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Equalizer700
November 3rd, 2008, 01:25 PM
I'm resurrecting my 1975 hand-built Altair. I'm looking for 8" floppies with CP/M 2.2 for an Altair with Tarbell controller and DualStor disk drives. Any leads will be greatly appreciated.

I also would like some advice on resurrecting some cassette tapes with Basic and ASM on them...I have an 88-ACR and the tape drive, but the tapes are so old I'm afraid to load them unless I am sure what I'm doing. Is there any PC software that will find and/or restore any dropped bits?

Does anyone know the format of the DualStor disks? SS or DS? SD or DD? Hard or soft sectored?

Any help or advice is welcome!

John

billdeg
November 22nd, 2008, 07:34 PM
John can you post a detailed pic of your controller? Some of the key wire jumper locations?
thanks.
bill

Chuck(G)
November 25th, 2008, 09:49 AM
I probably have the boot floppy that I used with my Altair with the original Tarbell controller and MITS SIO card. No guarantees, but if it's still readable, I could send you a BIOS listing to peruse. Drop me a PM if you're interested.

Equalizer700
January 1st, 2009, 09:42 AM
Bill and Chuck,

Sorry to have dropped out of sight for a month or two. Had to spend some time in the hospital but now everything is ok.

Bill, I have put high resolution pics of the Tarbell controller at www.speedreferrals.com/pic1.jpg through pic 4.jpg. As you'll see there are lots of jumpers on the back side (as with lots of things of that era). It looks like the board might have been jumpered to be a Rev B, since there is a B scratched on the back side. If you would like a better pic of an area of the board I will be happy to get it for you. There are no jumpers on the component side, just a dip switch.

Chuck, I appreciate the offer of a BIOS listing, but I don't know how to get from that to a bootable floppy. Do you know anyone who has the facilities to copy a disk? I have read that there are ways to read and write 8" floppies using a PC floppy interface cable and an adapter of some sort. Do you know who the experts are on this subject?

I really appreciate your help!

John

Terry Yager
January 1st, 2009, 11:09 AM
Happy to see ya back on your feet. Stay well.

--T

billdeg
January 6th, 2009, 10:44 AM
Here is mine
http://www.vintagecomputer.net/tarbell/tarbell_MDL_1011D_disk-controller.jpg

Chuck(G)
January 6th, 2009, 04:11 PM
Chuck, I appreciate the offer of a BIOS listing, but I don't know how to get from that to a bootable floppy. Do you know anyone who has the facilities to copy a disk? I have read that there are ways to read and write 8" floppies using a PC floppy interface cable and an adapter of some sort. Do you know who the experts are on this subject?

Yes, you can make an adapter (or just get one from DBit (http://www.dbit.com/fdadap.html) Probably not a bad thing to have around in any case...

But, the Tarbell (mine looks just like Bill's) controller uses a WD1771 single-density controller, so your PC has to be capable of supporting FM recording mode. Not all are.

Fortunately, there's an easy way to separate the wheat from the chaff. Attached is a DOS executable called TESTSD.EXE. It attempts to format and read track 74 on the first 1.44MB 3.5" drive on your PC. Just boot DOS (can even reside on the test diskette), run TESTSD and look at the output.

I can supply an image in many formats; Dave Dunfield has written Image Disk which is a good one, but I can also supply TeleDisk images or any other format you'd care for.

I also have the manual for the Tarbell controller, if it's not online. Configuring those jumpers for your drives can get to be a head-scratcher without a guide.

Equalizer700
January 12th, 2009, 05:34 AM
Bill,
Chuck,

Wow, thanks for the info! I have looked on all sorts of other boards and haven't found anyone else who even knows what I was talking about.

Believe it or not, my current PC doesn't even have a floppy drive...just the cable. I ordered a drive from Newegg and will run the test Chuck sent when I get it. I also have some other, older PCs lying around...I'm sure one of them will work.

I'll start saving my allowance for a dbit adapter, too.

I'll let you know the results...

Thanks again!

John

virtualaltair
March 5th, 2009, 05:50 PM
Hi John,

How is your Altair Tarbell project going? I'm resurrecting my Altair/Tarbell/Vector Graphic project and have some questions:

What model of Altair do you have and what boards are in it? I'm especially interested in how much RAM amd which IO board.

You mention DualStor disk drives. Are these Vector-Graphic disk drives? If so, are they the original Dual-Stor or the newer Dual-Stor?

The following page has Dual-Stor pictures for reference:

http://vector-graphic.info/vg_dual_stor.aspx


Tom
www.virtualaltair.com
www.vector-graphic.info

chuckcmagee
March 5th, 2009, 07:51 PM
Hey hey hey. If and when I get my 8" drives working, that Dbit thing sounds like just the ticket. Guess I'll have to run around and test with your SD test deal too. I wasn't having much luck finding a CP/M that was preconfigured for the Tarbell. Looks like take a closer look at the drives is the first order of biz.

Chuck(G)
March 5th, 2009, 10:29 PM
You can always run an emulator under DOS/Windoze to build your binaries and then use something like 22Disk to write the boot tracks to an 8" drive.

