Are any of the DECUS 12 bit SIG newsletters online? I just found parts
of two of them in my attic (#39 - March 1980 and #40 - Summer-Fall-Winter
1980) and they have some interesting comments about TU-58s and 12-bit
machines.
It's interesting considering the recent activity regarding TU-58s and
emulators. According to (I think) Jim Van Zee, formerly of Laboratory
Data Systems of Seattle), being able to send a break is critical for
reliable operation of a TU-58 (and gives the exact reasons). The M707
and the M8650 cannot do this without modifications (but he does describe
the mod to the M707 and says that it can be done to the KL8E (M8650) but
not the KL8EJ (M8655) or KL8A).
The author goes on to describe a handler he wrote for OS/8 - a non-
system handler. It adds "DTU0" and "DTU1" of 682 OS/8 blocks. He also
writes that it is impossible to write a system handler without an
external circuit or ROM code (a-la 8K TD8E + ROM) to calculate checksums.
His hardware solution is 4 chips grafted onto an M8650 (one of which
is an Intel 8748 microcontroller!)
Additionally, he mentions a virtual TU-58 server written for the VAX
by Jim Gladden, and describes a submission to DECUS of a non-TU58
serial line device handler for the VAX (ASCII files only) that *may*
be submission number 8-921 (my handwritten notes in the margin).
So... if anyone wants to hang a TU-58 (physical or virtual) off of a PDP-8,
we have somewhere to start.
-ethan
> From: acme(a)ao.net
>
> > But, as-is it wouldn't pass FCC regulations.
>
> Not to doubt your word, but what is your source for
> that information? I've had several conversations
> with George Grimm (President of Timex Computer
> Corp.) and he never mentioned a problem with the
> FCC.
I have to say that it was anecdotal and repeated in
every review of the machine I have ever read.
In that day, FCC regs were the big talk about all
sorts of computer equipment.
It was also said that one of the reasons the TRS-80
Model III was created was because the Model I wouldn't
pass FCC regulations as a home computer.
Many PC Clones had problems with the FCC also.
Used to be when you bought a clone you asked:
Does it have an FCC ID?
Does it run Lotus 1-2-3?
Does it run Flight Simulator?
Usually, in that order.
So no, I have no hard data to back that up.
But, the inside of the TS-2068 is shielded and the
Spectrum isn't.
> I would be interested to see photos of the
> prototype. Do you have any Web space you can post
> photos to?
Yes, but they'd be diappointing. Basically, it looks
exactly like a British Spectrum but it has an American
RF converter in it.
No discernable difference on the outside.
> Mind if I ask the company name?
Not at all, it was: Zebra Systems, Inc.
www.zebrasystems.inc
I did most of the tech support, and wrote most of the
manuals and some of the advertising. It was a fun
job...
We did Timex, Coco (I also worked for Specrrum
Projects before coming to Zebra), Amiga and Atari-ST.
Zebra was a sister company to Alpha Products and
Colorware (Tim Jenison of Amiga Video Toaster fame. In
fact, he prototyped the toaster on a Coco.)
Regards,
Al
In a message dated 2/26/03 7:21:26 AM Pacific Standard Time,
rigdonj(a)cfl.rr.com writes:
> Correct, XEROX made a model 8/16 that had two CPUs, one 8 bit and 16 bit. I
> THINK one was a Z-80 and the other was a 8086 but I'm not sure any more. I
> used to have the docs for an 8/16 and I've been looking for one but haven't
> managed to find one yet.
>
>
Xerox made a couple of 8/16s. I have one of the 8086 second CPU boards for my
Xerox 820-II. I was going to install it till a house fire melted the 820.
The original 820 came with dual 8" floppies or an 8" floppy and an 8"
harddrive and ran CPM. It was a spendy little computer for its time. Then
they fit Dual 5 1/4" floppies in an external case, came out with a low
profile keyboard and the add on 8086 Board. They called it the Xerox
820II-8/16.
IIRC the design was taken from the Z80 Big Board which was a popular kit at
the time. It was mounted flat, underneath the CRT and looked much like a
terminal.
At the time the IBM PC came out the Xerox design was hopelessly outdated.
They redesigned the case to a rectangular shape with a separate monitor ala
the IBM PC. They used dual 5 1/2" half height floppies oriented horizontally.
I never saw an actual one but IIRC they used the same Big Board coupled with
the 8086 board that was in the 820 and sold it as the Xerox 8/16.
It ran CPM, CPM-86 and MS-DOS ( IIRC to 2.11). However it was not IBM
Compatible, and did not have IBM graphics.
By the time it was ready the bottom had fallen out of the crossover market. I
don't think Xerox sold any commercially. A liquidation company sold the
remainder for about three years. I doubt they sold many, I bet most were
scrapped for the drives.
The Xerox 820 II was my second computer system and still one of my favorites.
(The first was State Surplus Litton 1251 that I bought for $25.00) I have had
almost all of the various models of the 820 go through my hands over the
years. Besides my original melted one I still have another packed away with
all it's SW. Someday it will run again.
