Section 1.2 Introduction to

Personal Computer

Made By : Gagandeep Singh

A+ Hardware

What you learn today

CompTIA A+ 220-701 , Section 1.2Explain the motherboard components, types

and features. - I/O interfaces - Memory Slots - Processor Socket. - Bus Architecture - Bus Slots - Floppy Drives - Hard drives. - BIOS/CMOS/POST

Introduction to Personal ComputerThe outside

- Monitor, Keyboard, Mouse, Computer Case.The inside - Power supply, motherboard, CPU, memory,

cooling fans.Computer operation primer.

The Outside

The Inside

The Inside

SMPS

Motherboard

CPU

LGA VS PGA

Components Socket CPUHeat SinkFAN

Memory (RAM)

System FAN

Floppy Drive

Hard Disk

External Hard Disk

Internal Hard Disk

CMOS /BIOS

OS Booting Sequence Steps

OS Booting Sequence Steps1. First is the POST, this stands for Power On Self Test, for

the computer. The computer power-on self-test (POST) tests the

computer to make sure it meets the necessary system requirements and that all hardware is working properly before starting the remainder of the boot process.

If the computer passes the POST the computer will have a single beep (with some computer BIOS manufacturers it may beep twice) as the computer starts and the computer will continue to start normally. However, if the computer fails the POST, the computer will either not beep at all or will generate a beep code, which tells the user the source of the problem.

The steps of a POST Each time the computer boots up the computer must

past the POST. Below is the common steps a POST performs each time your computer starts.

1. Test the power supply to ensure that it is turned on and that it releases its reset signal.

2. CPU must exit the reset status mode and thereafter be able to execute instructions.

3. BIOS checksum must be valid, meaning that it must be readable.

4. CMOS checksum must be valid, meaning that it must be readable.

The steps of a POSTCPU must be able to read all forms of memory

such as the memory controller, memory bus, and memory module.

6. The first 64KB of memory must be operational and have the capability to be read and written to and from, and capable of containing the POST code.

7. I/O bus / controller must be accessible.8. I/O bus must be able to write / read from the

video subsystem and be able to read all video RAM.

The steps of a POST If the computer does not pass any of the

above tests, your computer will receive an irregular POST. An irregular POST is a beep code that is different from the standard one or two beeps. This could be either no beeps at all or a combination of different beeps indicating what is causing the computer not to past the POST.

Original IBM POST beep codes• 1 short beep - Normal POST - system is OK • 2 short beeps - POST error - error code shown on screen • No beep - Power supply, system board problem,

disconnected CPU, or disconnected speaker, • Continuous beep - Power supply, system board, or keyboard

problem • Repeating short beeps - Power supply or system board

problem or keyboard • 1 long, 1 short beep - System board problem • 1 long, 2 short beeps - Display adapter problem (MDA,

CGA) • 1 long, 3 short beeps - Enhanced Graphics Adapter (EGA) • 3 long beeps - 3270 keyboard card

XP Booting Sequence 2. Once the POST is complete and the BIOS is sure that

everything is working properly, the BIOS will then attempt to read the MBR (Master Boot Record). This is the first sector of the first hard drive (called the Master or HD0). When the MBR takes over it means that Windows is now in control.

3. The MBR looks at the BOOT SECTOR (the first sector of the active partition). That is where NTLDR is located, NTLDR is the BOOT LOADER for Windows XP. NTLDR will allow memory addressing, initiate the file system, read the boot.ini and load the boot menu.

XP Booting Sequence 4. NTLDR has to be in the root of the active partition as do

NTDETECT.COM, BOOT.INI, BOOTSECT.DOS (for multi-OS booting) and NTBOOTDD.SYS (if you have SCSI adapters)Once XP is selected from the Boot Menu, NTLDR will run NTDETECT.COM, BOOT.INI and BOOTSECT.DOS to get the proper OS selected and loaded.

5. The system starts in 16-bit real mode and then moves into 32-bit protected mode. NTLDR will then load NTOSKRNL.EXE and HAL.DLL. Effectively, these two files are windows XP. They must be located in %SystemRoot%System32.

6. NTLDR reads the registry, chooses a hardware profile and authorizes device drivers, in that exact order. At this point NTOSKRNL.EXE takes over. It starts WINLOGON.EXE that in turn starts LSASS.EXE, this is the program that display the Logon screen so that you can logon.

Expansion Slots

RISER CARD

Computer Operation Primer

IPO Cycle INPUT PROCESS OUTPUT

STORAGE