Are you still interested in a source code for a BIOS using the Tarbell?

Depending on your 8" drive (whether or not it needs TG43/RWC), you might be able to get away without the dbit thing and just build your own PC-to-8" cable. It's not hard.

chuckcmagee
March 6th, 2009, 01:21 AM
Yes on the source code. chuckcmagee at msn dot com.

For $40 + shipping, I would much rather have a nice pretty neat Dbit sitting here instead of a hack sawed edge connector off a floppy drive, with a bunch of somewhat well soldered too large wires running all over the place.

I do own one of those fancy Wellers but I got it off of ebay. Most of the time, seems like it doesn't get hot enough --- Now we know why it was on ebay.

virtualaltair
March 6th, 2009, 03:48 AM
Interfacing 8-inch drives to a PC is also a project I want to to try. TESTSD.EXE says my Turbo XT should work.

Here is link to my Tarbell 1011D project page:

http://vector-graphic.info/vg_tarbell_1011d.aspx

The Tarbell MDL 1011D pictured once worked in an Altair or a Vector Graphic machine.

Equalizer700
March 8th, 2009, 08:55 AM
Hi Tom,

I have the original DualStor drives...the green/white one with the two drives together as one unit. I also have a Peripheral Vision dual drive cabinet with only one drive. As I remember it, I was one of the first people do have a floppy on the Altair, so it is all early stuff.

As for memory configuration, as the box was when I got it our of storage it had a Memory Merchant 16K board, a MITS 4K board and a Seattle Computer Products 16K board in the chassis. I also have some loose 4, 8 and 16K boards from other manufacturers.

It has a 2SIO IO board and a EProm board with the boot loader. I also have the Eprom for loading from cassette.

Do you know if the DualStor has SS/SD drives?

As for the Altair project, I'm not having much time to work on it between regular work and digging my driveway out of all the snow. But today it is warming up and starting to melt and the at work project should finish this week...so I hope to get back to it soon.

Would you (or anyone?) be willing to split the cost of the Dbit adapter and share it's use? Or maybe we can make disks for each other? Surely someone has already done this and can make disks at will?

John

Chuck(G)
March 8th, 2009, 10:18 AM
You know that you don't have to hack into cables.

Just get a small hunk of perf board, install two headers on it--one 50-pin, the other 34-pin and wire the two up. Since half the connections are grounds, it shouldn't take you long. Plug a 50-pin female to 50-pin edge cable onto one header and your 8" drive and a standard 34-conductor floppy cable on the other.

Microsolutions used to sell a setup very like this, except said board was a small PCB.

Or make your own DBIT thingie. You could do it with an 8-pin PIC; you need only sample TK00 from the drive and STEP and DIR and DSEL from the controller--assert RWC/TG43 when you determine that the drive's in the right place. Assemble it on some perfboard.

Easily only an afternoon's worth of work.

Terry Yager
March 8th, 2009, 12:07 PM
You know that you don't have to hack into cables.

Just get a small hunk of perf board, install two headers on it--one 50-pin, the other 34-pin and wire the two up. Since half the connections are grounds, it shouldn't take you long. Plug a 50-pin female to 50-pin edge cable onto one header and your 8" drive and a standard 34-conductor floppy cable on the other.

Microsolutions used to sell a setup very like this, except said board was a small PCB.

Or make your own DBIT thingie. You could do it with an 8-pin PIC; you need only sample TK00 from the drive and STEP and DIR and DSEL from the controller--assert RWC/TG43 when you determine that the drive's in the right place. Assemble it on some perfboard.

Easily only an afternoon's worth of work.

Mine is from CDR Systems, P/N 85002. It even has jumpers to ground out pin #34 of the 50-pin and #2 on the 34-pin side if necessary. It came as a bare PCB, I had to pop the headers myself, but it's a very simple setup and could be easily copied on perfboard.

--T

virtualaltair
March 8th, 2009, 06:43 PM
> ďÖ maybe we can make disks for each other? Surely someone has already done this and can make disks at will?Ē

The Tarbell has been interfaced to an Altair many times. There are multiple threads with requests for help, however, I havenít found a complete documented solution. Hopefully, more people will help, however, Altair owner may be very busy or the Altair system is in storage or no longer working. My goal is to document a solution and make a supply of boot disks and/or boot images available.

> ďI have the original DualStor drives...the green/white one with the two drives together as one unit.Ē

Can you provide an image for my Dual Stor page? http://vector-graphic.info/vg_dual_stor.aspx
Does your Dual Stor have a stand-alone power supply or use a regulator board and power from the mainframe?

> ďDo you know if the DualStor has SS/SD drives?Ē

The 1977 VG catalog says the Dual Stor disk system has a capacity of 243K bytes and uses the standard IBM compatible format. That indicates that the drive is SSSD. It would be good to know the drive manufacturer and model. Drive specific jumper settings may be required for the drive or Tarbell. Iíd also like to compare the jumper settings on your Tarbell 1011A to the D revision.

