FCB

Format of File Control Block:

Offset	Size	Description
00h	BYTE	drive number (0 = default, 1 = A, etc)
FFh is not allowed (signals extended FCB, see XFCB)
01h	8 BYTEs	blank-padded file name
09h	3 BYTEs	blank-padded file extension
0Ch	WORD	current block number
0Eh	WORD	logical record size
10h	DWORD	file size
14h	WORD	date of last write (see FILEDATE)
16h	WORD	time of last write (see FILETIME)
18h	8 BYTEs	reserved
20h	BYTE	record within current block
21h	DWORD	random access record number (if record size is > 64 bytes, high byte is omitted)

Notes

reserved field have different meaning in different DOSes. Not known is it used by OS/2 MVM.

SeeAlso

XFCB

SVC API
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Structures	FCB XFCB FILETIME FILEDATE