I recently picked up a TRS-80 model 4, that seems to have problems with
its floppy drives.
The machine is a base Model 4 with 64KB of ram (I think - haven't yet
taken the EMF shield off the mainboard), and no peripherals attached.
When I powered it up the first time, with or without a disk in the
(bottom) drive, it displayed "Cass?" on the screen, and then I could press
enter to that and the "Memory size?" prompt, and get a basic prompt.
I tried swapping the floppy drives, and that time I got a "Diskette?"
prompt if there was no disk in the drive, and pressing any keys didn't
cause anything to happen. If I put a disk in the drive, the machine never
displays anything, and then after 10-20 seconds, the drive light goes out.
I tried connecting only one drive at a time, with the same results. If I
connected a 1.2MB floppy that I had laying around (a Teac FD-55GFR-149-U),
it did the same thing as if the drives were swapped. Yes, I realize that
the drive probaly wasn't going to work, I just wanted to see if it did
anything.
Also, the disk I used was supposed to be a TRS-DOS (bootable) disk, but
it's possible that they've gone bad after so many years. Are the disks on
the Model 4 recorded so that I can read them on a PC (IE 48/96tpi MFM,
compatible with the NEC D765)? I'd like to know if I can make backup
images and/or see if the disks work on another machine.
Thanks.
Pat
--
Purdue Universtiy ITAP/RCS
Information Technology at Purdue
Research Computing and Storage
http://www-rcd.cc.purdue.edu
--- Ethan Dicks <erd_6502(a)yahoo.com> wrote:
> There is no way any of this will make him see the light about Linux
> or UNIX or anything... he's an HP Customer Engineer on assignment
> with a company laptop and a Digital Personal Alpha Workstation (VMS)
> by his desk (no CD-R drive).
Although I don't think this will help this particular guy, I would
like to say that I have solved the usual "Do I run Windows or {Linux,*BSD}
on my laptop" dilema by running both at the same time under VMware.
I have installed OpenBSD on a separate partition (so that I can boot
native if I have to), but I mostly boot Windows 2000 and run OpenBSD
under VMware. I can then run a Windows-based X-Server (eXceed) and
talk to the OpenBSD, and even use samba (on the OpenBSD) to mount
filesystems from the Windows side. VMware allows direct access to
devices (e.g. CDROM, USB,e tc) which means that I can mount any kind
of CD and access it using Unix tools). OpenBSD can even see the network
so that I can run ssh, IPsec etc from the OpenBSD environment rather than
messing with the Windows equivalents.
(like I said this is general FYI, which may or may not be particularly
applicable to that particular guy).
**vp
When these drives came out, they were touted as being
"as good as a regular floppy drive".
Being 18, and of limited funds... I remember drooling
over the flyers thinking of getting two of these
drives and a bunch of tapes.
My friends in the local TRS-80 Users Group kept
talking me out of that (Kings Byte in Brooklyn).
I guess, in retrospect... I'm glad they did.
I remember that before I went to disk drives on my
E/I, I used to load Level III BASIC (From Microsoft),
which had corrected Cassette loading routines) when I
would type in programs from magazines.
I'm somewhat bummed out that my old Model I is kaput.
I've got a bid on another non-working unit locally in
South NJ, and if I can win that... I'm hoping to
combine the two units into one working one.
My old Model I is like a spaghetti factory inside,
having the following mods:
- Electric Pencil Lowercase Mod
- Dennis Kitsz High Speed Mod (auto switching when
disk drives or cassette are accessed).
- Inverse Video (my friend added this, I hate it!)
- Internal Speaker attached to cassette port (for game
sounds)
- Internal Alpha joystick adapter (just some diodes
and a connector)
- Reset Button
- External Keyboard connector
- Composite Video Out
- Upgraded keyboard with keypad (it didn't have that
originally)
- XRX Mod (for more reliable tape loading
- Gold Plugs
But, the unit is a mess inside.
I'd like to strip out a lot of the junk and see if I
can get it working again.
I've asked my friend who did the mods originally if
he'd do that for me.
Hopefully, the non-working unit I have my eye on is
just a case of loose video RAM chips as the owner said
it worked before he sold it to another buyer, and
after it arrived it booted up with garbage on the
screen.
So, I'm hoping that opening the case and reseating
some chips will fix it.
I did a search and the 21L02 chips (1k x 8) for the
video ram upgrade for Lowercase are still available.
So, I can add the lowercase mod to it. And I can swap
character generator chips with my old unit if need be.
I'm hoping one of my two E/I's is still working so I
can use it with this keyboard unit.
Nostalgia...
As for the A&J units, they worked pretty well when I
used them at Zebra Systems. I used to load the
Terminal program for the 2068 Modem onto one, so I
could load it faster...
