test-drb

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101090 discussions

by a.carlini＠ntlworld.com

I've been trying to read data from some ~2000 era DLT III cartridges that were written on a TZ87. The first one read OK. But the second one failed and it seems that the leader was torn off. I tried a new drive and a second cartridge has failed the same way (the leader was there, now it's not). My immediate problem is that I now have two drives (a TZ88 and a TZ870 that fail POST (all LEDs blink). I guess I need to open them up, fish out the stray leader and fix them up somehow. Does anyone have any experience of doing this? My second problem is that I'd quite like to stop this from happening again. I'm guessing that it happened because the cartridge mechanism was jammed. I've just played around with a TK50-K cartridge and if I jam the two release mechanisms (using the "nose" of two pliers), open the "tape hatch" and gently pull the tape, it moves. Then I can "rewind" it and it's back to the way it was. I'm wondering whether this is safe to do on the DLT III tapes I still want to recover? Is it likely to at least tell me which tapes are likely to fail and which might load properly? My third problem i that I have two cartridges without a leader. Is this something that can be rectified? Thanks for any useful information. Antonio -- Antonio Carlini antonio at acarlini.com

5 years, 7 months

IBM 5160 math copro switch

by jules.richardson99＠gmail.com

Sifting through my XTs and clones... I've had three so far with no math copro (8087) fitted, but switch 2 of SW1 is set to off. IBM docs say off is "math copro installed" and on is the "installed" position, i.e. the reverse of what I'm seeing (the minuszerodegrees site repeats this, although I expect that just copied what's in the manual, too). These three machines (two are 5160's, the other a clone) came from completely different sources - it seems unlikely that all three had 8087's fitted which were pulled at some point. Googling a few more system board images, ones with 8087's have that switch on - but for boards without, the setting seems to be pretty much 50/50. Did the meaning of the switch perhaps change at some point (both of my 5160's are late model 256-640 boards), and rather than being a simple installed / not installed it was more along the lines of "software should use it if present / software should never use it"? After all, it's not like the BIOS will do anything with an 8087; it's only there for software specifically coded to make use of it. I suppose it's also possible that users were in the habit of first setting all the switches to off when configuring a machine, then setting the relevant ones to on according to their memory/floppy/video config - and the copro setting just got overlooked. Weird, anyway. Jules

5 years, 7 months

CGA card (Mitsubishi Electric) with 192K RAM?

by jules.richardson99＠gmail.com

Digging through old PCs, on a battery-removal spree... came across a Sperry 3070 XT-a-like (I wouldn't quite call it a clone, it's a bit goofy) which has a Mitsubishi Electric system board, RAM expansion, and video hardware. The video hardware is... odd. It's actually two full-length boards, joined with a large IDC cable along the top edge as well as via the ISA bus. The only "complex" IC is a 6845 - other than that it's masses of TTL. Output is via a DE9, and pinouts seem consistent with CGA (15.7KHz on pin 8, 60Hz on pin 9, 3/4/5 at TTL levels and 1/2 ground). There's also an RCA jack on the backplate, and that 6845 IC... it all seems very CGA-like, except that total video memory is 192KB. CGA was normally 16KB, I believe. Hercules and EGA 64KB, although I think toward the end of EGA's existence there was a 192KB option. Physical outputs aren't consistent with EGA's two bits per pixel, though. Does this ring any bells with anyone? I don't know why it needs such a large amount of RAM if it's stuck with CGA capabilities. One board is branded WECD10 and the other WECD11, but there's no "model" or anything. cheers Jules

5 years, 7 months

CMU Andrew system (and wm) preservation

by cmhanson＠eschatologist.net

Back before X11 took off, IBM funded CMU's development of Andrew, which had its own complete window system represented by its "wm" window manager. One of the many things that led to X's prevalence was that to get ahold of Andrew and wm, you had to license it from IBM, whereas X was licensed freely by MIT and available via FTP, tape, etc. When I was at CMU in the early through mid 1990s, the CMU Computer Club continued to maintain a fork of "wm" called "wmc" that was available to club members, including source code. While I'm pretty sure I have an archive of this code on a Zip disk somewhere, I thought I'd put out the call to the community to see if anyone else had preserved early Andrew bits since they're both historically important and architecturally interesting. What's architecturally interesting about them? Among other things, CMU created their own shared library mechanism for Andrew, and their own object oriented dialect of C (implemented via a separate preprocessor) that was surprisingly similar to Objective-C. The entire Andrew system was also component-oriented, such that it supported embedding components for handling different media types within each other, while keeping the embedded ones editable -- most of what developers got later with OLE and OpenDoc. So it'd be great if this stuff was archived in such a way that it could be used with contemporary systems, whether emulated or real hardware. Has anyone done any of this yet? -- Chris

