Seeking recommendations for a good MSDOS/FreeDOS-compatible binary file viewer
(hex / ASCII modes) to stick on my Imagedisk machine...
Technically I don't actually need any editing facilities - just the viewer
side would do.
I think PCTools came with a reasonable one at one point, but there's probably
something better out there that's downloadable...
cheers
Jules
---------------Original Messages:
Date: Thu, 26 Apr 2007 09:45:08 -0700
From: "Chuck Guzis" <cclist at sydex.com>
Subject: Re: DC-600/300XL tape cart observation
On 26 Apr 2007 at 12:16, M H Stein wrote:
>> Aside from the issue of archiving them, is it better to leave them
> until needed, or should I run them through a retension occasionally
> to prevent some of the problems mentioned recently? Any special
> conditions for storage?
>Well, obviously, a lot depends on the tape formulation itself. The
job immediately before this one was a DC-6250 written in 1992. Went
without a hitch. The problem tapes are "Scotch" and were written in
1986-87 and are nothing but problems.
>To me "archiving" is the key. Copy the things off to another storage
medium (say, CD-R) and regenerate copies every few years. It's just
plain foolish to leave things to the mercy of Father Time.
Cheers,
Chuck
---------------Reply:
I'm still curious; assuming any useful data has been archived
and I just want to reuse the tapes some day, what would
maximize the chances of their still being useable? Is heating
them a last-ditch recovery procedure or could it be considered
preventive maintenance? I assume that the 2120s, Travans etc.
are prone to some of the same problems?
Next question:
The DC600s & 615s are Cromemco Cromix+ and UNIX system
and backup tapes; those I have hardware for and they're no great
loss even if they have problems. However, the 300s are for an
Arete/Arix system and I no longer have any hardware that could
read them nor do I know of anyone with an Arix; also, there's the
usual problem that they may have confidential client data on them
along with the system files, so what do I do with them?
I wouldn't mind reusing the tapes but hate to erase them.
Format aside, can a drive meant for DC600s read the lower
coercivity DC300s?
mike
Well, the Univac III is back: UNIVAC III Computer (In Storage since 1975),
eBay auction Item # 2733726990. This time the starting price is $7,500 and the
buy-it-now is $11,000.
The URL is:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2733726990&category=1247
OK, somebody, jump right on it! :-)
(Not me, I'm into LITTLE computers like PDP-11's and VAXen, with an occasional
side dish of 6502 or 8085)
Stuart Johnson
I've had an IMS 5000 system for about a year; I got it off ebay for a
song ($35), but as I didn't know any login name and corresponding
password, it has been a brick. I've thought of a couple ways to break
the security, which isn't all that secure, but didn't due to lack of
time. Finally I made time last night.
The machine specifically is an IMS 5000 IS. It is a very well built
late model S-100 system, aimed at professional applications. This one
came from a dentists office. The main unit contains a 12" CRT, an
intelligent terminal control board (8085 based) which is connected via
an internal serial port to a Z80 CPU card in the main S-100 chassis.
This is a turbodos system, meaning it is a multiprocessing Z80 system.
Serial ports on the back of the machine can connect to remote terminals;
I have one other remote head, also made by IMS.
The machine has a 10MB Rodime hard drive, still working, a single DSDD
floppy (although there is room for another), a master Z80 CPU, a 64KB
parity checked DRAM card, and two MPUs. An MPU is a card containing a
slave Z80 processor with its own 64KB parity checked DRAM and serial
ports, etc.
Although I have the docs showing the gross functionality, I have no
schematics for any of this.
First I rebuilt disk images from Fritz Chwolka's webpage for the IMS
5000, but for whatever reason I couldn't boot these disks. IMS made
more than one configuration of this machine, so it wasn't entirely
unexpected. Next I tried a hardware approach.
The hard disk controller has a 1KB SRAM buffer for holding an inbound or
outbound sector. Programmed IN/OUT transfers fill or drain the buffer,
not DMA. First I verified that the address lines on the RAM were wired
in conventional order by seeing what pins they were wired to on the
74LS193s forming the address counter. The data pin order was more of a
question, but I assumed since the address lines were connected in
consecutive order, so the data pins would be too. I hooked up a logic
analyzer to the RAMs, booted the system, and waited for the password
prompt. I typed some gibberish and hit return, and the logic analyzer
captured the writes to the RAM. I realized the first read or maybe
first few would be reading directory entries to find the USERID.SYS
file, which is a plain text file containing the login names, passwords,
cp/m user area, and privilege level. However, no matter what I did, the
data didn't make sense.