Iím documenting the configuration for a Tarbell 1011D, Shugart SA 801, Pertec FD 514, and later Qume DT/8 on my page http://vector-graphic.info/vg_tarbell_1011d.aspx. The Tarbell manual documents the configuration for several other drives

> ďIt has a 2SIO IO board and a EProm board with the boot loaderĒ

Good, the Altair 88-2SIO is probably what most people have in an Altair. http://www.virtualaltair.com/virtualaltair.com/vac_88-2SIO.ASP
I also plan to document the Intel 8251A implementation for Vector Graphic computers.

I assume you have a front-panel Altair. Iím using turnkey computers and require a separate boot loader prom. That requires Tarbell switch 1-7 to be off to disable the Tarbell 82S123 Bootstrap prom.

> ďAs for memory configuration, Ö.Ē

I asked about memory configuration, since any boot disks provided must be configured for available memory. A 64K CP/M boot disk for an 8800b Turnkey wonít be useful to many people. A 48K CP/M will work on a 56K Vector Graphic. A 32K CP/M will be handy for people with a shortage of memory boards.

> ďWould you (or anyone?) be willing to split the cost of the Dbit adapter and share it's use? ď

Iím saving my pennies for a Dbit, but first must find spare time and get my drives up and running. Iíll try my Compaticard first, but would like to document use of the Dbit and the software required to make Tarbell boot disks on a PC. I have Uniform PC, but donít know anything about 22Disk. Will we end up copying a 8-inch disk, or need to assemble BIOIS ASM using an emulator?

You may want to take a look at the Altair Peripheral Emulator (APE) for a quick way to use CP/M on an Altair. This tool is still useful with a Tarbell. You can find it in the reference links Iím adding below.

Related Links

Looking for Tarbell CP/M Boot Disks (altaircomputerclub message 1413)
http://groups.yahoo.com/group/altaircomputerclub/message/1413

Tarbell is making me insane. From: Grant Stockly
Classic Computing Mailing List Archive
http://archive.netbsd.se/?ml=cctech&a=2007-11&m=5623418

FDADAP floppy disk adapter.
http://www.dbit.com/fdadap.html

"The D Bit FDADAP board is a small adapter which adapts 8" floppy disk drives (Shugart SA800 style bus) to work with the PC 3.5"/5.25" floppy disk cable pinout"

APE - To mimic: The Altair Peripheral Emulator
http://frankbarberis.tech.officelive.com/default.aspx

"The Altair Peripheral Emulator is a program that allows a Windows PC to emulate up to four floppy disk drives for an Altair 8800 series computer"


Tom Sanderson
www.virtualaltair.com
www.vector-graphic.info

virtualaltair
March 12th, 2009, 11:03 AM
Hi Tom,

I have the original DualStor drives...the green/white one with the two drives together as one unit. I also have a Peripheral Vision dual drive cabinet with only one drive. As I remember it, I was one of the first people do have a floppy on the Altair, so it is all early stuff.

As for memory configuration, as the box was when I got it our of storage it had a Memory Merchant 16K board, a MITS 4K board and a Seattle Computer Products 16K board in the chassis. I also have some loose 4, 8 and 16K boards from other manufacturers.

It has a 2SIO IO board and a EProm board with the boot loader. I also have the Eprom for loading from cassette.

Do you know if the DualStor has SS/SD drives?

As for the Altair project, I'm not having much time to work on it between regular work and digging my driveway out of all the snow. But today it is warming up and starting to melt and the at work project should finish this week...so I hope to get back to it soon.

Would you (or anyone?) be willing to split the cost of the Dbit adapter and share it's use? Or maybe we can make disks for each other? Surely someone has already done this and can make disks at will?

John

Iím like you, I have limited time to work on this project. It's been 30 years since I solved this problem and I am slowly remembering and researching the details. I looked a Chuck's BIOS and remembered that some people had a monitor prom and used it for console IO. You didnít mention a monitor prom, but did mention a boot loader prom. Did you have the DualStor working with your Tarbell in the past? If so, I can assume your controller and drives have the proper jumper setup.

I have two BIOS versions. The Vector Graphic BIOS version used a monitor prom and the Altair version has BIOS code for the Altair 88-2SIO. I have my original hardware, but it didn't boot when I tried it a few years ago. There are several people that have used a Tarbell with an Altair. I don't know how many still have their system up and running.

My boot and BIOS code is on 8-inch disks and I want to make it available, but first I need to get some 8-inch drives working. I see from reading the replies to your first message, that one approach is to interface 8-inch drives to a PC. That approach will be useful to get my code, but will require me to set up tools on the PC to assemble the BIOS code. There are several parts to this problem: 1) Find time for the project; 2) Get the hardware working; 3) Interface drives to the Tarbell; 4) Interface drives to a PC; 5) Set up development software; and 6) Assemble a boot disk.

