From: Pace Willisson pace@blitz.com
Subject: b.com floppy driver patch for fast machines
Date: Wed, 30 Aug 1995 08:11:56 -0400 [thread overview]
Message-ID: <19950830121156.gzKL5_eNG3gR1nJKb9dZalXrYFI3qnhbsRhrd9J9eX0@z> (raw)
My shiny new 133 mhz pentium was getting "premature EOF" errors when
trying to boot from a floppy. This patch to floppysend() fixes it up:
*** sys/src/boot/pc/floppy.c- Tue Aug 29 15:48:28 1995
--- sys/src/boot/pc/floppy.c Tue Aug 29 15:48:46 1995
***************
*** 367,373 ****
int tries;
uchar c;
! for(tries = 0; tries < 100; tries++){
/*
* see if its ready for data
*/
--- 367,373 ----
int tries;
uchar c;
! for(tries = 0; tries < 1000; tries++){
/*
* see if its ready for data
*/
I'm a little surprised that this was all I needed to do. On older
machines, the inb in the loop would have run at the 8mhz ISA bus speed
and would have completely dominated the processor time. Perhaps i/o
to this motherboard's built in floppy controller runs much faster. In
that case, a better fix might be to do a dummy i/o cycle to a real ISA
port, or use a calibrated delay, like clock.c:delay, but scaled for,
perhaps, 10 microseconds per shot.
Pace Willisson
pace@blitz.com
next reply other threads:[~1995-08-30 12:11 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
1995-08-30 12:11 Pace [this message]
1995-08-30 15:03 Stephen
1995-09-05 0:47 Ken
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