LPI 101 Ch03 Hardware

8/9/2019 LPI 101 Ch03 Hardware

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SAIGONLAB 83 Nguyn Th Nh, P9, Q.Tn Bnh, Tp. HCM LPI 102 1

Chapter 3

Hardware


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Objectives

Describe a system boot procedure

Describe the POST procedure

Describe the BIOS/CMOS

Identify the different drive types (ATAPISCSI, )

Define and identify hot swapable hardware

Identify the different types of address

Identify the different types of ports

Identify the different types of channelcategories


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Hardware

While Linux supports hardware and most

device manufacturers provide Linux drivers,

some hardwares does not work with Linux

(e.g Winmodems). When youre going to

install Linux, or add devices to Linux machine,

check a hardware compatibility list ( HCL ) at :

http://www.tldp.org/HOWTO/Hardware-HOWTO/index.html

If you device isnt listed on HCL, then check

the manufacturers website to see if Linux

drivers are available.


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System Boot Procedure

1. First, the internal power supply turns on. It

takes a bit of time to generate enough power

for the rest system

2.W

hen there is sufficient power, the processoris ready to execute and it looks to the BIOS

ROM for instructions

3. Next, the BIOS performs the Power-On Self-

Test, or POST. If there are no problems foundduring, then computer beeps once and

continues with the boot process


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4. After POST, the BIOS looks for and executesthe video card's BIOS program, and initializes

the video card

5. When the video card is initialized, the BIOS

looks for any other device ROMs that have

BIOSes, such as ITE/ATA hard drives

6. Now the BIOS displays the startup screen

7. BIOS continues toperform more tests, suchas the memory count-up test. Any errors

encountered at this point in the process will

usually generate an error message on the

screen


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8. Next, the BIOS takes more inventory of the hardware

on the system. It is at this stage that modern BIOSes

initiate automatic settings

9. If the Plug and Play (PnP) standard is supported hy the

BIOS, then PnP devices are configuredat this stage10.Now the BIOS begins tosearch for a drive to boot.The

order depends on the boot sequence BIOS setting

11.When the target boot drive is identified, the BIOS looks

for the boot information to start the OS. Once it finds ,

the BIOSstarts the process of booting the OS, using

the information in the boot sector


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POST ( Power-On Self Test )

Before the BIOS initiates the actual boot

sequence, a built-in diagnostic program

called POST checks the hardware and verifies

that essential components are present and

functioning. After verifying the components,

it performs a memory test as the actual boot

process begins

If everything checks out correctly, BIOSemits a beep, otherwise BIOS will emit a

series of beeps


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BIOS and CMOS

Thesettings for the BIOS arestoredin theComplementary Metal Oxide Semiconductor,

or CMOS. The information includes : time,

type and speed of the CPU, hard drive

parameters, and the amount of RAM in the

computer,

A small batteryin the computer powers the

CMOS memory setting. so the settings are

retained when the computer is shut down. In

the event of a battery failure the settings are

usually lost, even password for CMOS

protection


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Floppy Drives

The controller for floppy drives have 34 wires

and 3 connectors :one connect to

motherboard, other two are reserved for

floppy drives fd0, fd1


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IDE Drives

Most hard drives and CD drives are IDE (

Integrated Drive Electronics) and conform to

AT Attachment Packet Interface (ATAPI). IDE

devices use a 40-pin ribbon to connect to

ATAPI controllers

Most PCs have 2 ATAPI controllers: aprimary

and asecondary. Each controller can connect

to two different IDE drives with one drivedesignated as the master drive and the other

as the slave drive


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IDE Drives

To optimize your hardware set up with IDE

devices, it is best to have only one hard drive

and one CD drive set up in the primary and

secondary master positions: the hard drive

as hda and the CD as hdc


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SCSI (Small Computer SystemInterface)

Designed to be a high-level, expandable, high-

performance interface, SCSI is usually found in

servers and other high-end computers

Since SCSI's creation in 1979, multiple forms of SCSI

standards have been developed : SCSI-1.SCSI-2, andSCSI-3. They all have two things in common:

All SCSI devices are controlled by a host adapter

All SCSI devices are connected in series, with the

last device using a terminator indicating that it is

the final device in the chain


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Types of SCSI and Characteristics

SCSI-1 8-bit 50 5MBps

SCSI-2 (Fast SCSI) 8-bit 50 10MBps

SCSI-2 (Wide SCSI) 16-bit 68 20MBps

SCSI-3 (Ultra Wide SCSI) 16-bit 68 40MBps

SCSI-3 (Ultra2 Wide SCSI) 16-bit 68 80MBps

SCSI Type Bus Wires Data Transfer


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SCSI BIOS

Like the BIOS, there is usually a key

configuration to enter the SCSI BIOS menu at

boot time. In this menu you can configure

boot sequences, controller SCSI addresses,

SCSI bus speed, onboard termination, and

more.


