[cctalk] Re: Experience using an Altair 8800 ("Personal computer" from 70s)

Bill Degnan wrote: Although my Altair was "fully expanded" when I first owned it, I was involved with it quite some time before that: At University of New Brunswick I made friend: Gary -staff at computer center Gary found: Dan -former student -built the Altair -Decided to sell to Gary -- Dan had assembled a minimal system: Chassis, all Mits: CPU, 1K RAM, Serial -- Fortunately he had put in 3 of the 4-slot S100 boards (12 slots) Together Gary and I expanded it to a much more usable system --- 64K RAM, NorthStar Disks, ADM3A terminal and more I wrote an 8080 assembler on UNBs IBM 360 mainframe, which gave a good listing (code values) of our I/O routines. Using front panel: Run at E900 (Boot ROM - unpersonalized N*DOS), HALT, toggle-in I/O code, restart DOS in memory. This gave DOS talking to the ADM3A (yes - it took a few trys before we had it working) - then we loaded clean DOS into memory (DOS self-modifies in memory as it boots), use N*Monitor to copy our I/O to this copy, initialize a second disk and save DOS to it - this gave us a working DOS that booted! If you want to experience doing this, it can all be done on my Virtual Altair! For the true experience, you should stick to the front panel switches, but if you want to "cheat" - Virtual Altair has additional capabilities that original didn't: Full debugger with execution (disassembly) display, memory/register editors, 'L'oad Intel/Motorola hex images to memory while stopped! Sometime later, while testing bare code on a second Altair without disks, I created: MinimalCodeEntrySerialBoot This let me load/run large programs, having to toggle in only 18 bytes via the front panel! Ah, fond memories! -Dave