This is it folks, the original MITS Altair 8800 (approx serial number 3000). It was assembled from the original 1975 chassis and REV-A CPU board and upgraded later to include monitor board, extra memory, printer board and some others. The main breadboard was also probably upgraded as it is copyrighted 1977.
thing about this system is that it works! Instructions can be entered
with switches at the front and then run (now I just have to break out
my 8080 binary instruction manual!).
More on the Altair 8800 from DigiBarn Visitor Valerie Kramer:
I had an Altair 8800 back in the "good ol' days". A friend and I went to "The Computer Store" in Los Angeles and we each bought one. I remember my carton was numbered "13". I don't know if that was lucky or not but I did get it working eventually. I think I still have some photos somewhere though
I sold the unit off long since. As I recall, I couldn't afford a video card for output (or maybe there were none available yet) so output was via a parallel port to a "TV Typewriter" project I had built from plans in Popular Electronics. Later I switched to an ASR33 teletype that I found at a surplus place in Chatsworth.
Despite the huge transformer and gigantic electrolytic capacitors in the power supply, it wasn't nearly as stable as modern switching power supplies.
I learned that if I plugged the system into the wrong outlet in the house, the system would crash every time the refrigerator came on. It also proved unusable when I tried to demonstrate it in my office at a manufacturing plant. Sometimes the "good 'ol days" weren't all that good!
Rebooting was a royal pain. To load the BASIC interpreter, one had to load in a 21 byte sequence via the toggle switches then run it and hope it loaded correctly which it did about every third or fifth try. I finally sat down and wrote a bit of assembler code to allow me to load memory from the keyboard or to run the standard boot program from ROM. I burned the program one bit at a time into a PROM chip using a 6V battery. I think I had a few other useful options in this monitor-type program as well. It sure made the Altair a lot more friendly!
By the time I was done playing with it, my Altair had floppy disk drives and other refinements. Like most, I have shed most of these pieces of history over the years. I currently still have a couple of CP/M systems boxed up (one including Valdocs) and I keep a couple copies of IBM DOS 1.0 for my retirement fund. :)
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