This document provides an overview of the key components of a personal computer, including the CPU, RAM, motherboard, power supply, storage devices, and input/output devices. It also describes common internal and external busses that connect these components. Finally, it explains the differences between common networking devices like hubs, bridges, switches, and routers in terms of their layer of operation, addressing, and use cases.

1.  
PC Repair and Troubleshooting

2.  Hardware
 Software

3.  Motherboard
 Power Supply
 Drives
 IO Devices
 Communication Devices
 Storage Devices

4.  CPU - performs most of the calculations which enable a computer to function
 Heat Sink and Fan – cools the CPU
 RAM - stores resident part of the current running OS and all running processes
 BIOS
o Boot firmware
• Fixed / ussually small programs
o Power Management
 Chipset - provides the supporting interfaces between the CPU and the various buses and
external components. This chipset determines, to an extent, the features and capabilities of
the motherboard.
 Internal Busses - connect the CPU to various internal components and to expansion cards
for graphics and sound
o PCI
o SATA
o ATA
 External Busses Controllers - support ports for external peripherals.
o USB
o IEEE 1394 interface - serial bus interface standard for high-speed communications and
isochronous real-time data transfer, frequently used by personal computers, as well as in digital
audio, digital video, automotive, and aeronautics applications.
o Small Computer System Interconnect - set of standards for physically connecting and transferring
data between computers and peripheral devices

6.  converts alternating current (AC) electric power to low-
voltage DC power for the internal components of the
computer

7.  CD / DVD / HD DVD / Blu Ray
 Floppy
 HDD
 USB Flash
 Tape

8.  Keyboard
 Mouse
 Monitor
 Webcam
 Microphone
 Speaker
 Headset
 Printer
 Scanner

9.  Primary
 Secondary
 Tertiary
o Disks
• Magneto optic disks
• Optical disks
• WORM
o Tapes
o USB Flash
o External HDD

10.  Repeater
 NIC
 Modem
 Hub
 Bridge
 Switch
 Router

11. HUB BRIDGE SWITCH ROUTER
Physical Layer Data Link Layer Data Link Layer Network Layer
Bus Backbone MAC Address MAC Address IP Address
Transmits to all ports Transmits only if on Transmits to a Transmits to a
the other side designated host designated host
Don’t analyse traffic Allow/Disallow traffic Manages traffic Avoids traffic
1 Collision & Every segment has a Every port has Separates Broadcast
Broadcast Domain collision domain and Collision Domain and Domain
Broadcast domain as a Broadcast Domain as
whole a whole
Same Subnet Same Subnet Same Subnet Different Subnets
used on small used to connect large networks use most common home
networks where the different network switches rather than use for routers is to
amount of data going segments hubs to connect share a broadband
across the network is computers within the internet connection.
never very high same subnet
Creates a network Connects Network Connects Network Connects Network
segment Segments Segments