>
>Subject: Re: Tarbell is making me insane
> From: Grant Stockly <grant at stockly.com>
> Date: Mon, 12 Nov 2007 00:43:21 -0900
> To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org>
>
>Allison, thanks a lot for the detailed response! A lot of that info
>can be used to help other people too!
>
>I've written this e-mail from the "bottom up", so some things may
>seem out of order in the time line.
>
>I think that I'm to the point where I've narrowed the problem down to
>inside the tarbell card, but I don't think the problem is the
>1771. Any further hints are well appreciated. : )
I've seen bad 1771s out of the box (WD was not allways a qualaity house)
but I've never seeen one fail in service excluding overvoltage or reverse
polairty.
One little nasty. The 1771 has a basic ability to do data seperation.
I havent' looked at a tarbel board in a very long time but I do hope
that they didn't do the TRS80 save a buck trick and try to use that
internal seperator, it does NOT work. It has zero jitter tolerence.
>I think we're getting closer!
>
>> >I can't speak for the exact combination of the Tarbell, but the
>> >system has been running all day long with:
>> >-16k static card
>> >-8k static card
>> >-4k static card
>
>The disks are 24k CP/M 1.4, the 4k is for the monitor. Forgot to say
>that... Included on my source disk (which is read by the flaky
>tarbell) is a BIOS for 48k CP/M, but I have never had it going long
>enough to patch, movcpm, or whatever it is that has to be done to get
>the new CP/M onto the disk...
Just making sure.
>>Ok you have 28k ram. Is the image sized and booting in that?
>>If the image is sized for say 32 or 48K it will crash, likely
>>as a bounce back to rom monitor.
>
>See previous response for a description. When it runs, it
>runs. When it doesn't...it doesn't : (
The fact that it runs is good. You have a viable image but a systemic
problem.
>I spent all day long writing my own tarbell driver / monitor program
>that would select, reset, seek, read, write, etc. When I tried the
>read monitor command for the first time I didn't get an error. I
>tried booting CP/M and it worked... Then I swapped to the more
>troublesome tarbell card to get errors (I know, stupid) The problem
>appears to be within the tarbell card. I can reliably get my tarbell
>monitor to report this:
>
>Reading A Sector
>ERROR: Record Not Found!
>"
Data is comming from the disk, however it's not readable. Possible
reasons:
NOISE, ground the drive, insure it has good power that the
system case and it's grounds are common. Also common
error is long drive cables (stay short for now) and cables
(and drives) that get near CRTs.
Jitter:
EXTERNAL: This can come from noise as above. Also drive
mechanical issues.
Internal: 1771 requires a data seperator to recover clock and
nice(cleaned up some) read data. The common circuits
are oneshots and PLLs. Tarbel used oneshots. Generally
they work well enough if set right.
LOGIC: problem with read/wait hardware not working or possible
data path corruption.
>
>When I swap to the "better" tarbell, the basic sector read command
>passes. (BTW, the reliably bad one above did boot CP/M once and gave
>me a few good sectors!!! And I've swapped the 1771 between boards
>and the bad stays bad and good stays good!) Basically I use the
>monitor to clean the memory, load my program, and then I flip the
>reset switch on the Altair. The Altair runs my program which starts
>at 0000 and then jumps back into the rom monitor. Here is the
>tarbell being good:
your shotgunning. I've seen this for 30+ years. Doesn't work, swap
out the big hairy chip as they must be flaky or why else put it in a
socket? Rare if ever is that the case.
FYI: certain brands of sockets of the side wipe style tend to fatigue
with insertion/removeal and some do it over time leading to failures
where the chips are 100% good but nothing works and may be flakey
if wiggled or moved.
>"
>MON85 Version 1.1
>
>Copyright 1979-2006 Dave Dunfield
>All rights reserved.
>
> > F0000 3000 00
> > L
> >
>
>Reading A Sector
>
>MON85 Version 1.1
>
>Copyright 1979-2006 Dave Dunfield
>All rights reserved.
>
> > m2000
>2000 1E 0A 31 00 01 21 00 45 16 33 0E 02 06 04 79 CD ..1..!.E.3....y.
>2010 2A 00 15 CA 00 5A 06 00 0C 79 FE 13 DA 0F 00 3E *....Z...y.....>
>2020 53 D3 F8 DB FC 0E 01 C3 0C 00 D3 FA CD 41 00 3E S............A.>
>2030 88 B0 D3 F8 DB FC B7 F2 41 00 DB FB 77 23 C3 34 ........A...w#.4
>2040 00 DB F8 E6 9D C8 1D C2 02 00 32 80 00 2F D3 FF ..........2../..
