Hardware and OS basics

Computer architecture

Main hardware components

1. CPU
2. memory
3. storage
4. input/output
5. motherboard

CPU

• hardware component that runs programs

Control Unit

• Retrieves and decodes program instructions
• coordinate computer operations

Data path

• Arithmetic logic unit(ALU) Performs basic math
• registers

ALU

• Arithmetic and logic

Registers

• Memory slots in the processor that store data for fast lookup *General and special

CPU Cycle

• Fetch, Decode, Execute

Memory

Memory hierarchy

• CPU

• Registers
• L1 cache
• L2 cache

• L3 cache (on MB)
• RAM (on MB)
• Disk Storage (HD)

Registers

• High speed storage inside processor
• Temporally hold data as instructions

Caches

• Stores frequently accessed data
• L1: Part of the processor
• L2: Near(but not on ) processor
• L3: father away than L2, perhaps not on the motherboard

Main Memory

• Holds program data and instructions
• Volatile - erased when the program terminates or computer is turned off
• also called RAM

Clocks

Synchronizes the actions of a system

• Master clock
• Actions happen on clock ticks
• Shorter clock cycles mean faster performance

Buses

• allows computer components to communicate
• only one system can use a bus at a time
• Requires protocols
• Synchronous vs. Asynchronous
• Point-to-point vs Multipoint

Secondary storage

• Holds data when program's are not running or system is powered off

Other important devices

Input devices

• send information from outside to computer

Output devices

• sends out put from computer to devices

Motherboard

Connects all components

• Processor
• RAM Slots
• PCIe Slots
• I/O

• Network
• Sound
• USB
• Hard Drive
• PS2