Computer Architecture Overview

Study Notes

Input devices such as keyboards, mice, and scanners enter data into the computer
Internal application programs can also input data in the form of programmed instructions.

The CPU sends processed results to output units such as monitors, printers, and speakers.

Fetch: The CPU fetches instructions and data from RAM using a program counter that holds addresses of instructions.
Decode: The CPU decodes instructions for understanding. The instructions are converted into signals that the CPU can understand and execute.
Execute: The CPU executes decoded instructions, including arithmetic, logical, and data transfer operations.
Storage: Results are stored in memory or are sent to output devices after execution. Processed data is stored in memory for future use.
Output: The CPU outputs the processed data to the user via output devices. Results can be text, printed reports, or sounds.

Random Access Memory (RAM): Stores data and instructions that the processor needs to perform operations quickly.
- Stable Random Access Memory (SRAM): Used in cache memory, characterized by its high speed but is expensive.
- Dynamic Random Access Memory (DRAM): Used in main memory, needs constant updates with data.
Read Only Memory (ROM): Stores the basic programs that the computer needs to start up.
- PROM: Programmable ROM.
- EPROM: Erasable Programmable ROM.
- EEPROM: Electrically Erasable Programmable ROM.
Cache Memory: Speed up access to frequently accessed data and reduce access time.

Buses: Paths or communication lines that connect different computer components. They act as means of transmitting data and signals between different components.
Data Bus: Transfers data between the CPU and other components. Can be 8, 16, 32, or 64 bits wide. The wider the bus, the more data can be transferred at one time.
Address Bus: Transfers memory addresses used to locate data in memory. The number of wires on the address bus determines the amount of memory the computer can access.
Control Bus: Transfers control signals between the CPU and other components. Includes signals such as read and write signals, timing signals, and interrupt signals.

Facilitating Communication: Enable communication between different components.
Organizing Operations: Help organize operations.
Increasing Performance: Contribute to increasing computer performance by providing fast and efficient paths.