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
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
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
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
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
>> 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
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
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
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.orgdgeclipse.orgdgnova.orghp1000.orghp2000.orgpdp11.orgrt-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
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.orgdgeclipse.orgdgnova.orghp1000.orghp2000.orgpdp11.orgrt-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
