Day 4

Understanding Hardware

Partitions

Linux Boot Sequence

Understanding Hardware• Linux requires you to have a passing understanding

of what hardware is in your system

• You may need to know specific brand information about certain devices.– Especially Video hardware

• Monitor

• Video Card

– Hard drives• SCSI/IDE

Inside a typical system• Here is a picture of the inside of a system:

Memory Processor• This system has a Socket 7 CPU (Most common)

– Other alternative is Slot A which is Intel Celeron/PII

Memory• SIMM (Single Inline Memory Module)

– What we have here (Must travel in pairs)

• DIMM (Dual Inline Memory Module)

Video Card• ISA/PCI + Size of video memory

– This is PCI with 8MB Video Ram.

Network Controller• PCI/ISA – Speed/Network Type’

– This is a 3Com905B PCI 10/100 Autosense Ethernet

Hard Drive• IDE/SCSI – Size/Speed

– This is a 7200RPM IDE 4GB Drive

IDE - Master/Slave• IDE drives must be on primary or secondary

channel. On each channel one must be master, other slave. Each drive has jumpers to select.

Other Devices• Sound Card

– Manufacturer

• Monitor– Resolutions– Refresh rate– H Sync/V Sync rates– Color Depth

• Floppy Drive

• CD Rom Drive

• etc.

System BIOS• Basic Input/Output System

• Stores boot up information about your machine.– Revision Date available on bootup.

Telling your system how to boot• BIOS

– Enable HDD controllers– Hard Drive boot order– Enable COMM ports if necessary– Enable Floppy Drives– IRQ Conflicts

• Bootable CD-Rom Disk– Simplifies Install

IRQ• A method for devices to contact the CPU when they

have an interrupt they need to signal.– e.g. Network card has information waiting.

• Each device must have its own IRQ assigned to it– Often Linux will require you to know what IRQ things

are using.– Many BIOS tell you during bootup how things are

configured.– Most OS’s including Linux have a way to indicate IRQ.

• Linux Boot-time• Windows: Hardware profile.

– e.g. look at PS/2 Mouse port, my machine is IRQ 12.

IRQ Cont.• Most devices come with default IRQ.

– Sometimes that conflicts with other device– Many things allow you to change the IRQ

• Usually through some software program

– e.g. 3Com905 Cards.• Default to IRQ 11

• Come with Floppy Disk which includes the necessary software to configure their cards to use some other IRQ.

Dual Booting System• This is a machine which has more than one OS

loaded on its hard drive.– e.g. Windows 95, Linux

• Each time you reboot the system, you will be asked which OS you wish to load.– To switch you must reboot.

Laying out Hard Drive• One way to Dual boot is to have 2 hard drives.

– Drive 1 has Windows 95– Drive 2 has Linux

• In the BIOS select Drive 1 (C:) as the first to boot if you want Windows, select Drive 2 (D:) if you want linux.

• This works great, and prevents you from having problems with one OS accidentally removing the other.

Partitioning Drives• If you only have one physical Drive, you can

achieve almost the same effect by partitioning the drive.– fdisk is a program available on Linux and Dos which

allows you to set up partitions on a drive• However, it is destructive. If there is information you want on

the drive, then you should not use fdisk.

– FIPS, is a program for DOS which allows you to move your partitions around in real time, without data loss.

Partitions• In windows, partitions look like different drives.

– If you have a C and D drive in “My Computer”, you cannot tell if there is 1 or 2 Hard drives in the system from there.

– In linux, partitions get mounted into the file system under directories. Again you cannot tell where on the disks these directories are located.

• e.g. /home

• This may very well be a different partition, or even a different drive.

Typical Linux Layout• Typically linux will have at least 3 partitions

– (Assuming 2GB of available space)

– / • This is usually where the majority of the OS and configuration files are

located.

• This might be approx 500MB.

– /usr• This is where all the users files are located, in general this area is typically

the largest

• This might be approx 1.2GB

– /swap• This is where the OS will swap files when it runs out of memory. Typically

this area must be 2 times as large as physical RAM.

• This might be approx 300MB

Partition Types• Each partition has a type.

• All Linux partitions where data will be stored will be set to Linux Native.

• Your Windows partition will remain FAT32.

• In linux the swap partition must be set to “Linux Swap” type.

Master Boot Record• One partition must be marked as the boot partition,

or active partition.– This partition should contain the master boot record.– For linux, this is called LILO (Linux Loader)– You will configure LILO to boot either Linux or

Windows.