Online HelpPC 2.10 Quick Reference Utility Copyright 1991 David Jurgens
Media Descriptor Byte
Media Descriptor Byte Layout:
│7│6│5│4│3│2│1│0│ IBM Media Descriptor Byte
│ │ │ │ │ │ │ └─── 1 = 2 sided, 0 = not 2 sided
│ │ │ │ │ │ └──── 1 = 8 sector, 0 = not 8 sector
│ │ │ │ │ └───── 1 = removable, 0 = not removable
└─┴─┴─┴─┴────── must be set to 1
F8 Hard disk
Double sided 18 sector diskette PS/2 1.44 Mb. DSQD
F9 5¼ Double sided, High Density diskette (15 sector)
3½ Double Sided, Double High Density diskette (9 sector)
FA Ram disk (not all Ramdisks use this)
FC 5¼ Single Sided, Double Density diskette (9 sector)
8 inch Double Sided, Single Density diskette
FD 5¼ Double Sided, Double Density (9 sector)
8 inch Double Sided Single Density (26 sector) (IBM 3740
format) 128 bytes per sector, soft sector, 4 sectors
cluster, 4 reserved sectors, 2 FATs, 68 directory entries,
77*26*2 sectors.
FE 5¼ Single Sided, Double Density diskette (8 sector)
8 inch Single Sided, Single Density diskette (26 sector)
(IBM 3740 format) 128 bytes per sector, soft sector,
4 sectors per cluster, 1 reserved sector, 2 FATs. 68
directory entries, 77*26 sectors.
8 inch Double Sided, Double Density (8 sector), 1024 bytes
per sector, soft sector, 1 sector per cluster, 1 reserved
sector, 2 FATs, 192 directory entries, 77*8*2 sectors. To
distinguish from 8 inch SS/SD attempt read of side 2.
FF 5¼ Double Sided, Double Density diskette (8 sector)
- see also INT 21,1B INT 21,1C FAT
[helppc.bosbyte.nl] media descriptor byte