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Computer Architecture
Knowledge Summary
The Five Major Components of a Computer
- Arithmetic Logic Unit (ALU): performs arithmetic and logical operations
- Control Unit (CU): directs and coordinates all parts of the computer
- Memory: stores data and programs
- Input Devices: convert external information into a form the computer can recognize, such as keyboards and mice
- Output Devices: convert the computer's processing results into a form humans can recognize, such as monitors and printers
CPU = ALU + CU
Memory Hierarchy
| Level | Type | Speed | Capacity | Characteristics |
|---|---|---|---|---|
| Level 1 | Registers | Fastest | Smallest | Inside the CPU |
| Level 2 | Cache | Very fast | Relatively small | SRAM |
| Level 3 | Main memory (RAM) | Fast | Medium | Data is lost when power is off |
| Level 4 | Secondary storage (HDD/SSD) | Slow | Large | Data is retained without power |
Frequently Tested Unit Conversions
- 1 Byte = 8 bit
- 1 KB = 1024 B
- 1 MB = 1024 KB
- 1 GB = 1024 MB
- 1 TB = 1024 GB
Buses
- Data bus: transfers data
- Address bus: transfers address signals; an n-bit address bus can address 2^n memory units
- Control bus: transfers control signals