3.1 CC 4.8 CC 4.89 CC 6.6 M/6.5 MPX FTN 9.38 FTN 9.66 FTN 10.6 M/10.5 MPX Interleaf 4.0.66, tapes 1 and 2 Some of the (DC600?) tapes have bad drive belts, but that should be pretty simple to correct. -Toth

21 years, 8 months

breathing life into old chips

by julesrichardsonuk＠yahoo.co.uk

> hi, > >> (the chip in question is a ST9293J9B1/AEL for the record, > What is this TV model & brand? It's a Ferguson T7073SJD, using an ICC9 chassis. One website containing a faults database listed the failure of that chip giving the exact symptoms that I see (no sound when the set warms up and the remote operation goes unresponsive). I've pulled the main board and will re-solder all the joints in that area just to check; there's only one electrolytic as part of the circuitry surrounding that chip but I'll replace it with a known-good just in case. Tony's point about the crystal was interesting - I didn't think those things ever failed. I'll see if I've got a spare to try anyway. The set's awful inside - very cheaply made with little thought to cable runs, connectors, and how the various boards plug together. Guess they must have had different teams working on different sections and management for the overall project wasn't exactly what it should have been... (typical of more modern equipment unfortunately!) cheers Jules For a better Internet experience http://www.yahoo.co.uk/btoffer

21 years, 8 months

IBM 5161

by cb＠mythtech.net

>But in the XT, one slot is different. Why? -chris <http://www.mythtech.net>

21 years, 8 months

DF32x4 questions; software needed

by djg＠drs-esg.com

>From: Ethan Dicks <erd_6502(a)yahoo.com> >--- "Dr. Charles E. Morris" <c.morris(a)townsqr.com> wrote: >> registers... Ethan Dicks has pointed out that I should look at the >> drivers in OS8 and TSS8 to see if this will be a compatibility problem. >> http://www.ibiblio.org/pub/academic/computer-science/history/pdp-8/os8/os8.… ftp://ftp.dbit.com/pub/pdp8/tss8 >As I mentioned earlier, I've only done some basic DF32 twiddling >from a PDP-8/i to prove that the interface mostly worked (and to >diagnose my repairs of a smoked rotation sensor board). I've never >had the joy of an 8K machine + DF32s, so I've never had an OS to >explore them. > 4k and 1 DF32 is enough for Disk Monitor System. I built an image with the standard programs and put it at ftp://ftp.pdp8.net/software/dms/ The paper tapes images to build it and the manual are pointed to in the readme. It was installed for 8k since my 8/i is 8k but can be installed for 4k. I also have programs to dump and restore DF32 images over the console port. They aren't online yet since they need a little more cleanup but I can send you a copy. Let me know if you need any help. David Gesswein http://www.pdp8.net/ -- Run an old computer with blinkenlights.

21 years, 8 months

Thanks for the welcome

by tradde＠excite.com

Well, I am mainly into pdp-8 and pdp-11. Those were my first computers when in high school and college. But pdp-10s also interest me. Actually anything pdp related might get my interest. I have a pdp-8e, pdp-11/34a, and a pdp-11/84e. One day I hope to have a pdp-8i as that was the first computer I ever used. I am still working on getting all my systems fully operational. The 8e will have a dual rk05 drive connected to it. The 11/34a will have an RL02. I am not sure what the 11/84 will have as I have only had it a short while. Tim Radde >Well, let me be the frist so say "hello" & welcome aboard! Yes, >you'll >like this place, it can get intresting, some of the discussions get a >little off on a tangent, but aside from that, I've learned a whole >bunch of info I never would have known. _______________________________________________ Join Excite! - http://www.excite.com The most personalized portal on the Web!

21 years, 8 months

Interesting 8/L problem (more than you want to know about switching transistors)

by charlesmorris＠direcway.com

I was sending blocks of data to and from my DF32x4 emulator when I noticed that Bit 5 was always writing a zero to the disk - turned out to be a bad bus driver (M623 in slot D28) and I found a short >from collector to emitter of the output switching transistor. After destroying the transistor removing it, I found out the clamping diode was the actual shorted part :^P so after replacing it with a 1N4148, I grabbed the nearest 2N3904 switching transistor and put it in. Guess what - Bit 5 still didn't work, although it was now changing states! To make a long story short, I found that the rise time of a 2N3904 is reasonably fast (around 50 nS) but the storage time in the circuit DEC used (a 7402 NOR gate driving the transistor base through 390 ohms) is on the order of 500 nS. (Once a bipolar transistor is turned on, there is a significant time required to extract the charges from the base so it will turn off, especially if a negative drive voltage is not available). Although the 7402 output waveform was square, this particular transistor base voltage was dropping much more slowly than any of the others; I could see on the scope that this made the BMB5 output change from 0 to +5 volts AFTER my disk circuit wrote the data into the NVRAM! Some research through the data books showed that a 2N5769, for example, would have been a much better replacement, with a storage time spec of 13 nS. Fortunately, after a little experimenting with "peaking" capacitors across the 390 ohm resistor, an 820 pF gave a sufficiently fast turn-on and turn-off with the 2N3904. So the object lesson here is that all switching transistors are not created equal, even in 1960's technology! Naturally since the DEC part numbers are no longer available, some thought is needed before just deciding on PNP or NPN... -Charles (Relearning long-dormant EE skills!)

21 years, 8 months

New Finds & question

by quapla＠xs4all.nl

Hello all, This morning I picked up some Dec stuff : 1x Alpha 400/166 + 1 Dec storage tower running Unix 1x Alpha 400/166 + 1 Dec storage tower running NT 1 Infotower/infoserver 1000 with 5 CD-Rom's 1 Vax 4000/100 With it came a box of cables, for which I have no idea where they can be used for. One of the cables is marked BC18D-02 and is about 50cm long, the other is a cable which has on one end a sort of high density connector and has a small block in the middle which forks into 4 D25 connectors. The vax 4000 has the female connectors at the back, am I right if these cables are for terminals? Thanks, Ed -- The Wanderer | Politici zijn onbetrouwbaar quapla(a)xs4all.nl | Europarlementariers: zakkenvullers http://www.groenenberg.net | en neuspeuteraars. Unix Lives! M$ Windows is rommel! | Wie mij te na komt zal het weten. '97 TL1000S |

21 years, 8 months

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test-drb April 2003