5 years, 7 months

Micro Memory VME card info? MM-6316

by cmhanson＠eschatologist.net

I have a Micro Memory Inc. 16MB VME DRAM card MM-6316 but unlike many other Micro Memory products I can?t find a user?s manual. Does anyone know anything about the jumpers/switches for this board? ? Chris Sent from my iPad

5 years, 7 months

domains available (FTGH)

by john＠ziaspace.com

>> Over the years I've snagged a few domains related to classic computing with >> the best intentions of doing something with them. I have not, so I will be >> letting the following expire: >> >> decvax.org >> >> dgeclipse.org >> >> dgnova.org >> >> hp1000.org >> >> hp2000.org >> >> pdp11.org >> >> rt-11.org For anyone here with an interest in any of these domains, I'm happy to offer free hosting for at least as long as I'm alive (working on finding volunteers to take care of things after that). I've hosted some of my accounts and sites since the '90s and can provide email, web, dynamic web, development, gopher, mailman and more. I have real colocated servers, not purchased services, and the servers are, if nothing else, interesting. The collection include an AlphaServer DS25, a Sun Fire v254, an AMD Ryzen box (with ECC), a 1U Amiga 1200, and a 1U VAX. John Klos

5 years, 7 months

Brittle plastic

by technoid6502＠gmail.com

I don't have a way to make plastic new, but I've had good results with WD40 for restoring surfaces with WD40. Some plastics get dusty and highly ablative on the surface with age and environment. Plastic LOVES WD40, if it is 'thirsty' Coat the plastic with WD40, and wait. It will soak in, sometimes it takes an overnight. Repeat this until the plastic no longer 'drinks' the WD40. You've done all you can do now with this method. I don't know that it restores the original strength of plastic, I doubt that, but it sure helps with the surfaces' appearance and wear resistence. Best, Jeff

5 years, 7 months

Brittle plastic

by ccth6600＠gmail.com

Today I was working on a very nice 1995 vintage SPARCstation LX with CDROM and QIC-150 tape drive (3 lunchbox type units). I was trying to install a newer version of NetBSD on it than was already installed. The stack of 3 units was stored in a museum grade glass display cabinet. Sadly all 3 units have a small degree of yellowing but more importantly the plastic cases have become very brittle and bits just break off with minimal mechanical strain. Is there any process to reverse the brittleness which could be used to preserve the cases? Thanks Tom Hunter

5 years, 7 months

domains available (FTGH)

by couryhouse＠aol.com

Please - Would love t he hp2000 domain Jay. Thanks Ed# On Thursday, September 3, 2020 jwest--- via cctalk <jwest at classiccmp.org; cctalk at classiccmp.org> wrote: Over the years I've snagged a few domains related to classic computing with the best intentions of doing something with them. I have not, so I will be letting the following expire: decvax.org dgeclipse.org dgnova.org hp1000.org hp2000.org pdp11.org rt-11.org You can of course wait to get them until they expire via your registrar of choice. If you want them sooner, let me know and after a week or so I'll subjectively decide who to approve a transfer to their registrar. Best, J

5 years, 7 months

domains available (FTGH)

by jwest＠classiccmp.org

Over the years I've snagged a few domains related to classic computing with the best intentions of doing something with them. I have not, so I will be letting the following expire: decvax.org dgeclipse.org dgnova.org hp1000.org hp2000.org pdp11.org rt-11.org You can of course wait to get them until they expire via your registrar of choice. If you want them sooner, let me know and after a week or so I'll subjectively decide who to approve a transfer to their registrar. Best, J

5 years, 7 months

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