fulton@comet.dec.com (Cathy Fulton -- CXO Technical Training) (10/12/87)
Does anyone have info on what interrupt 52H does? It is an
undocumented interrupt. It is a pointer to the start of a chain
of blocks that tells you what programs DOS has loaded in memory.
I am mainly interested in finding out what the format of these
blocks are.
Thanks for any replies.fulton@comet.dec.com (Cathy Fulton -- CXO Technical Training) (10/12/87)
(Sorry to repost this, but I forgot to include my e-mail addresses
the first time I posted this.)
Does anyone have info on what interrupt 52H does? It is an
undocumented interrupt. It is a pointer to the start of a chain
of blocks that tells you what programs DOS has loaded in memory.
I am mainly interested in finding out what the format of these
blocks are.
Thanks for any help.
- Cathy
uucp: ...decwrl!comet.dec.com!fulton
ARPA: fulton@comet.dec.combill@hpcvlo.HP.COM (Bill Frolik) (10/14/87)
Are you sure you mean int 52H? On my system (running PC-DOS 3.2) it points at F000:C3E3, a default interrupt handler in the BIOS ROMs. Bill Frolik hp-pcd!bill Hewlett-Packard Portable Computer Division Corvallis, Oregon 97330
martyl@rocksvax.UUCP (Marty Leisner) (10/14/87)
In article <11819@decwrl.DEC.COM> fulton@comet.dec.com (Cathy Fulton -- CXO Technical Training) writes: > > Does anyone have info on what interrupt 52H does? It is an > undocumented interrupt. It is a pointer to the start of a chain > of blocks that tells you what programs DOS has loaded in memory. > I am mainly interested in finding out what the format of these > blocks are. > This is the information I have from the list posted by Ralf Brown and Dan Lanciani. If anyone has more complete information, I'd like to see it. INT 21 - Internal - Get Disk List AH = 52H Return: ES:BX points to DOS list of lists List of Lists: Bytes Value 0-3 Pointer to first DOS disk block (see func 36H) 4-7 Partially Unknown. Pointer to a device driver. Maybe first resident driver? 8-B Partially Unknown. Pointer to a device driver. Maybe first resident character device driver? C-F Pointer to actual CON: device driver, whether installable or resident 10-11 Unknown. 0200H. A byte/blocksize value??? 12-15 Unknown. Pointer to current directory block???? 16-19 Partially Undefined: Pointer to array of drive info: 51H bytes per drive, starting with A: ... 00-3F Current path as ASCIIZ, starting with 'x:\' 40-43 Unknown. I see zeros always 44 Unknown. Flags? I see 40H, except for entry after last valid entry = 00H 45-48 Pointer to DOS Disk Block for this drive 49-4A Unknown. Current track or block? -1 if never accessed. 4B-4E Unknown. I see -1 always 4F-52 Unknown. I see 2 always 1A-1D Unknown. Pointer to data area, maybe including cluster allocation table? 1E-1F Unknown. I see zero always 20 Unknown. May be number of block devices. 21 Unknown. May be number of resident devices or ??? (5 always) 22 Beginning (not a pointer. The real beginning!) of NUL device driver. This is the first device on DOS's linked list of device drivers. ------------------------------------------------ Flame on!! I really hate this reverse engineering. Anyone with source code who wants to leak (??) what's going on. Flame off!! marty -- marty leisner xerox corp leisner.henr@xerox.com martyl@rocksvax.uucp
ralf@B.GP.CS.CMU.EDU (Ralf Brown) (10/18/87)
In article <156@rocksvax.UUCP> martyl@rocksvax.UUCP (Marty Leisner) writes: >This is the information I have from the list posted by Ralf Brown and Dan Lanciani. If anyone has more complete information, I'd like to see it. > >INT 21 - Internal - Get Disk List > AH = 52H ... >-- >marty leisner >leisner.henr@xerox.com >martyl@rocksvax.uucp I'd also like to see any additional info anyone has on functions 52h, 5Dh, (and for DOS 3.3) 64h, 65h, 66h, and 68h. I will then repost the list with the additional information. I will repost the list in uuencoded ARC format on or about November 1. -- {harvard,uunet,ucbvax}!b.gp.cs.cmu.edu!ralf -=-=- AT&T: (412)268-3053 (school) ARPA: RALF@B.GP.CS.CMU.EDU |4 line .sigs|"I do not fear computers.|DISCLAIMER? FIDO: Ralf Brown at 129/31 | are a pain | I fear the lack of |I claimed BITnet: RALF%B.GP.CS.CMU.EDU@CMUCCVMA | them..." --Isaac Asimov |something?