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PERIPHERAL DEVICES: AGP, ISA AND PCI

Three slots for installation peripherals :

AGP : Accelerated Graphics Port, is a common option

for video cards. AGP video cards uses computers

RAM memory to boost performance, runs at 66Mhz

or higher ISA : Industry Standard Architecture, is the oldest

standard for peripheral cards, runs at 8.33MHz

PCI : Peripheral Component Interconnect, hardware

does not communicate directly with the CPU. Using

DMA (direct memory access) channels instead, PCI

hardware communicates directly with other

components in the computer. The PCI bus runs at

33MHz.


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HOT SWAPPABLE HARDWARE

Hot swappable devices are peripherals that

can be added or removed from a computer

without having to reboot the machine.

Three types of hot swapable devices: USB - Universal Serial Bus

IEEE 1394 Institute for Electrical and

Electronics Engineers 1394

PCMCIA Personal Computer Memory Card


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USB

USB was developed in 1996 but was not

incorporated into Linux kernel until the

realease of 2.4 kernel

USB data transfer : 1.5MBps ( USB1.x ),

60MBps (USB 2.0)

Support for USB 2.0 is planed for the 2.6

Linux kernel


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Other Peripherals

On the back of standard PCs there are ports

for specific peripherals:

PS/2 : Used for mice and keyboards

COM : COM is short for serialcommunications port. Older mice and

modems use this port

LPT : The LPT ports are used by printers


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Channels

When configuring a PC, the most common

cause of devices not working are channel

conflicts. Its important to assign only one

device to a channel

Channel can be categorized :

Interrupt Requests (IRQ)

Input/output (I/O) addresses

Direct memory access (DMA)

Communication (COM) ports

Printer ports (LPT)


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IRQ

Interrupt requests, or IRQs, are what allows

devices to send requests to the CPU for servic

Modern computer has 16 IRQs, numbered 0-

15, lower numbers having a higher priority

While most devices can NOT share IRQs, some

types of hard drive and USB controller can


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IRQsandtheirdefaultdevices

0 System Timer 8 Realtimeclock (inCMOS)

1 Keyboard 9 Varies

2 CascadefromIRQs8-15 10 Varies

3 COM2 orCOM4 11 Varies

4 COM1 orCOM3 12 PS/2Mouse

5 Somesoundcards orsecondLPT 13 Mathcoprocessor

6 Floppy diskcontroller 14 Primary ATAPIcontroller

7 FirstLPT 15 Secondary ATAPIcontroller


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I/O Address

Devices on a PC require that they have a few

bytes of RAM located at one or more

input/output (I/O)addresses. The information

stored within these addresses are shared with

the rest of the system.

I/O Addresses are shown in hexadecimal

notation. For example, the I/O address

associated with COM2 is 02f8


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DMA

DMA are used primarily to transfer information to and

from memory without the main CPU handling each bit.

Most PCs have eightDMA channels and are typically

used by floppy drives, tape drives, and some sound

cards


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COM Ports

COM ports are also known asserialports. COM ports are

associated with specific IRQ and I/O addresses :

Port IRQ LinuxDesignation I/Oaddress

COM1 4 ttyS0 3f8

COM2 3 ttyS1 2f8

COM3 4 ttyS2 3e8

COM4 3 ttyS3 2e8


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Printer Ports (LPT)

Most PCs have one physical printer port,

though you can get an adapter to set up a

second LPT if needed.The IRQs and I/O

addresses for LPTI and LPT2 are as follows:

Table 3.6 Default IRQ and I/O Addresses for LPT ports

Port IRQ LinuxDesignation I/OAddress

LPT1 7 lp0 378

LPT2 5 lp1 278


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SCSI Device Numbering

For SCSI, the type of SCSI bus determines the

number of SCSI devices you can have on your

computer

Each device is associated with a number that

determines the priority in accessing the SCSI

bus ( 0-7 , 0-15 )

SCSI ID 7 is reservedfor the SCSI host

adapter since 7 has the highest priority. SCSI numbering, going from highestto lowest

in priority, is as follows: 7, 6, 5, 4, 3, 2, 1,0,

15, 14, 13, 12, 11, 10,9,8


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Summary

Describe a system boot procedure

Describe the POST procedure

Describe the BIOS/CMOS

Identify the different drive types (ATAPISCSI, )

Define and identify hot swapable hardware

Identify the different types of address

Identify the different types of ports

Identify the different types of channelcategories

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LPI 101 Ch03 Hardware