I had a few carts tangle (like an 8 track player), but
not many.
It's funny, but in the Dennis Kitsz book he had a
project to modify an 8 track recorder/player to serve
as a mass storage device. The forerunner of Stringy
Floppies and later Tape Drives, I guess....
I leafed through that book yesterday. What fun stuff
there is in there....
I still have the whole series. Especially Disk and
Other Mysteries.. Which was like my Bible back then. I
can't remember how many hosed disks I recovered using
that...
Regards,
Al Hartman
In case anyone is interested, I've posted a scan of the Monrobot XI
Quikomp reference card. This is the language I used to program the
Monrobot XI when I was in junior high school back in the 60's. I'm not
sure if this is the actual machine language of the machine but it is
the only documentation that I have left.
It is on my rather lame web page is at:
http://www.mv.com/ipusers/xlisper/index.html
> --- "Zane H. Healy" <healyzh(a)aracnet.com> wrote:
> > > All I wanted was a way with nothing but Windows to read a VMS
> > > distro disc. I am now firmly convinced that no such thing is
> > > possible without buying *some* piece of software.
> >
> > Did you check http://www.softresint.com/charon-vax/Tools_and_tips.htm
> > like I'd suggested?
>
> I passed the information along to him. He told me that he found a
> reference to a likely utility (makeimage?) but could not find it
> to download. Could that be the magic util?
That bit of info, coupled with Google, turned up the needed info. What you
need is the following Zip file mkimage_vax.zip Unfortuantly it's been
removed from the website. I'll try and find it tonite, hopefully I've still
got a copy.
In the mean time, you might want to check:
http://unxutils.sourceforge.net/ it has a copy of dd.exe that doesn't appear
to need cgywin installed.
Zane
I recently received email from FThomas470(a)aol.com informing me about
the availability of some Monrobot XI computers. I would love to acquire
one of these as the Monrobot XI was the first computer I ever
programmed (in junior high school). Unfortunately, I am not sure I am
going to be able to afford to ship one from Virginia to NH. In any
case, I certainly can't take all 5-6 of them. If you are interested,
please contact the email address above. I don't have any more
information than what I'm posting here. If anyone decides to rent a
truck to move them from Virginia toward New England I'd be interested
contributing to the cost of the rental in exchange for hauling one for
myself.
Here is the text of the messages I've received about these machines:
Litton Industries's Monrobot XI
We are in Charlottesville, Virginia and we have 5 or 6 of them in
storage. Until 7 or 8 years ago two of them were still being used and
worked just fine. In their time, they were really great machines and I
enjoyed programming and working with them.
We also have 2 Friden Computypers which are earlier than the Monrobots.
They had no electronics at all, but used rwo Friden late model
mechanical calculators with solenoids on all the keys and electrical
contacts on all the dials. They used a pile of stepping switches and a
big plug-board for programming. It was a far-out design but worked very
well.
We will be moving shortly and are pressed for space. Please let me have
your thoughts and/or suggestions. If you are interested, any reasonable
offer would be considered.
The Monrobot consists of the main computer unit which contains the
electronics and magnetic drum, a little control unit with switches and
control buttons and a place for the I/O typewriter. It's about the size
of an office desk and weighs about 400 lbs. A side section connects to
it and has a paper tape punch and a reader.
Robert Nansel wrote:
> I came across reference to a file, LAMP.ZIP, you posted briefly for the
> Classic Computer list back in '99. Would it be possible for me to get this
> file? I'm fascinated by the idea of making counters, logic gates, and
> memory elements using neon lamps, but repeated google searches reveal very,
> very little hard information (other than there were such circuits).
I have put lamp.zip back up on my web page
once again. The zip file contains scanned
images of pages describing glow lamp logic
circuits. The size is 1.6 MB.
http://dcoward.best.vwh.net/lamp.zip
These scans are from "General Electric Glow Lamp Manual",
first edition, 1963 pages 45-66
I would appreciate someone hosting these scans
because I don't have the space to keep it up there
all the time.
--Doug
=========================================
Doug Coward
@ home in Poulsbo, WA
Analog Computer Online Museum and History Center
http://dcoward.best.vwh.net/analog
=========================================
>What's happened in the intervening two years - filled the
>gaps with more machines ? :-)
Well, although I've acquired a few additional machines (and
manuals, handbooks, software and other memorabilia), the
condo is getting pretty empty of such stuff as I try
(seemingly perpetually) to prepare it for sale... the
machines are in storage (with a few machines being held for
me at other locations)
Someday I hope to have a house with a basement and garage where
I can truly have the stuff available to be seen...
Megan