Paxton
Astoria, OR
> From: Patrick Finnegan <pat(a)purdueriots.com>
>
>
> Umm, actually, 'no'. The cable has pins removed to
> change drive selects, and the drives don't have any
> method of setting the drive selects. So,
> swapping the position of the drives changes what
> drive they are. The LED on the front of the drive
> confirms that.
If you're that sure. It sounds like you just have bad
boot disks.
Remember, a Model IV needs a boot disk with the Model
IV ROM file on it or else it won't boot properly. It
will only boot CP/M+ for the Model IV without this.
This *MAY* be why you're having a problem booting
stuff..
> Is there an easy couple line program I could type up
> in basic that using INP() and OUT() to test the
> drive controller to see if it can read from
> the disk? I _could_ read the tech manual I have,
> but I tend to be lazy when it comes to re-inventing
> things that other people already have done.
I don't think so. It might be possible, but I don't
know how to do that.
> One last thing, if it matters... it seems my machine
> was upgraded to 128kB RAM. Is is possible that the
> machine has bad memory that shows up when booting
> from a disk but not when starting up basic?
If the problem is in the first bank, maybe...
I used to use a simple program to test RAM in the old
days...
I think this will work (If I remember it correctly)
10 A = Mem (0)
20 Print A;" ";
30 gosub 10
What happens here is that the program puts the return
for the gosub on the stack and reduces the RAM by a
few bytes each iteration.
If there is bad ram, the computer will crash.
If not, it will eventually end with an out of memory
error.
Contact me off list. Maybe I can somehow make you a
disk you can boot.
I could probably set up my Coco with a Disk Copy
program to copy the disk.
If my Model I were working, I could use SuperUtility
to make you a bootable disk.
I'm looking for a Model III or IV locally to play
with.
Anyone in Philly have one they'd part with?
I'd certainly use it to help Pat out as a start...
I might have something to trade for it you'd want
(like a 56k Modem for a PC or a low capacity PC IDE
Drive?)
Regards,
Al
> From: Patrick Finnegan <pat(a)purdueriots.com>
>
> I recently picked up a TRS-80 model 4, that seems to
> have problems with its floppy drives.
>
<Snipped>
>
> 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.
Ok, a quick primer about TRS-80's and Floppy drives:
Unlike IBM Drives, TRS-80 drives are usually hard
jumpered for specific positions (Not always, but
internal drives are..)
What most people in the PC world don't know is that
floppy drives have an addressing scheme similar to
Master/Slave jumpers on hard drives.
They can be set to positions 0, 1 ,2 or 3. And the
last drive in the chain needs to be terminated (like
SCSI Drives).
For external drives, the drives are set to all
selects, and pins are pulled from the drive cable to
determine what position they are in. If you notice on
IBM Floppy drive cables, there is a twist between the
A: and B: connector. That twist brings the select from
the 0 drive to the 1 select pin. All IBM drives are
set to position 1 (second position).
I don't think a 1.2 mb FDD will work properly on a
TRS-80 Model IV for two reasons. The 1.2mb drive is
much more like an 8in drive than a 5.25in drive. And
transfers data at a higher rate.
Unless the drive can autoswitch to the slower 360k
data rate, it won't work on the controller.
And if you did get it to work, it has a different
Tracks per inch capability than 360k / 180k drives.
However, assuming your problem is with the floppy
drives, and not the diskette you are trying to boot...
A 360k XT Style floppy will work fine, and once you
get it booted, a modern OS like Newdos 80, L-DOS,
MultiDos, etc... Will allow you to use both sides of
the drive for 360k storage.
You can even use 720k 3.5 drives in the same way.
I know for the Model I, LNW made a Disk Doubler Board
that worked with 8in drives, and so would accomodate
1.2mb drives. I don't know if such a disk controller
was ever made for the Model IV.
If you have a PC with 360k Drive, you should be able
to run a TRS-80 Emulator and use a disk image of an OS
to make a bootable floppy in 180k or 360k format.
Let me know if I can help you in any way with this.
The Model I/III/IV was my first machine, and I'm
pretty sure I can remember a lot of info regarding it.
And I still have all my books and disks in my closet.
Regards,
Al Hartman
http://www.geocities.com/alhartman
Join the Macintosh Emulation List...
http://www.topica.com/lists/Macemulist
"It is the soldier, not the reporter who has given us
the freedom of the press. It is the soldier, not the
poet, who has given us the freedom of speech. It is
the soldier, not the campus organizer, who gives us
the freedom to demonstrate. It is the soldier who
salutes the flag, who serves beneath the flag, and
whose coffin is draped by the flag, who allows the
protester to burn the flag."
-Father Dennis Edward O'Brien, Sergeant, USMC
> From: "Fred Cisin (XenoSoft)" <cisin(a)xenosoft.com>
>
> Yep
> The earliest 1.2M drive that I saw (before the AT)
> was a Mitsubishi 4854? I was told that it had had
> been designed for the explicit purpose of replacing
> 8" drives. It did NOT also have a "360K"
> mode.
