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Format of Extended BIOS Data Area (see 40:0Eh for ptr) [PS only]
Offset Size Description
00h BYTE Length of EBDA in kilobytes
01h 15 BYTEs reserved
17h BYTE Number of entries in POST error log (0-5)
18h 5 WORDs POST error log (each word is a POST error number)
19h-21h reserved
22h DWORD Pointing Device Driver entry point
26h BYTE Pointing Device Flags 1
bit 7: =1 command in progress
bit 6: =1 resend
bit 5: =1 acknowledge
bit 4: =1 error
bit 3: =0 reserved
bits 2-0: index count
27h BYTE Pointing Device Flags 2
bit 7: =1 device driver far call flag
bits 6-3: reserved
bits 2-0: package size
28h 7 BYTEs Pointing Device Auxiliary Device Data
2Fh BYTE reserved
30h DWORD Vector for INT 07h stored here during 80387 interrupt
34h DWORD Vector for INT 01h stored here during INT 07h emulation
38h BYTE Scratchpad for 80287/80387 interrupt code
39h WORD Timer3: Watchdog timer initial count
3Bh BYTE ??? seen non-zero on Model 30
3Ch BYTE ???
3Dh 16 BYTEs Fixed Disk parameter table for drive 0 (for older machines
which don't directly support the installed drive)
4Dh 16 BYTEs Fixed Disk parameter table for drive 1 (for older machines
which don't directly support the installed drive)
5Dh-6Bh ???
6Ch BYTE Fixed disk: (=FFh on ESDI systems)
bits 7-4: Channel number 00-0Fh
bits 3-0: DMA arbitration level 00-0Eh
6Dh BYTE ???
6Eh WORD current typematic setting (see INT 16/AH=03h)
70h 167 BYTEs ???
117h WORD keyboard ID (see INT 16/AH=0Ah)
119h and up: ??? seen non-zero on Model 60
3F0h BYTE Fixed disk buffer (???!!!)
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