Hopefully, your drives and Tarbell are in good shape. I have to put my drive system back together as a first step. If the drives donít work with my S-100 machines, Iíll try the PC approach to test the drives. Iíll try my Compaticard first and then maybe the Dbit. My original drives are Pertec and require a 10ms step rate. I can set the step rate with the Compaticard, but donít know how to do that with the Dbit. I have a Shugart SA801 and a pair of Qume DT/8 drives. Both need a power supply and connector.

I hope we can find someone with a working system that can make boot disks. If not, Iíll try to get my S-100 hardware to boot again or at least read my source code disks on a PC. After that, Iíll need to re-learn how to assemble a boot disk. So, assuming your hardware is in good shape, your Tarbell and drives are jumpered correctly, we need a boot disk that initializes a 2SIO and is configured for available memory. What size of CP/M do you need on a boot disk?

virtualaltair
March 14th, 2009, 08:00 PM
I started with two Tarbell 1011D controllers, two Pertec FD514 drives, and two 8-inch boot disks. If found one of each pair was bad. Using the good components, I was able to boot 56K CP/M 2.2 configured for Vector Graphic IO and monitor prom. My next project is get a second drive working so I can copy diskettes. Iíll also need to get my 8-inch software library out of storage and find some blank diskettes.

At this point, I could move the controller and drive to an Altair and test the 60K Altair boot disks that I found. Iím going to try for a second drive first. Iíll also look for the diskette the with boot prom and BIOS source code. This should be good news for anyone with a 60K Altair, however. Iíd like to publish the source code and make some 48K or smaller boot diskettes.

Tom Sanderson
www.virtualaltair.com
www.vector-graphic.info

MikeS
March 14th, 2009, 09:36 PM
And of course you can often replace the 8" drives with 5 1/4" HD drives; some people swear by TEACs, while Rich Cini (IMSAI/Compupro) and I (Cromemco) have had good luck with YE Data drives. I've also used Panasonics but if there are several drives on the cable it's better to have drives with a head load solenoid. Even if you have an 8" drive it's handy to have a 5 1/4" equivalent as well, for copying/backing up, and restoring images on a PC.

Chuck(G)
March 14th, 2009, 10:00 PM
I located the boot sector code that didn't use the monitor ROM for I/O, but does use Z80 opcodes:



;* CP/M SYSTEM BOOT.
;
; LOADS AT ADDRESS 0, READS IN CP/M
;

DCMCH EQU 0F8H ; COMMAND PORT FOR DISK
DSTCH EQU 0F8H ; STATUS PORT FOR DISK
DSLCH EQU 0FCH ; SELECT/WAIT PORT
DTKCH EQU 0F9H ; TRACK PORT
DSCCH EQU 0FAH ; SECTOR PORT
DDTCH EQU 0FBH ; DATA PORT

CRTCH EQU 0 ; CRT PORT

MSIZE EQU 60 ; MEMORY SIZE IN K
VERS EQU 2 ; CP/M VERSION

TOP EQU MSIZE*1024 ; TOP ADDRESS OF MEMORY
CBOOT EQU TOP-600H ; COLD BOOT ENTRY
CCP EQU TOP-1C00H ; CCP LOAD ADDRESS

ascbel equ 7 ; ascii bell code

NSECTS EQU 33H ; DISK SECTORS TO LOAD

ORG 0000H

ENTRY: MVI E,5 ; RETRY COUNT
ENT1: MVI A,2
OUT DSCCH ; SET SECTOR 2/TRACK 0
LXI B,(128 SHL 8) OR DDTCH ; FOR INI
MVI D,NSECTS ; SECTOR COUNT
LXI H,CCP ; STARTING LOCATION
ENT2: MVI A,098H ; READ MULTIPLE SECTORS
OUT DCMCH ; ISSUE COMMAND
ENT4: IN DSLCH ; WAIT FOR DATA
RAL ; GET INTERRUPT BIT
DB 30H,ENT6-$-1 ; JR NC,ENT6
DB 0EDH,0A2H ; INI
DB 20H,(ENT4-$-1) AND 0FFH ; JR NZ,ENT4
MVI B,128 ; NEW DATA COUNT
DCR D ; SECTOR COUNT
DB 20H,(ENT4-$-1) AND 0FFH ; JR NZ,ENT4
JMP CBOOT ; GO JOIN BOOT CODE

ENT6: IN DSTCH
CPI 10H ; CHECK FOR SNF
DB 20H,(ENT8-$-1) ; JR NZ,ENT8
IN DSCCH
CPI 01BH ; LOOKING FOR SECTOR 27?
DB 20H,(ENT8-$-1) ; JR NZ,ENT8 NO...
MVI A,58H ; STEP IN
OUT DCMCH
IN DSLCH ; WAIT FOR IT...
MVI A,1
OUT DSCCH ; SET SECTOR 1
DB 18H,(ENT2-$-1) AND 0FFH ; JR ENT2 CONTINUE...

