[fpc-pascal] Low level disc access under windows with FPC

Vinzent Hoefler JeLlyFish.software at gmx.net
Mon Oct 9 11:03:55 CEST 2006

On Sunday 08 October 2006 12:08, Pianoman wrote:

>         Hello, I'd like to ask if someone has experiences with low
> level disk operations in windows with FPC.
> The program should be able to copy entire diskete to one single image
> file and for example extract a single file from that image or view
> its contents.


-- 8< -- snip --
To open a disk for direct access, you use the Win32 CreateFile function 
with a special format to specify the name of the disk (a floppy or a 
partition on a hard disk): "\\\\.\\a: " to open the a: floppy and "\\\.
\\c: " to open the c: partition on a hard disk.

On hard disks, you can even get direct access at the physical device 
level, bypassing the partition structure. This is done with the special 
name "\\\\.\\PhysicalDriveN," where N is the number of the hard disk, 
starting with 0. If you have only one physical hard disk, it's 
PhysicalDrive0, no matter how many partitions you have.
-- 8< -- snip --

So creating a floppy image seems fairly easy (provided you have the 
rights to access the disk in that way at all), but extracting a file 
from a disk image may be harder because that would require knowledge of 
the file system in question unless Windows has some sort of "mount" 
feature for such image files.



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