>2050 C3 50 00 00 5A 80 04 19 00 02 00 45 80 04 15 01 .P..Z......E....
>2060 01 80 51 00 00 00 00 00 00 00 00 00 00 00 00 00 ..Q.............
>2070 00 00 00 00 00 00 00 00 00 00 00 00 00 C3 00 00 ................
>"
>
>I have to pull the card out to enable the boot rom...guess what, it
>boots...but at the moment it is only reading "real" DD media. The HD
>media with the tape "works" but BDOS complains about "bad
>sectors". This HD disk on another day works just fine.
DD or HD with tarbel??????
>I ran one of the programs:
>"A>disktest
>
>TARBELL MINI-FLOPPY DIAGNOSTIC OF 8-1-80
>STANDARD VERSION 1.8
>40 TRACKS 18 SECTORS
>
>SELECT DRIVE. (A/B/C/D) a
>HOW MANY RETRYS? (0-9) 4
>SELECT STEP RATE. (S=40MS,M=20MS,F=12MS) m
>FULL TRACK SEEK? (Y/N) y
>TO START TEST TYPE RETURN.
>
>0 READ ERRORS DETECTED.
>
>REPEAT TEST? (Y/N)
>"
>
>Maybe that gives you a clue as to what I'm working with.
>
>And if I try my HD disks it does this: (to every sector on every track)
>"
>READ RECORD NOT FOUND ERROR.
>TRACK 0 SECTOR 1
>
>READ RECORD NOT FOUND ERROR.
>TRACK 0 SECTOR 2
>
>READ RECORD NOT FOUND ERROR.
>TRACK 0 SECTOR 3
>"
>Last weekend that was my boot disk and I had several basic programs
>compiled with basic-e on it.
HD media is incompatable in every way with older drives and lower
data rates.
Drives used for HD media are 96tpi and track pasing ansd width are
different, incompatability is oftenn the case or at best it gets by.
Don't have Tarbell schematics handy to check.
Does the read loop test a status bit or hang/wait on read?
If it's hang wait on read is that also tied to interrupt??
If it's read a status bit two things:
CPU MUST complete the read a byte loop in 32us (64 for mini floppy)
and CPU speed makes this in some cases difficult.
can you supply the sector read code? ( should be fairly short)
>>Is the boot image set up for MITS 2SIO and does it set it up?
>
>I have a session captured from "once upon a time" when it booted
>(which is more random than anything I can think of)
>
>"TARBELL 24K CPM V1.4 OF 7-20-79
>2SIO MINIFLOPPY VERSION.
>HOW MANY DISKS? 2
>A>dir
>A: CPM COM
>A: SYSGEN COM
>A: DDT COM
>A: COPY COM
>A: PIP COM
>A: ASM COM
>A: STAT COM
>A: ED COM
>A: FORMAT COM
>A: DISKTEST COM
>A: DUMPDSK COM
>A: BASIC COM
>A: RUN COM
>A>
>"
Yeeha!
>>I assume thse are in high memory and not below the address the image will
>>try to boot to. CP/M wants from 0000h to system size as configured.
>
>My bytesaver is at C000 and 4k of sram for the monitor is at
>E000. There is 24k of contigous memory at 0000.
>
>>Doesnt assure the FDC is set right for the drive and media.
>>Also doesnt assure the media is SD or even bootable.
>>Further is the media is not using a 2sio as the IO the system could
>>boot and crash or appear to.
>
>The drive, tarbell, and boot disks were mailed to me from a fellow
>enthusiast. He made all of the modifications, made the disks,
>etc. He has tested the setup in an IMSAI (kind of) with my (kit)
>CPU, a SSM 8080, and a ZPU at 2MHz.
Kind of and exactly are differnt things.
>To add to that, I have myself booted off the setup, formatted disks,
>made copies, ran the basic compilier, ran asm, etc. But something
>(and I think its IN??? the tarbell card does not like me, Alaska, my
>Altiar... I don't know! : (
Could be an interaction of both.
>
>A quote:
>"My Imsai has a standard front panel with a factory suggested mod. to
>do a power-on halt at zero. It has two 16K Industrial Microsystems
>static ram boards, a SIO2 serial board and a SSM 8080 CPU. The prom
>on the Tarbell is turned off to let the front panel operate properly
>at power on. The Tarbell is then booted by using a MITS eprom board
>and the 1702A eprom you burned for me. The power supply is a
>Industrial Microsystems switching supply which powers both the drives
>and the backplane
But you don't have "that". You sorta have something like that.