I thought perhaps I messed up the order of the data pins, so I buzzed
out which chip drove the DOn (data out) S100 pins. Again, I did the
login thing, assuming that any time this sector buffer ram was being
read that the data would be appearing on the S100 bus. Apparently not so.
So I switched gears. I shuffled cards around to make space and
connected the logic analyzer to the Z80 and set a trigger for I/O port
operations, triggering on the first IN from the port corresponding to
the sector buffer. Pay dirt. I quickly got the list of users and
passwords, and tried them and they worked.
After disconnecting the logic analyzer, I captured the contents of the
various EPROMs, then called it a night. Bitsavers and Fritz Chwolka
both have interesting web pages, so I won't attempt to duplicate any of
that, but I will be taking some pictures, posting the HEX files for the
EPROMS and making links to the other IMS 5000 resources on the web.
http://groups.yahoo.com/group/symbos8bit/
"SymbOS (SYmbiosis Multitasking Based Operating
System) is a new OS for Z80 based systems and is
currently available for the Amstrad CPC and the MSX2
computers and compatible systems.
SymbOS is based on a micro-kernel-architecture. It
provides real preemptive multitasking, a dynamic
memory-management for up to 576KB Ram, a totaly
Windows-like GUI and support of hard discs with up to
128GB.
This group is dedicated to the SymbOS operating
system. You will get actual information about the
development-progress and can freely discuss about
SymbOS and the supported Z80 computers."
__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
Just curious how, or even if, old design drawings and
such were preserved in the old days. I could barely
venture a guess as to when the first optical recording
drives became "useful", all I remember is a friend
obtaining one of the first (locally) cd players for
his auto in ~the summer of '87. I was in contact with
a few of the people who were involved w/the Mindset
computer, and had hoped I would obtain info on the
custom vlsi chips it used, in any form of course. This
just lead me to ponder when this stuff started
*appearing* on cd's and such.
Can anyone name the different optical CD formats that
modern readers can't work with? I know there must be a few...
__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
>
>Subject: Re: disassembling STacy with a SLEDGEHAMMER.
> From: Cameron Kaiser <spectre at floodgap.com>
> Date: Fri, 27 Apr 2007 22:22:36 -0700 (PDT)
> To: cctalk at classiccmp.org
>
>> > Unless anyone has any other bright ideas, it's going in the trash. It's my
>> > bloody money and I'll get my money's worth out of this piece of crap the
>> > Gallagher way. No wonder Atari burned out.
>>
>> Golly, Cameron--doesn't it say right there on the unit "No user-
>> serviceable components inside"? ;-)
>
>No, it just doesn't say much of anything.
>
>I have never met a machine more impossible to get into for its size.
>
Five gets you 10 there is a hidden screw under a foot or behind a label.
Allison
Hi,
> What is the current status of PDP-11 O/S software? USENET
>seems to indicate that there is no non-commercial license,
>yet the simh website has some of them available for download....
The answers to your question can be found in "comp.sys.dec" and/or
"comp.sys.dec.micro". There was a rather long, heated discussion about this
in one of those newsgroups sometime last year.
Beware of asking your question in those groups though, you'll be opening a
major can of worms....
TTFN - Pete.
Al Kossow wrote:
History San Jose was selling off some of the Perham collection today, mostly
old VTRs and some radio stuff. Got a call that there were two KSR 35s, one
of
which we identified as the console from the SDS 930, and an ASR 33 out
there,
so I drove down to retrieve them. When I got there, the RECOMP was on the
pallet next to one of the 35s. I'm going to try to set up a time to go
through
the computer stuff to try to find the rest, but I'm not hopeful, since I
don't
recall seeing the desk or typewriter.
----------------
Billy writes:
Al,
Congratulations! That is a hell of a find, my friend. I'm immensely
pleased to see at least one of these survived.
In the last box of stuff I loaned you is a thick white binder from
Autonetics. It is the Theory of Operations and Maintenance manual for
several models of the Recomp. One of the early chapters has some details on
the differences between the different models. So you even have some
documentation!
The ones I worked on in the Army all used a Flexowriter for the I/O
typewriter. I'd be surprised if a Model 35 ever worked on a Recomp - too
many years in between them.
There are some details in the book describing early computers that Ed Thelen
scanned and put up on his site. (Some where in the garage is another copy
of that plus an earlier edition, both in great shape.)
Because there is a flat disk for main memory, in the Army we called this the
"Jukebox". There were at least a dozen of these at Redstone Arsenal. They
were used to program the "stable table" of the Redstone missile. I believe
they were also used on some of the early NASA shots that used the Redstone
as a first stage booster.
I'm pleased for you - the Recomp is one of the rarest computers to find in
our hobby.
Billy