ENT8: DCR E
DB 20H,(ENT10-$-1) ; IF NOT OUT OF RETRIES
lxi h,wbmsg
WBERR: MOV A,M
ora a
db 20h,(WBER2-$-1) ; if not end
hlt ; stop

wber2: in crtch
ral
db 38h,(wber2-$-1) and 0ffh ; loop until ready
mov a,m
out crtch+1
inx h
db 18h,(wberr-$-1) and 0ffh

ENT10: MVI A,10H
OUT DCMCH ; RESTORE
in dslch ; wait for completion
DB 18H,(ENT1-$-1) AND 0FFH ; JR ENT1 GO TRY AGAIN...

wbmsg: db 7,13,10,'Boot Loader Error',0

ORG 07DH

JMP ENTRY ; BOOT ENTERS HERE

END

virtualaltair
March 14th, 2009, 11:35 PM
And of course you can often replace the 8" drives with 5 1/4" HD drives; some people swear by TEACs, while Rich Cini (IMSAI/Compupro) and I (Cromemco) have had good luck with YE Data drives. I've also used Panasonics but if there are several drives on the cable it's better to have drives with a head load solenoid. Even if you have an 8" drive it's handy to have a 5 1/4" equivalent as well, for copying/backing up, and restoring images on a PC.

Thanks Mike,

Iím looking forward to trying 5.25-inch HD drives. I recently worked with Tandon TM100-4M 100TPI 5.25-inch drives. They are rare and have a couple of places where the old brittle plastic cracks. (http://vector-graphic.info/vg_tandon_parts.aspx) I was told Andrew Lynch had success using Panasonic JU-475s with the Vector Graphic hard-sectored controllers.

Some drives are a pain to work with. Now, Iím working with Pertec FD514 drives. These drives have old brittle plastic in the door & bezel. The Pertec drives are still use in airline flight simulators. The last price I saw was around $1300 and the vendor was out of stock. I have a couple of Qume DT/8 drives and a Shugart SA801. Each of these drives has a different power connector and different voltages than the Pertec drives. The Pertec drives are 2/3 height and the replacements wonít fit in the cabinet.

I want to make a supply of Altair/Tarbell 8-inch boot disks while I can, however, my main goal is to retrieve source code from my 8-inch diskettess. As you suggest, it would be a good idea to move the software to 5.25-inch HD diskettes. Using 5.25-inch HD drives and diskettes should allow me to use original controllers and preserve old software. After I copy the software from 8-inch SSSD diskettes, I plan to use FD514 parts to repair Pertec FD510 drives and restore some Altair drive cabinets. That is a case where saving the cabinet and 8-inch drives has some value. Iím wondering when/if someone will interface a 5.25-inch drive to MITS hard-sectored controllers.

Iím making web pages to document the old drives, show how to use newer drives, and provide software. Information and images from anyone is appreciated. Topics of interest are model number, jumper settings, and cables for 5.25-inch HD drives. Also, Tarbell 1011D, Tandon TM100-4M and Micropolis 1-15-IIB 100TPI drives, Pertec drives, CP/M BIOS source, and links to web information. There is great information on several forums, but it is hard to jump around and put it all together. Several people have started and discussed projects, but a few details are missing like jumper settings and where to get a boot disk. Iíd also like images for people that want to learn, but donít own the equipment. Thanks everyone.

Tom Sanderson
www.virtualaltair.com
www.vector-graphic.info

Chuck(G)
March 15th, 2009, 12:09 AM
I’m looking forward to trying 5.25-inch HD drives. I recently worked with Tandon TM100-4M 100TPI 5.25-inch drives. They are rare and have a couple of places where the old brittle plastic cracks. (http://vector-graphic.info/vg_tandon_parts.aspx) I was told Andrew Lynch had success using Panasonic JU-475s with the Vector Graphic hard-sectored controllers.

Don't forget the Micropolis 100 tpi drives. Also the MPIs. Of the three brands, the Micropolis ones were built like a battleship and are least likely to fail--but are the slowest because of the leadscrew positioner used.



Some drives are a pain to work with. Now, I’m working with Pertec FD514 drives. These drives have old brittle plastic in the door & bezel. The Pertec drives are still use in airline flight simulators. The last price I saw was around $1300 and the vendor was out of stock. I have a couple of Qume DT/8 drives and a Shugart SA801. Each of these drives has a different power connector and different voltages than the Pertec drives. The Pertec drives are 2/3 height and the replacements won’t fit in the cabinet.

Siemens FDD-100 (single sided) and FDD-200 (double-sided) 8" drives are pretty nearly indestructible. I think the 100's even have die-cast faceplates.


I want to make a supply of Altair/Tarbell 8-inch boot disks while I can, however, my main goal is to retrieve source code from my 8-inch diskettess. As you suggest, it would be a good idea to move the software to 5.25-inch HD diskettes.

Why not use 22Disk? :) A1 format.


Using 5.25-inch HD drives and diskettes should allow me to use original controllers and preserve old software. After I copy the software from 8-inch SSSD diskettes, I plan to use FD514 parts to repair Pertec FD510 drives and restore some Altair drive cabinets. That is a case where saving the cabinet and 8-inch drives has some value. I’m wondering when/if someone will interface a 5.25-inch drive to MITS hard-sectored controllers.

