Problem reading/writing sectors

Posted on 1998-03-25
Last Modified: 2012-05-04
I made a program in Turbo Pascal 7.0 that sometimes reads sectors (using REGS and INTR standard procedures) from a floppy disk and writes it back to the same sector when my program do some modifications to the information, But sometimes in Windows 95 (DOS box) when I do this operation many times, the program "read" the sector but not writes its contents back (no writes anything). When I try this program in Windows NT (MS-DOS Console), it reads the sector but not writes back anything(!). What happen in this two cases? I need DPMI or something? The program works without problems in Win95 DOS Only-Mode and DOS 6.x. Thanks a Lot!!!
Question by:mapadu2000
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Expert Comment

ID: 1217417
Windows 95 and Windows NT 4.0 use different FATs. I think there is the problem.

Author Comment

ID: 1217418
What programming tool (language) I need for re-write the application as Win32 Console App? Thanks a Lot

Expert Comment

ID: 1217419
it depends, if u still want a program designed for DOS or (Dos-Mode) i think it can be done with BP7 (protected mode) or if you wish a 32-bit win-exe you could use Delphi, this is pascal based
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Author Comment

ID: 1217420
In Delphi, How I can read/writes sectors? Can you give me an example code? Thanks

Expert Comment

ID: 1217421
I suggest you to compile your program in BP7 protected mode and try if it works in that mode.

Expert Comment

ID: 1217422
you can't do direct disk reads in windows.

from win32sdk.hlp:

Windows NT: You can use the CreateFile function to open a disk drive or a partition on a disk drive. The function returns a handle to the disk device; that handle can be used with the DeviceIOControl function.

Accepted Solution

jlove1 earned 50 total points
ID: 1217423
before running the program under windows 95.. Try using the LOCK command
lock a:

This will allow the program to have "DIRECT" access to the sectors on the drive by bypassing dos.


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