Altair 8800 simulator

Ein CP/M-Simulator von Peter Schorn, basierend auf dem SIMH-Projekt. Emuliert wird ein 8080, Z80, diverse Floppy-Controller, MMU, etc.

http://schorn.ch/altair.html

the simulator features 8 simulated hard disks with a capacity of 8MB (HDSK0 to HDSK7). Currently only CP/M supports two hard disks as devices I: and J:.

Start: altairz80.exe <conf>

z.B. altairz80.exe cpm22

Ende:

q{uit} or by{e} or exi{t}

das dskdef-Format für die 8MByte HDISK (Standardformat 8megAltairSIM, es gibt noch andere Formate, s. Quellcode!)

HDSK (standard simulated AltairZ80 hard disk with 8’192 kB capacity) 8 MByte HD Format:

# ALTAIRZ80 SIMH *dsk
diskdef 8megAltairSIMH
  seclen 128
  tracks 2048
  sectrk 32
  blocksize 4096
  maxdir 1024
  skew 0
  boottrk 6
  os 2.2
end

The file format is that of SimH: a file image is just a stream of blocks.

d tracks[0-7] 254

The 88-DISK controller The MITS 88-DISK is a simple programmed I/O interface to the MITS 8-inch floppy drive, which was basically a Pertec FD-400 with a power supply and buffer board built-in. The controller supports neither interrupts nor DMA, so floppy access required the sustained attention of the CPU. The standard I/O addresses were 8, 9, and 0A (hex), and we follow the standard. Details on controlling this hardware are in the altairz80_dsk.c source file. The only difference is that the simulated disks may be larger than the original ones: The original disk had 77 tracks while the simulated disks support up to 254 tracks (only relevant for CP/M). You can change the number of tracks per disk by setting the appropriate value in TRACKS[..]. For example „D TRACKS[0] 77“ sets the number of tracks for disk 0 to the original number of 77. The command „D TRACKS[0-7] 77“ changes the highest track number for all disks to 77.

The 88_DISK is a 8-inch floppy controller which can control up to 16 daisy-chained Pertec FD-400 hard-sectored floppy drives. Each diskette has physically 77 tracks of 32 137-byte sectors each.

CPM 3 Byte + 128 Byte Daten + 7 Byte