DOS 3.0 Specific Information

% Offset Size Description

10 byte number of block devices

11 word max sector size used by DOS prior to loading block

device drivers; limits allowable device sector size

13 dword pointer to DOS cache buffer header

17 dword pointer to drive information table

1B byte value of LASTDRIVE command in CONFIG.SYS

1C dword pointer to STRING= workspace area

20 word size of STRING area (CONFIG.SYS value of STRING=x)

22 dword ~FCB~ file table pointer

26 word number of protected FCBs

28 18bytes NUL device header, first 4 bytes of device header

point to the next device in device chain