Section 33.4. Hardware (Topic 2.204)

33.4. Hardware (Topic 2.204)

33.4.1. Review Questions

1. You have just updated the /etc/raidtab file. What command should you run to create the RAID array?

2. What file can you read to determine which USB devices have been recognized on your system?

3. What three things can you do with the modprobe command?

4. You have just added a new device but do not know the interrupt that this device is using. What file in the /proc directory can you query?

5. A coworker has just added a new CD/DVD-RW drive via USB. You wish to verify its speed. What command allows you to do this?

33.4.2. Answers

1. mkraid.

2. /proc/bus/usb/devices.

3. You can add modules, delete modules, and list the modules that can be run on the system.

4. /proc/interrupts.

5. syctl -a.

33.4.3. Exercises

1. View the /proc/interrupts file and compare it to the output of the lspci -vv command. Notice that you can get the same IRQ information from both. However, the lspci -vv command gives you much more information about the devices themselves, as long as they are PCI based.

2. Use the hdparm command to read the parameters on your devices. For example, if you have an IDE drive as your first disk, issue the following command as root:

    hdparm /dev/hda 

   
   

   Review the output. Is DMA turned on or off? Be careful when enabling or disabling any settings. Enable features using hdparm only if you are sure your hard disk supports them. Similarly, disabling features might severely impact disk performance. If you wish, use the sysctl command to discover the speed of your CD-ROM. Then use hdparm's -E option to specify a lower speed. Return the speed back to its default using the -E option again.

3. As root, use the tune2fs command to list the filesystem parameters for your first hard drive:

    tune2fs -l /dev/hda 

   
   

4. Use the -c option to specify how many times the system must be mounted before fsck is automatically run. Use the -C option to tell the filesystem how many times the drive has been mounted. Be careful when adjusting any other parameters, as doing so may cause you to lose data.

5. Use the sysctl command to view the settings for the following devices:

   • Ethernet card (wireless or standard)

   • CD-ROM drive

   • Whether or not the system is configured to ignore all ICMP packets

   • The kernel version and release

6. If the setserial command is installed, use it to determine the default settings for your serial devices. Then adjust those settings.

7. If you have Xfree86 installed, use the following options to the XFree86 command:

   • -version

   • -scanpci

   Then toggle between resolutions, if your X server supports them. Pressing Ctrl-Alt-Minus (using the minus key on the keyboard) lowers the resolution. Pressing Ctrl-Alt-Plus (using the plus key on the keyboard) increases the resolution. If multiple resolutions do not exist, use XF86config to create them.