ALtair UIO Board?

Discuss construction, troubleshooting, and operation of the Altair 8800c computer

ALtair UIO Board?

Postby toml_12953 » March 24th, 2019, 5:26 pm

I'm looking for a working Altair UIO board (combination serial port and cassette interface) for my 8800c.

I'd need either a tested/assembled new repro board or a new, blank repro board with a BOM and instructions or an original board.
I'm a user, not a collector so I'd like a working board and "original" holds no special meaning for me.

If you've read my previous posts, you know I have very limited hardware skills which is why I specified WORKING. In fact,
I'm surprised my 8800c works as well as it does (perfectly). That's a testament to Mike Douglas, Martin Eberhard and the
makers of the 9-slot backplane board, CPU board repro and the VI/RTC board repro more than it is to my skill.

If anyone knows where I could get a UIO, PLEASE let me know! Thanks.

Tom L
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Re: ALtair UIO Board?

Postby AltairClone » March 25th, 2019, 4:42 pm

I have a UIO board in unknown condition. I'll work on it one day soon and let you know if it's a good fit for your 8800c.

Mike
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Re: ALtair UIO Board?

Postby toml_12953 » March 25th, 2019, 8:30 pm

AltairClone wrote:I have a UIO board in unknown condition. I'll work on it one day soon and let you know if it's a good fit for your 8800c.

Mike

I'd appreciate it! Maybe you'd consider making a bare repro board with a BOM?
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Re: ALtair UIO Board?

Postby virtualaltair » March 31st, 2019, 11:39 pm

I agree this board should be copied. MITS or KCACR cassette support plus a serial port all on one board.

My spare 88-UIO has not had cassette function tested. I did test the serial port. What boards are in your 8800c? An 88-2SIO, 88-2SIOJP, or Turnkey Module? The 88-UIO can provide a port for Console, Modem, Serial Printer, or maybe Timesharing Terminal.
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Re: ALtair UIO Board?

Postby toml_12953 » April 1st, 2019, 8:19 pm

virtualaltair wrote:I agree this board should be copied. MITS or KCACR cassette support plus a serial port all on one board.

My spare 88-UIO has not had cassette function tested. I did test the serial port. What boards are in your 8800c? An 88-2SIO, 88-2SIOJP, or Turnkey Module? The 88-UIO can provide a port for Console, Modem, Serial Printer, or maybe Timesharing Terminal.


I have the new front panel interface board, the CPU board, an FDC+, two 2SIOJP boards and an 88-VI/RTC board. I can run Timesharing BASIC with all four terminals operating. It's rather slow when all sessions are doing heavy computing but when two or three programs are waiting for input, it's reasonable. I'd like to use the UIO serial port for a serial printer but is that supported by BASIC?

Tom L
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Re: ALtair UIO Board?

Postby virtualaltair » April 4th, 2019, 1:40 am

You are building a great power user system!

I'm not sure about serial printer connections and BASIC. I just noticed BASIC 4.0 does not have a printer prompt. More Altair details to learn.

My RS-232 book has a story about an Altair dealer being killed because of a customer's printer wiring problem. Your new 88-C700C board should solve the printer problem. What model of Centronics Printer do you have? The 88-C700-C board will need a jumper for interrupts for Timesharing BASIC, I think.

Your second 2SIOJP port with CTS enable would support a Remote CP/M system on single user BASIC. I have not studied the signals on the UIO port. Is CTS 5V or really CTS?

How much RAM per user on a 4 user Timesharing System? FYI, the creator of Business BASIC 4 wrote a version of BB4 for the MITS 300/55. Business Basic swapped 4K chunks of code to the Pertec hard disk drive allowing larger programs. I think the code was moved to the PCC2000. The MITS version is probably lost.

Did I count 8 boards for a 9-slot backplane? What board is next? Is the power supply OK with a full backplane? I'm glad FDC+ includes RAM.
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Re: ALtair UIO Board? (Revised)

Postby toml_12953 » April 4th, 2019, 8:21 am

virtualaltair wrote:You are building a great power user system!

How much RAM per user on a 4 user Timesharing System? FYI, the creator of Business BASIC 4 wrote a version of BB4 for the MITS 300/55. Business Basic swapped 4K chunks of code to the Pertec hard disk drive allowing larger programs. I think the code was moved to the PCC2000. The MITS version is probably lost.

Did I count 8 boards for a 9-slot backplane? What board is next? Is the power supply OK with a full backplane? I'm glad FDC+ includes RAM.


I have a Centronics HPC-136-3B (anyone have docs on that? I can't find them) There are about 9000 bytes free per user in TS BASIC with four users.