>Following is the different configurations I have used in the test
>unit to boot the Tarbell;
> 1. With a Z80 Cromemco ZPU set at 2Mhz, power-on jump set to
>zero and no front panel. The Tarbell boots at power-on and will do a
>cold boot every time you push the reset button.
> 2. With a ZPU and Imsai front panel the Tarbell boots
>only when the run switch is pushed.
>
> 3. With the Altair CPU and no front panel the Tarbell will not
>boot at power on or after a reset!
No suprize, the MITS CPU has no POJ, nada. It must be reset, load address
and then run.
> 4. With the Altair CPU and the Imsai front panel the Tarbell
>will boot after you push reset and then push the run switch.
Says the MITS FP is causing some pain.
>
>After the Tarbell boards boot I have never had a problem or dropout
>in CP/M with any CPU- front panel configuration. The static ram
>boards use low power chips and run cool.
thats good but getting there is an issue.
>Remember my Altair CPU board uses a 8224 in the oscillator circuit
>and I replaced the 8T97 with 74LS367's.
>"
The 8t97s worked fine for me. It has 8224? your mod or 8800B?
>This is some info on the mod:
>"The modification we have on our Tarbell boards was designed for the
>5.25 Tandon TM-100 single sided. single density 48tpi drive which was
>one of the first 5.25 drives produced. It might be that some of the
>new 3.5 drives just won't work with the setup we are using."
The only media that should go in that drive is the brown SD/DD floppies.
If the media was written on a 96tpi drive the noise and jitter _will_
be higher due to track width differences. IF the FDC oneshots are
not quite on that makes a huge differnence.
The hub clamps sometimes off center the media and still media will
sometimes drag the motor speed down. Watch for that.
>>Could even be a simple bad IDC crimp on the cable.
>
>I have tried a few FDC cables. Maybe I should make a new one.
Suggestions of the obvious.
>
>Time for bed. : (
>
>Grant
Don't know if it helps
Allison
Didn't that "Superbrain" computer use a couple of Z80 chips in there? IIRC,
one was the "main" CPU and the other one handled I/O tasks of some sort
(disk?). I had a guy come into my shop one time wanting a couple of those
fixed, but I could find *no* data on them at the time and therefore couldn't
do too much for him...
Are there docs out there for this beast? I'm just wondering how they divided
things up between the two CPU chips, and how they interfaced things...
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin
>
>Subject: Re: Tarbell is making me insane
> From: Grant Stockly <grant at stockly.com>
> Date: Tue, 13 Nov 2007 22:57:55 -0900
> To: "General Discussion: On-Topic Posts Only" <cctech at classiccmp.org>
>
>
>>FYI: 3.5" disks were never meant to run at 125khz. The
>>720k mode is 250khz and the 1.44mh is 500khz. The read
>>amps just may not work well down that low.
>
>Do you think that it would be better if I were to get the Tarbell to
>run at 4MHz (250kHz)?
>
>I'd have to make a new BIOS and modify the format program. I don't
>have source for the format program. Does anyone off hand know where
>source to the Tarbell CP/M utilites could be found?
Or utilities for any FDC based on 1771 could be modified.
>I should be able to format the disk as 36 sectors 80 tracks and
>possibly configure it to use both sides. That would be formatting it
>to capacity...
>
>I'm going to write a disk image tool that dumps the disk to my
>computer. I could write one that also writes an image to a disk.
>
>What do you think would happen if I were to try to use the disk at
>250kHz but only put half of the sectors? Will the 1771 handle the
>extra time or give me errors?
Take the time to read up on 1771 and FDC formats before you just
plunge in. You will arrive at a better solution and spare yourself
wasted time.
Not all 1771s where shipped as full speed parts too.
>This faster signal might be better for the disk drive?
Potentially. Remember FM floppy recording was passe' by the early
80s with every one needed far greater space. It want even a
consideration buy time PC 3.5" floppies hit the street.
>It may seem strange I'm fighting with this so hard, especially since
>I'm working on Altair disk drive system emulator using SD cards, but
>nothing beats real live hardware. : )
I can understand wanting a floppy, a real floppy. However I'd expect
a goal such as being able to read 8" SSSD (cp/m standard) or other
widely used format for archival or transfer.
Another controller that ended up in altairs very often was the NS* MDS.
It's hard sector but there is a lots of media and programs for it's
DOS and also CP/M. Getting floppies is a pain however.
