Altair 8800 Help

Hello, all, I recently acquired a very nice Altair 8800 with 40K of RAM (1 non-MITS 16K Static RAM board, and 3 MITS 4K Static RAM Boards, a MITS Version 1 8080 CPU Board, a MITS 2SIO, a MITS 88-DCDD floppy disc controller (two board pair), a MITS PROM board (8-slots for 1702 256-byte PROMS), a MITS 4-port Parallel card, and two MITS 8" floppy disc drive enclosures, along with a Televideo 912 Terminal, a heavily modified CT-1024 "TV-Typewriter", and a serial TI 810 printer, and an 18-slot (non-MITS) motherboard with an upgraded power supply. That along with boatloads of spare parts, a bus extender, a couple of unused S-100 bus prototyping cards, an unstuffed Ithaca Audio S100 board (not sure what it is), all of the original Altair documentation, a bunch of 8" floppies (including original various version of MITS (Micro-soft) BASIC, MITS DOS, and FORTRAN complier, and a bunch of documentation written by the former owner of the system. I very carefully inventoried everything first, then pulled out all of the boards from the CPU and tested out the power supply, first un-loaded, then under dummy loads, then powered it up with the front panel power leads connected, but no other boards, and all looked good. Then I plugged in the CPU board and the 16K static RAM board, and powered up and could reliably examine and deposit data into the RAM. I then wrote some simple test programs and toggled them in, such as reading the sense switches and storing their content into a memory location, setting all (as much of possible without getting too fancy) of memory to a specific value, then verifying it, and various other CPU functionality tests. All the little test I did passed with flying colors. I then added in the three 8K MITS RAM boards, and they all seemed to work fine also. Then I plugged in the 2SIO board, but didn't have a cable to connect the port clearly configured on the board as the console port to the terminal, so I've got some work to do there. Tonight, I'm hoping to write a little test code using HYPERTERM or the like on a laptop to read/write characters through the console port. The other port is configured strangely, and I need to do some jumper wire tracing to figure out how it's configured. So, the CPU itself seems great. Next, I checked out the floppy controller boards, making sure all of the chips were well-seated (they were all socketed), and checked the power supply lines and regulators to make sure they were OK. Put the board set into the system, plugged "DRIVE 0" into the CPU, and toggled in some very basic floppy controller functionality tests that are included in the manual for the controller, and tried out the tests. They all passed just fine per the results that should be obtained as mentioned in the manual. So, here's the dilemma. The PROM board is currently configured at a start address of 1 111 100 000 000 000 (174000 Octal, or 0xF800). I plugged all of the PROMs into the sockets (there were five different ROMs that I found, including one that had a label that indicated that it was some kind of BOOT ROM). I started examining memory at 0xF800, and found that most all of the PROMs contained all zeros...either erased, or suffering from failure due to extreme age (date codes of '76), and/or no covers over the windows. The one PROM that responded was the one that had the label hinting that it might be a boot PROM. So, I wrote down the content of the PROM and went about hand disassembling it. It does indeed appear to talk to the floppy controller, which is hard-coded at I/O Addresses 0x10, 0x11, and 0x12), as there are a lot of IN and OUT instructions referencing these I/O addresses. Looking at the various absolute jump addresses in the ROM, it appers to be coded to run at 0x4Cxx, or 046xxx Octal. If I set the start address of the ROM board to make this ROM appear in the proper place, it'll conflict with the RAM installed in the system. I have a number of disks which I'd like to try to boot from, including: ALTAIR DISK EXTENDED BASIC REVISION 4.1 JUNE 1977 COPYRIGHT 1988 BY MITS INC. Another disk with the following: MITS DISK OPERATING SYSTEM (DOS) VERSION #1.0 MFG: 03/13/78 COPYRIGHT 1977 BY MITS INC. FLOPPY DISK (NWD) SN: 10396 Which also has a label below this one saying FORTRAN COMPILER VERSION #2.8 MFG:06/05/78 COPYRIGHT 1978 BY MITS INC. COPYRIGHT 1978 BY MICROSOFT INC. (NWD) SN: 10152 Also on this same disk is a small label saying: (C)MICROSOFT 1977 ALBUQUERQUE, NEW MEXICO And another disk that says: ALTAIR COMPUTER CENTER BEAVERTON, OREGON DISK COPY UTILITY VERSION 2.0 14-APR-78 SN: 10058 7808 NOTE: THIS DISKETTE WILL NOT COPY ITSELF All of the labels on these disks are original manufacturer labels...these disks are the genuine thing, not copies. Clearly, I'd love to be able to boot these disks. I think that the floppy controller is good. The system even came with a Alignment Disk, so I toggled in some of the routines that would allow observation of the tracking (cats-eye) and index/sector (it's a hard-sectored controller) stuff with an oscilloscope, and everything looked perfect. I just need some bootstrap code. I've looked around in all of the documentation, and there's no boot code listed in the docs for the floppy subsystem. There are small bootstrap routines to load code over the 2SIO board (presumably from a paper-tape reader on an ASR-33 TTY), another from a parallel port (presumably from one of those little optical tape readers that you'd pull the tape through, wasn't it a company called OAE?), and another from cassette (but I don't have an interface board for cassette). I've thought of writing a small program that would copy the boot code out of the PROM into the proper space within RAM, and then JMPing to it, but not sure if that'll work or not...I suppose it's worth a try, but haven't done that yet. I've perused the web a lot looking for boot code for the Altair floppy controller, and haven't been able to find anything. Any Altair experts out there that might have some floppy boot code for the Altair 88DCDD floppy controller that might work to boot up the MITS DOS, or DISK EXTENDED BASIC floppies I've got? Also, anyone know the default console port I/O address that these products expect the serial console to be at? I assume the FORTRAN compiler runs under MITS DOS, and that's why the two products are together on the same disk. Right now I've only got one of the floppy drives connected up, but I'd expect that the FORTRAN compiler will need the 2nd drive in order to do anything useful, but I'm trying to take things one step at a time. I've got a manual for Altair DOS, and it does describe the disk format, so I suppose I could write a boot program myself, but it'd be a lot easier just to find someone that already has the stuff. Also, if anyone knows where Altair DOS and Disk Extended BASIC expect the serial console (e.g, I/O Port Address), that too would be helpful. If anyone could help, I'd sure appreciate it. Thanks in advance, Rick Bensene The Old Calculator (and sometimes Computer) Museum http://oldcalculatormuseum.com