You counted correctly. My boards:

Code: Select all
Slot     Board
1      Front Panel Interface (New version - Ribbon cable is much nicer than the original rat's nest of wiring.
             I assembled it myself and it actually works!)
2      CPU - I assembled it myself and it actually works too!
3      VI/RTC (Vectored Interrupt/Real-Time Clock) (INT Level 1) I also assembled this myself and it works too! I'm on a roll!
4      FDC+ (64K RAM, Floppy disk Interface, ROM) (I/O address 8d, INT Level 0) I have two Shugart SA-800
             hard-sectored 8" drives in a Xerox case hooked up to this.
5      ********* Free!!! **********
6      C-700 Centronics Interface (I/O address 2d, INT Level 7)
7      UIO Serial/Cassette Interface board (ACR: I/O address 6d, Serial: I/O address 24d, INT Level 3)
8      2SIOJP (two serial ports) (I/O addresses 16d and 18d, INT Level 2)
9      2SIOJP (two more serial ports) (I/O addresses 20d and 22d, INT Level 3)


I have one whole slot left! Maybe for a Dazzler II?

Where can I download (or buy) a copy of your book? I'm always on the lookout for Altair history!

Is a copy of BB4 available somewhere? I'd be interested in the larger space for my AltairDuino although I have no way to use a hard drive with my 8800c.
Last edited by toml_12953 on April 9th, 2019, 3:20 am, edited 4 times in total.
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Re: ALtair UIO Board?

Postby AltairClone » April 4th, 2019, 10:40 am

toml_12953 wrote:I'd like to use the UIO serial port for a serial printer but is that supported by BASIC?


Altair Basic 4.0 supported only the 88-LPC board ("O"kidata) and did not prompt for the printer type. Later versions of BASIC supported the "O"kidata, "C"entronics, and "Q"ume printers. I think Timesharing BASIC supports only the Centronics and Qume printers. There is no native support for a serial printer in Altair BASIC, though the low-level print routines in regular versions of BASIC can be patched as described in the Altair BASIC manuals.

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Re: ALtair UIO Board?

Postby virtualaltair » April 4th, 2019, 11:38 pm

Thanks again Mike! My only experience is with the working Business versions - 300-5-C & 300-5-F. Future work will be done in 300-5-F, CP/M MBASIC4, and BASCOM /4.

What is the status of Centronics support in Altair CP/M? I like the 88-C700C because it works with both old and new dot-matrix printers. Our Altair Accounting team used a Printronix P150 line printer. Users without printers are not power users because they can't run Altair Accounting Software.

I think the Altair Book is Mike's websites. He consolidates Altair technology and history from others. He also creates new history with by creating new tools that allow Altair History to continue. People like toml prove the "Altair" bus was a great idea and the Altair is not dead. A old "normal" Altair would have a mixture of boards.

An 88-4PIO would fill the empty slot and provide a Hard Disk interface. Martin may have the only working Pertec drive. A HD+ board would be great. A simulator or clone may be the answer.

I suggest adding a Tarbell 1011D. BOOT, BIOS, and CP/M are available with 2SIO/M6850 support. What do you suggest Mike? Can the 8800C power supply power a full motherboard?
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Re: ALtair UIO Board?

Postby virtualaltair » April 5th, 2019, 12:19 am

I don't know much about MITS Timesharing BASIC. There was not enough user memory and no file manager for multi-user accounting. Tom, did you know Mike made clock routines that used the 88-VI/RTC?

I mentioned Business BASIC to alert Altair fans to look for a D3000 disk pack with "MTX". MTX was developed by an Altair dealer for the 300/55.

The Altair history was that we ported ASDC floppy disk accounting to the 300/55. That involved a new menu for multiple modules and a change to end of month floppy swapping procedures. Software maintenance required a 300/55. Lots of Altair BASIC programs stored /A in ASCII. The software was still buggy and and not multi-user.

MAI BASIC 4 broke with their dealer network. That made multi-user Business Basic software available. The new Pertec division made of ex-Phillips NA employees favored a multi-user accounting call Magic. Altair Accounting died. MTX and MAGIC were ported to the PCC 2000. Pertec did not know how to move programs from MAI computers to the PCC 2000. No one volunteered except me. I wrote a crude BASIC program to transfer characters using RS-232. The PCC 2000 became multi-user and then died

CP/M, single user accounting, and S-100 lived longer, but not MITS or Pertec. The Turnkey Module with the CLG mod plus stable, better 300-5-C BASIC and stable, faster 300-5-F BASIC support 64K Altairs that we can use now. They are a result of improving speed for Altair Accounting.

Now toml & Mike will discover 88-UIO history and save and document two 88-UIO boards.
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