Mail Archives: djgpp/1998/03/08/08:01:05
Eli Zaretskii (eliz AT is DOT elta DOT co DOT il) wrote:
: advice. Theoretically, you could make a DJGPP version 1000 times
: slower if you, for example, called the BIOS for every byte you needed
: to read. Calling BIOS requires a mode switch which is slow, so you
: should make as few calls as you can. In particular, reading more of
: the disk at a time and then working on data in memory should speed
: your program a lot. In DJGPP, you could even read an entire diskette
: into memory in one swell whoop.
No Eli, you can't - most floppy disk BIOSes do not support reading more
that one cylinder's worth of data in a single call. Even if your particular
BIOS can do it (something you shouldn't rely upon), 8-bit DMA channel
used by floppy drives won't allow you to transfer more than 64Kb worth
of data without re-initialization. Even if your BIOS can miraculously
circumvent this limitation, you won't have enough low memory to buffer
the data coming from a single HD floppy anyway. Don't I love PCs...
Regards,
/Serge.P
--
Russian guy from the Zurich university...
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