Chapter 12 Installing and Maintaining

Hardware in a Linux Environment

12.1 - Hardware Terms, Concepts, and Components

12.2 - Hardware Installation, Configuration, and Maintenance

12.3 - Checking and Confirming Hardware Configuration

12.4 - Laptop and Mobile Devices

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.

• When installing RAM, users really do not have to be concerned with compatibility.

• The user can install any RAM from any manufacturer on a Linux system.

Overview of Hardware Components

• 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.

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

• Other x86 compatible chips by other manufacturers such as the AMD Athlon, Duron, and 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.

• The type of video card is only a concern when the X server component is installed.

• The X server provides the GUI.

Miscellaneous Hardware and Components

• Some hardware will require special configuration if it is 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:– With a Tone Generator, 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.

– 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.

• 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 broadcasts, collisions, usage levels, 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

• Internal expansion cards are installed into the system’s motherboard.

• Soundcards, Video Cards, Software modems, SCSI cards, and RAID controllers are all examples of internal expansion cards.

• To view the resource allocations on a Linux system view the /proc/interrupt, /proc/dma, /proc/ioports files.

• Using the cat command with the files above, see what devices are allocated.

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 the device.

• The jumper is a metal cap which is covered by plastic that covers the jumper pins.

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.

Linux Kernel Modules

• The latest distributions of Linux include kernel module loader support.

• One of the latest distributions of Linux is the version of Red Hat Linux that is used in this course.

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

Linux Kernel Modules

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

• The syntax for this command includes adding the name of the module that is being loaded along with some options.

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

Linux Kernel Modules

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

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

• ismod reveals what modules are currently being used and what device is using them, as well as other information.

• ismod also lists the sizes of the modules and the dependency modules.

Checking and Confirming Hardware Configuration

Power Cables

• The first power cable is the one that connects the wall outlet.

• This cable is external and is not necessarily the power cable of concern when installing a hardware device.

• The other type of power cable is internal.

• This cable connects the internal power supply to one of the hardware devices.

Power Cables

• Internal cables enable the devices to send data from one device to another.

• Usually the cables will extend from a controller card or the motherboard to a disk or tape drive, which stores the data.

• The most common form of data cable that is used is ribbon cable.

Power Cables

• When installing SCSI devices, keep in mind some of the data cables will not connect to a device at all because there might be more cables than available devices.

• External Cables are referred to as the cables that connect the computer to the external devices such as keyboards, mice, monitor, printers, scanners, and network connections.

IRQ, DMA, and I/O Settings

• Most hardware, specifically ISA and PCI controller cards, that are inserted into the motherboard use hardware resources located on the motherboard.

• These resources are called the Interrupt Request (IRQ), Direct Memory Access Channel (DMA), and the Input/Output (I/O) Port.

• There are more I/O ports available than DMA channels or IRQs.

EIDE Devices

• EIDE devices are usually hard drives, floppy drives, CD-ROMs, and other types of disk and tape drives.

• The differences are in the data transfer speeds.

• When installing EIDE devices confirm that they are set to the proper Master or Slave setting.

• In Linux, the master drive takes on the lower device letter in its /dev/hdx filename, where x is the device letter.

SCSI Devices

1. Check the SCSI variant.

2. Each SCSI device that is installed needs to be assigned a number, or SCSI ID.

3. Check that there is a terminating device.

4. Check cable quality.5. Check cable length.

BIOS Settings

• The BIOS plays a big role in configuration and installation of hardware.

• Another aspect of the BIOS that will differ from one system to another is the Complementary Metal Oxide Semiconductor (CMOS) setup utility.

• The CMOS is the memory component of the BIOS where low-level configurations and options for certain hardware are saved so that they can be retrieved every time the system is booted.

Diagnosing and Troubleshooting Devices

• In some cases EIDE/ATA devices can produce very slow data transfer speeds in Linux systems.

• One possible reason is the use of wrong drivers.

• The hdparm utility can be used to test disk speeds as well as set several options.

• Read the hdparm man page to find out more information about the complete set of options that can be used with this utility.

SCSI Devices

• In any SCSI chain there needs to be a terminator put in place at each end to keep the signal from continuously bouncing back.

• Some SCSI devices are capable of self-termination by setting the proper jumper or switch.

• SCSI adapters typically have 3 adapters.

• There is one external and two internal adapters.

• The two internal adapters are for wide or narrow internal SCSI adapters.

Peripheral Devices

• Peripheral Devices are devices that connect to the computer through an external or internal port and are controlled by the computer.

• There are several peripheral interfaces which need to be covered to be able to fully diagnose and troubleshoot peripheral device problems. – Floppy, Monitor, Keyboard,

Mouse, Parallel ports, RS-232 serial, USB, cables

Core System Hardware

• The core system hardware refers to the RAM, CPU, and motherboard, the most critical hardware on a system.

• If any of these devices are not working properly or are damaged then they entire system may not work

• In a Linux system, some problems associated with core system hardware do not make themselves known until after the system boots up.

• Another helpful indicator to properly diagnose and troubleshoot core system hardware problems is to identify when the error occurs.

• Does the problem occur right when the system starts up or does the problem come up after the system has been running for a period of time?

Laptop and Mobile Devices

Power Management

• Installing Linux on laptops is another area that requires special attention.

• Linux was not initially designed to run on a system in which things like power management or swapping PC cards was needed.

• The most challenging part of using Linux on a laptop is the installation.

• It can be difficult to get the XFree86 configuration to work properly with the liquid crystal displays (LCDs) that the laptops use.

• The biggest problem to be concerned with when installing Linux on a laptop is getting the GUI to display properly.

PC Card Devices

• A standard for expansion cards that can be easily inserted and removed form the laptop is the PCMCIA card.

• The main problem of using PCMCIA Cards on a Linux system is that these PCMCIA cards are designed to be inserted, or removed at will.

• This forces the driver to be mounted and unmounted whenever the card is inserted and removed from the laptop.

• The PCMCIA card driver package includes the Card Services feature, which helps to smoothly mount and unmount drivers from the kernel in a way that is safe for the system.