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AX = 5200h
Return:
AH = 80h (successful) if installed BX = internal JAM.SYS version number CX = size of JAMINFO structure (see #02831,#02832) DX = JAM.SYS segment address
Program: JAM.SYS is a main component of the JAM Real-Time Data Compression Utilities by George A. Reznik and friends (JAM Software).
See Also: AX=5201h
Format of JAMINFO v1.10 structure: Offset Size Description (Table 02831) 00h 25 BYTEs extended BIOS parameter block (BPB) 19h 11 BYTEs ??? 25h DWORD total number of sectors in JAM archive file (size of compressed data area) 29h BYTE flags (see #02833) 2Ah 127 BYTEs full JAM archive file name A9h WORD the number of fragments in archive file ABh 96 BYTEs archive file fragmentation list - array of 16 FRAGMENT structures (see #02834) 10Bh DWORD address of the host-drive DPB (Drive Parameter Block) 10Fh DWORD number of free sectors in JAM archive file 113h WORD device status word (see #02835)
See Also: #02832
Format of JAMINFO v1.20 structure: Offset Size Description (Table 02832) 00h 25 BYTEs extended BIOS parameter block (BPB) 19h BYTE physical driver number 1Ah BYTE reserved 1Bh BYTE extended boot record signature 1Ch DWORD volume serial number 20h 11 BYTEs volume label 2Bh 8 BYTEs file system ID 33h DWORD total number of sectors in JAM archive file (size of compressed data area) 37h BYTE flags (see #02833) 38h 128 BYTEs full JAM archive file name B8h WORD the number of fragments in archive file BAh 96 BYTEs archive file fragmentation list - array of 16 FRAGMENT structures (see #02834) 11Ah DWORD address of the host-drive DPB (Drive Parameter Block) 11Eh DWORD number of free sectors in JAM archive file 122h WORD device status word (see #02835)
Note: The first 33h bytes are copied from the archive file's boot sector
See Also: #02831
Bitfields for JAMINFO flags: Bit(s) Description (Table 02833) 2-0 reserved 3 (v1.20+) 4 enable direct write requests (Int 26h, non-DOS requests, etc.) 5 read-only mode 6 no write-behind caching 7 full undelete-compatible allocation strategy
See Also: #02831 - #02832
Format of JAM FRAGMENT structure: Offset Size Description (Table 02834) 00h WORD starting sector (low word) 02h BYTE starting sector (high byte) 03h WORD size of fragment (low word) 05h BYTE size of fragment (high byte)
See Also: #02831 - #02832
(Table 02835) Values for JAM.SYS status (high byte): 00h successful 01h drive is not a JAM drive 02h drive is already attached 03h archive file cluster size value is larger than driver's one 04h drive is not attached 05h drive is locked 06h drive is not locked 07h bad physical-level request 08h host drive reading/writing error 09h bad entries in JAM descriptor table 0Ah compressed data integrity error 0Bh archive file overflow 0Ch bad DOS request 0Dh incorrect parameters in JAMINFO structure
Note: The low byte of the status is the DOS error code for the Host drive
See Also: #02598 at INT 2F/AX=0802h
Category: File/Disk Compression - Int 2Fh - J
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