Altair-Duino Pro
- General
- Project Diary
- Front Panel Switches
- Instructions
- Communicating via ...
- Configuration, Reset ...
- Displaying, mounting & booting a MITS (88-DCDD) disk drive
- Displaying, mounting & booting a MITS (88-HDSK) hard disk drive
- Serial connection for file exchange
... using Kermit, PCGET/PCPUT and PIP - Disk formats (8" & 5.25")
- Information
- Links
Altair 8" Diskette Format
330 KByte: 77 tracks, 32 sectors/track, 137 bytes/sector / single sided / hard sectored
;--------------------------------------------------------------
; Altair 8" Diskette Format
;--------------------------------------------------------------
; Raw Bytes/sector: 137
; Sectors/Track: 32, numbered 0-31
; Tracks/Diskette: 77, numbered 0-76
;
; Tracks 0-5 are formatted as "System Tracks" (regardless of
; how they are actually used). Sectors on these tracks are
; formmatted as follows:
;
; Byte Value
; 0 Track number and 80h
; 1-2 Number of bytes in boot file
; 3-130 Data
; 131 0FFh (Stop Byte)
; 132 Checksum of 3-130
; 133-136 Not used
;
; Tracks 6-76 (except track 70) are "Data Tracks." Sectors
; on these tracks are formatted as follows:
;
; Byte Value
; 0 Track number and 80h
; 1 Skewed sector = (Sector number * 17) MOD 32
; 2 File number in directory
; 3 Data byte count
; 4 Checksum of 2-3 & 5-134
; 5-6 Pointer to next data group
; 7-134 Data
; 135 0FFh (Stop Byte)
; 136 Not used
;
; Track 70 is the Altair Basic/DOS directory track. It is
; formatted the same as the Data Tracks, except that each Data
; field is divided into 8 16-byte directory entries. The last 5
; of these 16 bytes are written as 0 by most versions of Altair
; Basic and DOS, but are used as a password by Multiuser Basic,
; where five 0's means "no password". Unfortunately, single-
; user Basic does not always clear these bytes. If these bytes
; are not all 0 For a given directory entry, then multiuser
; Basic will not be able to access the file. /P fixes this. The
; first directory entry that has FFh as its first byte is the
; end-of-directory marker. (This FFh is called "the directory
; stopper byte.")
;--------------------------------------------------------------
Altair 5.25" Minidisk Format
75 KByte: 35 tracks, 16 sectors/track, 137 bytes/sector / single sided / hard sectored
;--------------------------------------------------------------
; Altair Minidisk Format
;--------------------------------------------------------------
; Raw Bytes/sector: 137
; Sectors/Track: 16, numbered 0-15
; Tracks/Diskette: 35, numbered 0-34
;
; On a bootable Altair Basic minidisk, tracks 0-11 are System
; Tracks. On a CP/M minidisk, tracks 0-5 are System tracks.
; Sectors on these tracks are formatted the same as system
; tracks on an 8" diskette.
;
; The remaining tracks of a bootable minidisk, and on all
; tracks of a non-bootable data minidisk are formatted the
; same as sectors on Data Tracks on an 8" diskette, except
; that the sectors are not skewed.
;
; Track 34 is the Altair Minidisk Basic directory Track.
; Sectors on this track are formatted the same as the Directory
; Track on an 8" diskette.
;--------------------------------------------------------------