Floppy-Disk blocked signal problem.
From: Richard B. Johnson
Date: Fri Nov 07 2003 - 18:10:42 EST
Linux 2.4.22 has a major problem when reading the floppy disk.
Signal delivery is so delayed that many are lost. This program
will show that one can't count upon getting even one signal per
second reliably delivered when a floppy is being read!
This was first discovered when trying to ise ITIMER_REAL with
100 ticks/second. Lucky if we got one. Then I found that even
trying to get one tick/second was a problem:
#define BUF_LEN 0x10000
void handler(int unused)
fprintf(stderr, "%08x\n", time(NULL));
if((fd = open("/dev/fd0", O_RDONLY)) == -1)
if((buf = malloc(BUF_LEN * sizeof(char))) == NULL)
fprintf(stderr, "No memory\n");
while(read(fd, buf, BUF_LEN) == BUF_LEN)
Script started on Fri Nov 7 12:07:02 2003
Script done on Fri Nov 7 12:07:59 2003
Penguin : Linux version 2.4.22 on an i686 machine (797.90 BogoMips).
Note 96.31% of all statistics are fiction.
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