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Write Hard Disk Sector

Write Hard Disk Sector

Write Hard Disk Sector

Hi All,

Can anyone please advise? I have a QBasic set of routines one of which allows me to read a Hard Disk sector via interrupt 13h, information found from Ralph Browns interrupts, - this works without error:


InRegs.CX = &H1 ' Get sector 1 of track zero
InRegs.DX = (Head% * 256) + Disk%   '   of selected drive
InRegs.AX = &H201                   ' Read one full sector
InRegs.BX = VARPTR(Sector)          ' Offset of read buffer
InRegs.ES = VARSEG(Sector)          ' Segment of read buffer

CALL INTERRUPTX(&H13, InRegs, OutRegs) ' Read sector

but I would like to be able to write back the sector, again using interrupt 13h I use the same notation as the above snoppet but this fails, (I use InRegs.AX = &H301 which according to Ralph Browns Interrupt list should write back the sector read)

Either I have the AX register value wrong or clearly something else so I'm wondering if anyone may be able to guide me in the right direction to a resolution?

I have seen the QBasic FAQ which talks about disk access but this seems only pertinent to floppy drives and I'm dubious to try the cod on a hard disk!

Many thanks for your time

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