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:
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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.