A lot of 5.25" HD drives time the index to determine when the drive is ready. Hard-sectored disks mess this up and the drive never comes ready. HD hard-sectored diskettes never existed to the best of my knowledge.


I’m making web pages to document the old drives, show how to use newer drives, and provide software. Information and images from anyone is appreciated. Topics of interest are model number, jumper settings, and cables for 5.25-inch HD drives. Also, Tarbell 1011D, Tandon TM100-4M and Micropolis 1-15-IIB 100TPI drives, Pertec drives, CP/M BIOS source, and links to web information. There is great information on several forums, but it is hard to jump around and put it all together. Several people have started and discussed projects, but a few details are missing like jumper settings and where to get a boot disk. I’d also like images for people that want to learn, but don’t own the equipment.

Are you looking for the manual for the Tarbell 1011? I have that.

virtualaltair
March 15th, 2009, 04:57 AM
Don't forget the Micropolis 100 tpi drives. Also the MPIs. Of the three brands, the Micropolis ones were built like a battleship and are least likely to fail--but are the slowest because of the leadscrew positioner used.


Iím not familiar with MPIs. I agree about the Micropolis Drives, solid and slow. The only Micropolis problem I found recently, was excessive lube on the door latch that got real thick and sticky. I concentrated on the Tandons because most of my software is on double-sided diskettes. Also, the Tandons and Micropolis drives use a different controller in Vector Graphic systems.

http://vector-graphic.info/vg_micropolis_10115_IIB.aspx
http://vector-graphic.info/vg_micropolis_fd_control_b.aspx
http://vector-graphic.info/vg_tandon_tm100_4m.aspx
http://vector-graphic.info/vg_fd_hd_controller_b.aspx




Why not use 22Disk? :) A1 format


I havenít learned 22Disk yet and am out of time for now. Posting a 22Disk link and some info would be good for this thread. I did configure Microsolutions Uniform and a Compaticard for Pertec Drives. So far no luck, but Iíll try again later now that Iím learning which drives work. I still need power for my SA801 and Qume DT/8 drives. I was wondering about 22Disk and the Dbit. Can I set the step rate to 10ms for the Pertec drives?



A lot of 5.25" HD drives time the index to determine when the drive is ready. Hard-sectored disks mess this up and the drive never comes ready. HD hard-sectored diskettes never existed to the best of my knowledge.


I havenít had time to follow up on Andrew Lynchís work, but hear that the Panasonic JU-475s work with the VG controller. The disks are still hard sector, but not compatible with 100TPI. Thatís progress, but 16-hard-sectored diskettes are still hard to find.



Are you looking for the manual for the Tarbell 1011? I have that.


I have hard copy, but need a pdf for a web page. A rev A and rev B schematic would be good to have. Also, I would like to document the Tarbell jumper settings for 5.25" HD drives.

I found the .asm, .prn, and .hex SBOOT & BIOS files for 48K & 60K Altair CP/M and 56K Vector Graphic CP/M. Iím about out of time to work on S-100 projects, so Iíll try booting a diskette, starting modem 7.12 and then swap diskettes to transfer the files over RS-232. Then I can put the files on the web for others. Hopefully you and others can describe how to build a CP/M boot disk with a PC, Dbit, and 22Disk. I can SYSGEN a 48K or 60K boot disk for John (Equalizer700). I canít put files on the disk until I get two drives running, unless I can use APE with a Tarbell and single-drive.

http://frankbarberis.tech.officelive.com/default.aspx

I can also make CP/M boot disks for MITS hard-sectored controllers. CP/M boots OK, but I still need to get a modem program and some CP/M utilities to the hard-sectored boot disk.


Tom Sanderson
www.virtualaltair.com
www.vector-graphic.info

Chuck(G)
March 15th, 2009, 10:33 AM
I’m not familiar with MPIs. I agree about the Micropolis Drives, solid and slow. The only Micropolis problem I found recently, was excessive lube on the door latch that got real thick and sticky. I concentrated on the Tandons because most of my software is on double-sided diskettes. Also, the Tandons and Micropolis drives use a different controller in Vector Graphic systems.

There was also the Micropolis 1016 drive. As far as I can tell, the only difference is the "door closed" microswitch activation mechanism. The 1015 uses a longish lever, while the 1016 extends the microswitch body to make contact with the frame.

The earlier Micropolis drives (with the anodized blue door latch) had a problem of creasing the disk hub area if the motor wasn't on when a disk was inserted. Later drives fixed this by turning the motor on briefly as the door was closed.

There are double-sided 100 tpi Micropolis drives. One thing that never changed over the models was the leadscrew itself. If you had access to, say, a 1115-VI 96 tpi DS drive, you could take a 1015 leadscrew assembly and convert the 1115 to DS 100 tpi.

The MPI drives were poorly made in my experience,with a nasty tendency to break door stops if they were too vigorously opened.

(FWIW, my experience is not with VG systems, but only that I worked with a company that used 100 TPI drives between 1977 and 1983.)


