feg@floyd.ATT.COM (Forrest Gehrke,2C-119,7239,ATTBL) (06/17/91)
I am having difficulty trying successfully to code in C an absolute disk read using the alternate (extended) method for INT 25 required for reading into a disk partition greater than 32MB. Particularly, my problem is with the disk read packet DS:BX which requires (and here I am quoting from Ralf Brown's INT291 listing for this INT): 00h DWORD Sector Number 04h WORD Number of sectors to read 06h DWORD Transfer address Sector number: is this the absolute sector number starting from the partition sector, or is it the DOS boot sector? If accessing the boot sector is this number 0? Transfer Address: To where? How is this address chosen? If anyone has coded this successfully in C I would appreciate receiving via email the code fragment involved. Thanks, --Forrest Gehrke feg@dodger.att.com
android@ccwf.cc.utexas.edu (Andy Wilks) (06/18/91)
In article <1991Jun17.164151.2625@cbnewsl.att.com> feg@floyd.ATT.COM writes: >I am having difficulty trying successfully to code in >C an absolute disk read using the alternate (extended) >method for INT 25 required for reading into a disk >partition greater than 32MB. > >Particularly, my problem is with the disk read packet >DS:BX which requires (and here I am quoting from >Ralf Brown's INT291 listing for this INT): > >00h DWORD Sector Number >04h WORD Number of sectors to read )06h DWORD Transfer address ) )Sector number: is this the absolute sector number starting )from the partition sector, or is it the DOS boot sector? )If accessing the boot sector is this number 0? ) )Transfer Address: To where? How is this address chosen? This is the buffer where you want the data read FROM the disk to go. you need to allocate it in your program and pass it to int 25h or 26h as a far pointer. Make the buffer as big as the sector(s) you want to read. E-mail me if you need more details. ) )If anyone has coded this successfully in C I would appreciate )receiving via email the code fragment involved. ) >Thanks, > >--Forrest Gehrke feg@dodger.att.com /*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/ * I don't express opinions, I just follow orders... (___) * / (o o) / * Andy Wilks One of the few .sig's-> /-------\ / * / andy@fiskville.mc.utexas.edu with ASCII livestock. / | ||O / * android@ccwf.cc.utexas.edu * ||,---|| * / University of Texas at Austin ^^ ^^ / * copyright (c) 1934,1942,1961,1990,1991 BEVO * /*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/