Chapter 4 Installing and Maintaining

Hardware in a Linux Environment

Part 1

Overview

1. Hardware Terms, Concepts, and Components2. Hardware Installation, Configuration, and Maintenance

Hardware Terms, Concepts and Components

Overview of Hardware Components

The motherboard is the central component, which allows every other hardware device in the system to run. Like the central processing unit (CPU), if the motherboard fails, so does the system.

Choosing the correct motherboard for a Linux system is a very important step because it determines what type of CPU and RAM users must install.

Certain distributions can only use certain processors, which must be supported by the motherboard .

Overview of Hardware Components

The user can install any RAM from any manufacturer but must be the correct type for the motherboard he selects. .

Hardware will include a small capacity hard drive, a CD-ROM drive, and an inexpensive video card if the system will only be used for basic word processing, e-mail, and Internet access.

Central Processing Unit (CPU)

Originally, Linux was developed for Intel 80x86 which known as the x86 processor.

Linux was developed on the 386 system and can still run on that system today and is also compatible with Intel subsequent family of processors like the 486 and entire class of Pentium class processors.

Other x86 compatible chips by other manufacturers such as the Athlon, Duron, and AMD K6 processors are also compatible with Linux.

Video Hardware

Selecting and configuring Video hardware is a complicated task.

Linux systems that are only to be used as servers do not necessarily need to be concerned with what video card is installed.

When selecting a video card you have to check:

How much RAM the video card has.

If it’s compatible with the X server being used.

Miscellaneous Hardware and Components

Some hardware will require special configuration if they are installed in a Linux system.

The following devices may require special drivers or configurations before they operate properly with Linux: USB Devices Sound Cards Video Capture Cards Internal Modems

Hardware Monitoring Devices

Some devices that can be useful in troubleshooting network problems include the following: The ’fox‘ portion can be

attached to one end of the cable, and a tone is generated. A locator, or the ’hound‘, at the other end receives the tone. This shows that the correct cable has been identified.

The crossover cable is used to connect two computers without going through a hub.

Hardware Monitoring Devices

With a Time domain reflectometer (TDR) a sonar-type pulse is sent through the cable. Then, the pulse is measured to locate shorts or breaks in the cable.

The volt-ohm meter, or voltmeter, is used to measure electronic pulses through cable and to determine if there are shorts or breaks in the cable.

Hardware Monitoring Devices

A cable tester is used to detect breaks and shorts.

An oscilloscope is used in electronics calibration. It is also used to measure how much signal voltage

passes through a cable over a set period of time. A LAN meter can check for collisions and errors

on Ethernet and Token Ring LANs.

Hardware Installation, Configuration, and Maintenance

Locating Hardware Drivers for Linux

There are several possible sources of hardware drivers for a Linux system.

In a Linux system, the kernel will serve as the interface between the operating system, which is the software, and the hardware.

Most Linux drivers are either located in the Linux kernel initially, or added to it in some way.

Some hardware such as printers, scanners, and video card drivers are not located in the kernel.

These devices reside externally in non-kernel software.

Configuring Hardware in a Linux System

Soundcards, Video Cards, Software modems and SCSI cards are all examples of internal expansion cards that installed into the motherboard.

Each device requires at least one IRQ, DMA, and I/O port assignment. If too many devices are installed, resource allocation conflicts may occur.

To view the resource allocations use cat command to view the /proc/interrupt, /proc/dma, /proc/ioports files.

Configuring Hardware in a Linux System

If using a GUI interface like KDE for example, view the resource allocations by using the GUI Control Center tool.

Set the proper jumpers for devices such as floppy drives and hard drives.

The jumper is a metal cap covered by plastic used to covers the drive pins.

Most hardware devices use plug-and-play (PnP) technology instead of jumpers. PNP devices controlled by isapnp program and through an ISA configuration in kernel.

The 2.4.X Linux kernel includes ISA PnP support that does not require isapnp program.

Configuring Hardware in a Linux System

The final step of configuring hardware on a Linux system is being able to load the appropriate drivers and setting the correct options related to the driver.

The two ways that options can be set for drivers are through kernel options and module options.

To set driver options through the kernel, edit the /etc/lilo.conf, configuration file which passes these options to the kernel.

Linux Kernel Modules

The latest distributions of Linux include kernel module loader support.

Kernel module loader support means that the kernel has the ability to load and unload drivers as it needs them.

When a device needs to be used and the kernel cannot automatically load or unload modules for it, other programs will need to be used.

These programs are insmod, modprobe, rmmod and lsmod program.

Linux Kernel Modules

The insmod program, is used to insert a single module into the kernel.

The modprobe program, reduces this administrative overhead by automatically loading any dependencies a module has.

The rmmod program, can be used to remove drivers or modules.

The modprobe program with the -r or --remove option will also remove modules.

lsmod shows what modules are currently being used and what device is using them, as well as other information.

lsmod also lists the sizes of the modules and the dependency modules.