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Linux+ Guide to Linux Certification, Second Edition

Chapter 7Advanced Installation

Linux+ Guide to Linux Certification, 2e 2

Objectives

• Describe the types and structure of SCSI devices

• Identify default IRQs, I/O addresses, and DMAs

• Explain how Plug-and-Play can be used to assign configuration to peripheral devices

• Explain how APM and ACPI can be used to control power to peripheral devices


Objectives (continued)

• Outline the steps used to install Linux from source files on a DVD, hard disk, or network server

• Understand methods used to automate the Linux installation

• Install Red Hat Fedora Linux using a kickstart file

• Troubleshoot the installation process


Advanced Hardware Configuration: SCSI Hard Disk Drive Configuration

• Terminator: Prevents signals from bouncing back and forth on a cable

• SCSI ID: Uniquely identifies devices attached to a SCSI controller– Target ID– Identifies priority

• Logical Unit Number (LUN): Unique ID for each device attached to a node in a SCSI chain



(continued)

Figure 7-1: Connecting SCSI devices



(continued)

Table 7-1: Common SCSI standards



(continued)

Figure 7-2: A 50-pin Centronics SCSI connector

Figure 7-3: A 50-pin LPT SCSI connector



(continued)

Figure 7-4: A 68-pin LPT SCSI connector


Mainboard Flow Control: IRQs, DMAs, and I/O Addresses

• IRQs: Method for peripheral devices to share processor time– Prioritize simultaneous service requests

• Polling: Processor polls devices to determine tasks to be run– Difficult to prioritize

• Interruption: Processor interrupted by devices when resources needed– Prioritize via IRQ


Mainboard Flow Control: IRQs, DMAs, and I/O Addresses (continued)

Figure 7-5: IRQ priorities



Table 7-2: Default IRQ assignments



• I/O address: Identifies working space in RAM for peripheral devices

• DMA: Allows devices direct physical memory access via unique channels– Improves system performance



Table 7-3: Default I/O address assignments



Table 7-4: Default DMA assignments


Plug-and-Play

• PnP: Automatically assigns configuration information to devices– IRQs, I/O addresses, DMAs– Uses BIOS information to avoid conflicts

• Complimentary Metal Oxide Semiconductor (CMOS): Memory on mainboard used to store configuration information for boot process


APM and ACPI

• APM: Shuts off power to peripheral components as needed– Configured in BIOS

• Advanced Configuration and Power Interface (ACPI): Configures peripheral’s power setting from OS– Monitor CPU temperature and battery power– Standby mode and sleep mode

• Linux ACPI Client: Utility used to view ACPI settings


RAID Configuration

• Fault tolerant: Device exhibiting minimum downtime after failure

• Redundant Array of Inexpensive Disks (RAID): Combines several HDDs’ storage space– Hardware- or software-based– Seven raid configurations


RAID Configuration (continued)

• Spanning: Two HDDs seen as one volume– RAID level 0, not fault tolerant

• Disk striping: Write separate information to different HDDs– RAID level 0, not fault tolerant– Decreases read/write time

• Disk mirroring: Two identical hard disks– RAID level 1, fault tolerant



• Disk striping with parity: Write separate information to HDDs and maintain parity information– RAID level 5, fault tolerant– Parity bits indicate what data is where

• Can be used to re-generate data when HDD fails

– Requires three HDDs minimum– Most common RAID configuration



Figure 7-6: Organization of data on RAID level 5


Installation Methods

• International Standards Organization (ISO) image: Large file containing exact copy of contents of a CD-ROM or DVD

• CD-ROM is the most common and easiest method for installing Linux

• Other methods for installing Linux – DVD– Network server– Local hard disk


DVD Installation

• Similar to CD-ROM installation

• Only one DVD required, as opposed to multiple CD-ROMs


Hard Disk Installation

• May install Linux directly from ISO images on hard disk– Must have sufficient free space outside partition

containing ISO images

• Create installation startup CD-ROM or bootable USB flash memory drive– Boot from this to start installation

• Installation will be text-based


Hard Disk Installation (continued)

Figure 7-7: Installation welcome screen



Figure 7-8: Language selection screen



Figure 7-9: Keyboard selection screen



Figure 7-10: Selecting an installation method



Figure 7-11: Specifying source file location for a hard disk-based installation


Network-Based Installations

• Requires installation startup CD-ROM or bootable USB flash memory drive– Contains NIC drivers and programs allowing

connection to server• Installation via one of following protocols:

– Network File System (NFS)– File Transfer Protocol (FTP)– Hypertext Transfer Protocol (HTTP)

• Must configure network settings


Network-Based Installations (continued)

Figure 7-12: Configuring local network settings



Figure 7-13:Specifying source file location for an NFS-based installation



Figure 7-14: Specifying source file location for an FTP-based installation



Figure 7-15: Specifying source file location for an HTTP-based installation


Automating Linux Installations

• Deploy several Linux servers and workstations requiring same configuration

• Disk imaging software: Duplicates HDD contents from one computer to another– e.g., Symantec Ghost– Typically loaded from boot floppy disk– Copy whole partitions or HDDs to other HDDs

• Locally or across network


Automating Linux Installations (continued)

Figure 7-16: Symantec Ghost



• Kickstart file: Automated installation script– Specifies normal OS installation choices– ks.cfg

• Kickstart Configuration: Configure a new kickstart file

• To use ks.cfg: – Format floppy with ext2, copy ks.cfg to it– Boot from installation startup CD-ROM– At welcome screen, specify ks.cfg file



Figure 7-17: The Kickstart Configurator


Troubleshooting Installation

• Computers typically have different BIOS configurations– Installing on different computers is rarely the same

• Problems primarily related to hardware support or configuration– Typically fixed by changing hardware configuration


Problems Starting the Installation

• Check BIOS boot order

• Check BIOS for reserved peripheral configurations (IRQ, I/O addresses, DMA)


Problems During Installation

• For graphical installation, video card must be detected – Appropriate drivers must be loaded– Video card may not be supported by mode and

resolution of graphical installation• Use Linux nofb or linux lowres installation

• Mouse does not work– Use text-based installation


Problems During Installation (continued)

• Installation freezes– Disable PnP support in BIOS prior to installation

• Installation ends abnormally – “fatal signal 11” error displayed– Could be problem with RAM– Often fixed by turning off CPU cache memory or

increasing number of wait states in the BIOS– Could also be RAM or CPU voltage issue


Problems During Installation (continued)

• Other failure causes include bad memory chips, an AMD K6 processor, laptop power management conflicts, overclocked CPUs

• Overclocked: Running a processor at a higher speed than it is rated for– May lead to increased performance– Produces more heat on processor

• May result in computer crashes


Problems After Installation

• May have problems if installation program did not detect computer hardware properly or certain programs were not installed

• Installation log file: Records actions that occur or fail during installation– /root/install.log: Lists packages installed– /root/install.log.syslog: Lists all system events that

occurred during installation


Problems After Installation (continued)

• To verify hardware settings, examine contents of /proc directory or boot-up log files

• To view hardware detected at boot time, use dmesg command



Table 7-5: Files commonly found in the /proc directory



Table 7-5 (continued): Files commonly found in the /proc directory