Hardware Problems

Okay, by this stage in your computer technologies career you’re already familiar with the usual litany:

  • Check out any POST errors you get,
  • Make sure SCSI drives are terminate,
  • Make sure it’s plugged in,
  • Make sure it’s turned on,
  • etc. etc. etc. ….

Things get trickier fast once you reach the stage of checking IRQ and I/O addresses. At this point you must remember one thing:

Log files are the ultimate resource for hardware diagnosis.


Take a good detailed look at what happened during the last boot. Command:

dmesg > lastboot.txt


less lastboot.txt

This gives you a good view into the boot process, in agonizing detail.

You may also have information (or you may not) in /var/log/boot.log. Check it and /var/log/messages, the main system log file.

less /var/log/boot.log

less /var/log/messages


Modems and serial ports look like the same thing to your Linux system. Thus they can sometimes fight for the same IRQs and I/O addresses. Use the setserial command to set IRQ, I/O, and port speed:

setserial /dev/ttyS0 irq 11 port 0x03f8

and check the results:

setserial /dev/ttyS0

The relevant keywords are:

port n Sets I/O address
irq n Sets IRQ to n
auto_irq Tries to detect IRQ setting
spd_hi Sets serial port speed to 56KB/s
spd_vhi Sets serial port speed to 115KB/s
spd_normal Sets serial port speed to 38.4KB/s