Format of DOS 2.x disk buffer:
Offset Size Description )
00h DWORD pointer to next disk buffer, offset = FFFFh if last
least-recently used buffer is first in chain
04h BYTE drive (0=A, 1=B, etc), FFh if not in use
05h 3 BYTEs unused??? (seems always to be 00h 00h 01h)
08h WORD logical sector number
0Ah BYTE number of copies to write (1 for non-FAT sectors)
0Bh BYTE sector offset between copies if multiple copies to be written
0Ch DWORD pointer to DOS Drive Parameter Block (see #01395 at AH=32h)
10h buffered data
SeeAlso: #01650,#01652,#01653,#01655