>
> I also heard a rumor (probably not true) that "When
> Microsoft was writing the DOS and AT BIOS support
> for 1.2M drives, they thought that IBM had
> decided to release a model with 8" drives".
Cool info! Thanks!
> Hmmm. mixing single density sectors and double
> density sectors on the same track?
No, but one could replace the boot sector with the
correct density boot sector when copying the disk to
make it boot on one system or another. It may have
been Vernon Hestor's other OS. V-DOS I think it was
called.
It was a cut-down Multidos he wanted to market to game
manufacturers.
> This'll make your day,...
> I had an LNW. (also a Lobo expansion interface, a
> PMC81, etc.)
I never saw a Lobo Max-80, though I had a few friends
who bought the Mapper board from them to run CP/M on
their Model I's.
> Most of that stuff, I sold cheap at VCF (which is
> run by your buddy Sellam).
He made a comment to me a month or so ago that
indicated he at least KNEW what an LNW-80 was...
Oh well..
An ex-employer (and former LNW Dealer) had several
that he trashed. I found out when I called him to ask
if he would sell or trade any away...
Bummer!!!
Thanks for the cool info!
Regards,
Al
> From: ard(a)p850ug1.demon.co.uk (Tony Duell)
>
> Try re-seating the 'ribbon cable' between the CPU
> board and the disk controller PCB _at both ends_. I
> would estimate that over 50% or disk problems on
> M3s and M4s come from this cable!
You're right about this. It all starts to come back to
me... *Grin!*
This was one of the first things I'd do when a machine
came in with disk controller problems.
I'd also remove the cable totally and clean the
connections with a pencil eraser and possibly some
alcohol.
Mostly, I'd just use the eraser.
Tin to Tin connections would often get oxidation.
Jerry Pournelle used to talk about something called
Stabilant-21 that worked well to keep this from
happening.
This stuff worked great on Model I keyboard to E/I
cables (I soldered on the infamous Gold Plugs on mine.
and made a gold and shielded cable besides) and floppy
cables.
But since the behavior changes when he moves the
drives, it sounds like his "0:" drive is bad.
Regards,
Al Hartman
On Feb 27, 16:50, Megan wrote:
> >I'd remove the CXA16-M serial
> >multiplexers, which I don't think any normal PDP-11 OSs support,
>
> I believe the CXA16s are DHV-like interfaces, RT supports DHVs.
Wel, that would make sense. Easy enough to check by running RT11 with
the correct driver. If so, I stand corrected.
--
Pete Peter Turnbull
Network Manager
University of York
From: Robert Borsuk <rborsuk(a)colourfull.com>
Date: 02/27/2003 10:39 AM
> Woohoo,
> Timex guys on the list. I can ask a Timex (sort of ) question now.
Hmmph. I've been on this list for years :>)
> I have an A&J MicroDrive (Stringy Floppy - The next big thing to rule
> the world) that I don't have any information on. I would love to use
> it with my T1000. It was almost complete in the box. Interface, drive,
> cable, even some new stringy floppies still sealed. Does anyone have a
> manual for this thing? I've poked around online but haven't seen too
> much.
Okay, I have the manual and will be gled to scan it and send it to you.
HOWEVER -- there are some things you should know . . .
First, it will never work with a TS1000 -- only a TS2068.
Second, these things came in two versions -- "A" and "B" -- and the different
versions use physically different tapes, so make sure you have the proper
tapes before wasting any time with it.
Third, these things are the most unreliable form a data storage I have ever
encountered (see the classiccmp thread a couple of years back titled "World's
Crappiest Mass Storage Device" or similar name). Typically, the tapes have
a useable lifespan of less than five hours. Then they break. (This is not
due to my having one faulty drive -- I've owned several and seen more and
they ALL suck!). If you do find a tape that lasts, inevitably the media
goes south (no longer readable) and your data goes with it.
The drives are "cute," and nice for a collector to have, but completely
unreliable.
Later --
Glen
0/0
Hi, I got a call to rescue not too old yet classic equipment. DEC
AXP 3000 and 2600 (?) systems. And some HP9000 K class thing. Plus
StorageWorks RAID stuff. 3 full height cabinets and 3 half height
cabinets, 4-8 monitors and some tape backup boxes. It sounds like
there will be nice stuff among it, yet I am getting into trouble
with my garage space.
I have an MTI StingRay cabinet to kill for making space. This is
a storage system with CI connectors. MTI make. I have taken all
the functional parts out of the cabinet, but the cabinet needs to
go soon. Since I am probably getting blessed with StorageWorks
stuff, I may be have some leftovers. Need to check when I see
the new stuff.
Anyone have a HP9000 K class and runs NetBSD, or one of those
Mach kernel based BSD lite systems? That's what I'd like to
try with the HP9000. It seems quite cute. Although I may part
with it for a VAX 4000-500 or better side-table VAX.
cheers,
-Gunther
--
Gunther Schadow, M.D., Ph.D. gschadow(a)regenstrief.org
Medical Information Scientist Regenstrief Institute for Health Care
Adjunct Assistant Professor Indiana University School of Medicine
tel:1(317)630-7960 http://aurora.regenstrief.org