I haven’t learned 22Disk yet and am out of time for now. Posting a 22Disk link and some info would be good for this thread. I did configure Microsolutions Uniform and a Compaticard for Pertec Drives. So far no luck, but I’ll try again later now that I’m learning which drives work. I still need power for my SA801 and Qume DT/8 drives. I was wondering about 22Disk and the Dbit. Can I set the step rate to 10ms for the Pertec drives?

The step rate is configurable. You can set the step rate down to 4 msec if that suits you. Controller cards can be located at any I/O address, use any 8-bit DMA and IRQ.


I haven’t had time to follow up on Andrew Lynch’s work, but hear that the Panasonic JU-475s work with the VG controller. The disks are still hard sector, but not compatible with 100TPI. That’s progress, but 16-hard-sectored diskettes are still hard to find.

Almost any quad-density (720K) 5.25" drive should work. And I'd prefer Teac 55F's in that case. Very sturdy drives that can be had with head-load mechs. There are many 96 tpi QD drives available. It's the HD drives that are too smart for their own good.

You can also replace an 8" soft-sectored disk drive with a 3.5" drive capable of 1.23MB support (sometimes called a "tri-mode" drive). Samsungs in particular are cheap and also support a READY signal as well as 360 RPM operation.

This might make media availability less of a problem.

What's the "A" revision for the Tarbell? My manual doesn't list any revision at all--just "Model 1011". The schematic's dated 6/1/77.

MikeS
March 15th, 2009, 11:29 AM
A couple of years ago I wanted to replace the TM100s and TM848s in my Cromemcos and the 100TPI Micropolis drives in the VG MZs with more modern 5 1/4 DD & HD drives, since those are more reliable and easier to find.

I started to compile a list of specs for different drives, but there were so many variables that I gave up after I found some drives that worked for me and some other folks wanting to do the same thing; maybe I'll get back to it some day.

Almost all HD drives were capable of dual speed (300/360) operation, but not all had jumpers and when they did the settings varied all over the place even with variations of the same make/model.

Another issue was the relation between speed and density, and the usage of pin 2.

All drives that I tried could be set to emit /READY instead of the PC Disk change signal, although, again, not all had a jumper and those that did were not very standard. Note that on the other hand the VG Micropolis drives did not follow the 'standard' /READY pinout.

As Chuck says, many would not go ready with a hard-sector disk, including IIRC the TEACs that I tried.

Finally, there was the issue of motor control and head load (if relevant) and, for the 8" emulation, the track 43 signal; also the trivial issue of when to light the LED.

Bottom line: all 5 1/4 HD drives are *definitely NOT* the same; there's a wide range of capabilities and configurations, and the requirements for replacing 96 or 100TPI QD (and HS) 5 1/4" drives are not the same as for replacing 8" drives.

BTW, Chuck: whatever happened to the hard-sector synthesizer that you (and Andrew) were working on?

Chuck(G)
March 15th, 2009, 11:42 AM
BTW, Chuck: whatever happened to the hard-sector synthesizer that you (and Andrew) were working on?

After frustrating Andrew to no end and losing some of my own hair, I found that at least with modern drives, the instantaneous (less than one rev) speed variation was considerable. I was computing my results out to 16 bits and it still flopped.

Somewhere, I've got a log of the variations on a Teac FD-55GH drive and it's surprising. So the simple scheme of "time one rev and use it for the next one" doesn't really work well enough to be ready for prime-time.

At this point, it seems that the most likely solution is to select a given drive model and tap into the tach circutry to get an accurate idea of how fast the disk is moving from moment to moment.

Given that, I'm not sure this is something that anyone is interested in.

We might all be better off by replacing our floppies with a solid-state solution (that's a project I"m currently working on, as well as a replacement for ST-506/412 type hard drives).


Finally, there was the issue of motor control and head load (if relevant) and, for the 8" emulation, the track 43 signal; also the trivial issue of when to light the LED.

Many later-manufacture 8" drives keep track of where the heads are and internalize the TG43/RWC signal. The pin on their interface is essentially an NC.

virtualaltair
March 15th, 2009, 02:58 PM
What's the "A" revision for the Tarbell? My manual doesn't list any revision at all--just "Model 1011". The schematic's dated 6/1/77.


Here is a picture from John (Equalizer700) of a Tarbell MDL 1011A http://www.speedreferrals.com/pic1.jpg

I Have a Rev.C Schematic dated 7-19-77 that came with my MDL 1011D. I was mistaken about having a Rev D. Schematic. The Rev C schematic is marked Size D. Iím probably getting into too my detail, but was trying capture information about Tarbell variations. At first glance Johnís 1011A looks a lot different than my 1011D because it uses the connector in the middle, doesnít have wires on the front, and has white sockets for U46, U47, U48, and U64. Iíll stop worrying about Tarbell variations and be happy that my four boards are all 1011D.