Allison
>Grant
Nice article up on the BBC news website about the Cipher Challenge that's
going on today:
http://news.bbc.co.uk/1/hi/technology/7094881.stm
... I've not been involved in that side of things, but it's been interesting
watching Tony and his crew running around the last few weeks trying to get
everything put together (there was a huge amount to do on the
reception/intercept side of things in particular)
cheers
Jules
I have a Bally Computer System,Astrovision Arcade Model ABA-1000-2. 7-controllers,1-video touch pad,11-games,2-Arcadian Cassettes,1-TV adaptor,2-key pad over lays,1-Bally Basic Computer Programming Cartridge With Built-In Audio Interface,and a complete set of manuals.
----------Original Message:
Date: Thu, 15 Nov 2007 21:32:19 +1300
From: Ethan Dicks <ethan.dicks at usap.gov>
Subject: Intellegent peripherals (was Re: MIT provides MULTICS source
and documentation (DPS-8 simulation))
<snip>
The DOS for the 2040/3040/4040/8050/8250 drives had a "copy drive N to drive
M" command (I'd quote chapter and verse, but I don't have access to the 'net
right now).
<snip>
You could then, say, use your IEEE-488 acoustic coupler to logon to a BBS
while disks were copying, or print to a printer, or whatever, since the IEEE
bus was not involved in that disk-to-disk copy.
<snip>
-ethan
---------Reply:
And if there was an error during the copy or backup the drive merely lit an
error LED (which some people supplemented with a piezo beeper because
it was easy to miss) and you had to ask the drive what the error was (and
clear the error condition). That way whatever you were doing in the meantime
would not be interrupted with an error message.
You could also defragment (collect) the disk while doing something else,
although for some reason the format (header) command tied up the computer
until it finished.
m
At 10:40 AM 11/15/2007, you wrote:
>As part of the process of getting a second C128 system set up and
>running, I recently ordered another Commodore 1084 monitor from an
>eBay seller. The one I have is nice and bright and lets me switch
>quickly between the composite (40-column) and RGBI (80-column) outputs
>of the 128, so I was happy to stumble across another one for a
>reasonable price.
>
>It arrived last night, and it's a great little monitor, in even better
>shape than the one I already had. To my surprise, though, it's also
>completely different. The case is different, the form factor and
>positioning of the controls are different -- and, most relevantly,
>even the connectors are different. My older one (made in 1989) has a
>DB-9 input for RGBI input. The new arrival (made in 1988, if I recall
>correctly) has an 8-pin DIN input for RGBI input.
>
>Thankfully, I already had a DB-9 to DIN-8 cable in the Big Box of CBM
>Scraps, so I didn't have to order any cable-making parts from Mouser,
>but it does bring up a question: how many potentially problematic
>variations on the same model number did Commodore make? I know that
>they did a lot of this sort of thing, given the ever-changing
>appearance of the C2N and 1541, but is there a quick and easy question
>I can ask a seller to find out exactly what ports to expect on the
>back of a 1084 (or similar monitor)? "DB-9" and "8-pin DIN" are
>already way too difficult to explain to somebody just trying to clean
>out their attack, but if there's a guide out there with a breakdown by
>manufacturing date or serial number for some of this Commodore
>equipment, that would be lovely...
I also have two 1084S Monitors, 1989 with Din, and 1991 with
the DB connector. Both came with Amigas.
Charlie Fox
Charles E. Fox Video Productions
793 Argyle Rd. Windsor, Ontario
519-254-4991 N8Y 3J8
www.chasfoxvideo.com
-----------Original Message:
Date: Thu, 15 Nov 2007 08:32:02 +0000
From: Gordon JC Pearce <gordonjcp at gjcp.net>
Subject: Re: Speaking of multiple processors...
On Thu, 2007-11-15 at 00:32 -0500, Roy J. Tellason wrote:
> Didn't that "Superbrain" computer use a couple of Z80 chips in there? IIRC,
> one was the "main" CPU and the other one handled I/O tasks of some sort
> (disk?).
<snip>
It does. I believe one handles disk accesses, while the other does the
rest. Once I get mine working, I'll tell you more.<snip>
Gordon
----------Reply:
Cromemco also had Z80s on their I/O processor boards, and when the later 680x0
CPU boards dropped the Z80 you could still run your Z80 programs on the I/O card.
mike
I picked up a Data I/O 280 programmer this weekend, without manuals or
software. According to Data I/O's webpage, it's no longer supported at
all, so they have nothing available for download/purchase/whatever.
Anyone have software/manuals/anything for this thing?
Thanks as always,
Josh