I am wondering about the revisions for the FD Control B board on Pertec FD514 drives. Last night, I replaced a -06 Shugart compatible board with a -03 MITS compatible board. Later, Iíll find my manual and someone who can read schematics. For now, the MITS version appears to be working as my B: drive. The drive has given me a new perspective on the concept of Computer Virus. A mouse has been living in the drive and I worry about the Haunta virus. That is one more reason for me to move away from 8Ē drives. A second drive does make it easier to download the SBOOT and BIOS files, so that is my next task.


The step rate is configurable. You can set the step rate down to 4 msec if that suits you. Controller cards can be located at any I/O address, use any 8-bit DMA and IRQ.


I was told to only use a 10ms step rate with Pertec drives and that should work with other drives. Will a boot disk I produce be likely to cause problems in other systems. Now that I have the source code, I should at least document the step rate setting.


Bottom line: all 5 1/4 HD drives are *definitely NOT* the same; there's a wide range of capabilities and configurations, and the requirements for replacing 96 or 100TPI QD (and HS) 5 1/4" drives are not the same as for replacing 8" drives.


Iím getting more interested in software emulators. Drive replacement sounds difficult for someone who is not a hardware engineer.



We might all be better off by replacing our floppies with a solid-state solution (that's a project I"m currently working on, as well as a replacement for ST-506/412 type hard drives).


I like this idea very much. A solid-state solution for Pertec drives would be good for Altair owners and could also be useful for airline flight simulators. I wonder how many flight simulators are in use and require 2/3 height 8Ē floppies. For now, Iím happy to get a couple more Vector Graphic computers and Altairs working with old drives.

Iím getting close to having a 48K CP/M boot disk for John (Equalizer700). If he gets his Altair out of the garage and upgraded to 48K, he can try the Tarbell 1011A and Vector Graphic DualStor. Iíd like to get a picture of the older DualStor and know what brand/model of 8Ē drives were used. I think the drives are SSSD and hope they like a 10ms step rate.


Tom Sanderson
www.virtualaltair.com
www.vector-graphic.info

virtualaltair
March 15th, 2009, 08:26 PM
Yes, you can make an adapter (or just get one from DBit (http://www.dbit.com/fdadap.html) Probably not a bad thing to have around in any case...

But, the Tarbell (mine looks just like Bill's) controller uses a WD1771 single-density controller, so your PC has to be capable of supporting FM recording mode. Not all are.

Fortunately, there's an easy way to separate the wheat from the chaff. Attached is a DOS executable called TESTSD.EXE. It attempts to format and read track 74 on the first 1.44MB 3.5" drive on your PC. Just boot DOS (can even reside on the test diskette), run TESTSD and look at the output.

I can supply an image in many formats; Dave Dunfield has written Image Disk which is a good one, but I can also supply TeleDisk images or any other format you'd care for.



I should have read this message more carefully and done more research. I found the information on Image Disk on Dave Dunsfieldís excellent page:

http://www.classiccmp.org/dunfield/img/

In addition to Image Disk, there is information on connecting 8Ē and external floppy drives plus modifying a 1.2M drive for 300 rpm. I like Daveís pages because they have great images and detailed technical information. I didnít see Altair/Tarbell listed on the System / Install disk page, so I think my goal should be to make a set of Altair/Tarbell boot disks that can be used to make images.


I also have the manual for the Tarbell controller, if it's not online. Configuring those jumpers for your drives can get to be a head-scratcher without a guide.


I found the Tarbell manual in the Harte Technologies website: http://www.hartetechnologies.com/manuals/Tarbell/ . This Tarbell manual includes a Rev C schematic that is marked OK for Rev. D.

I have the Tarbell jumper settings for a Pertec FD514 -06 revision and the Shugart SA-801 are in the Tarbell manual. Next, Iíll need to find a manual for a Qume DT/8 or find someone who has interfaced a Qume to a Tarbell. Hopefully the drives in Johnís DualStor are documented in the Tarbell manual or his MDL 1011A is already configured.

It will likely be awhile before I have 8-inch drives on my PC or can interface a 5.25Ē or other drive. Hopefully someone can provide more Tarbell jumper settings (not already in the manual) or volunteer to make Image Disk or TeleDisk images.

Tom Sanderson
www.virtualaltair.com
www.vector-graphic.info

virtualaltair
March 23rd, 2009, 05:03 AM
CP/M 2 BIOS, BOOT, and Utilities for Tarbell MDL 1011D and Altair 88-2SIO

http://www.virtualaltair.com/virtualaltair.com/vac_altair_tarbell_1011d_software.asp


www.virtualaltair.com

Marty
July 26th, 2009, 12:16 PM
Hi All;
I have a Tarbell controller, single density. But, I don't know IF I have it wired right. First for 8" floppies, and second for 3.5" floppies... Yes, I know the 8" are a 50 pin, and 3.5 is a 34 pinout... Also I think the Main Chip 1771 is Bad, where do I Get another one ?????....
I also have a double Density controller that came with my Z-80 system, and would like to use it on my Altair (8080).... it is a SBC 880 system...I have the schematics and the software listings, but when I try to match things up to write software for the altair things get mixed up. there are more ports and under different names than the Tarbell...
THANK YOU Marty