Computer Science O'Clock Unit 1

Hardware

The non perihperal physical components of a computer, such as the motherboard, CPU, RAM, and hard drive.

Software

Programs and applications that run on the computer, like operating systems (Windows) and browsers (Chrome).

Peripheral

External devices that communicate with the computer, like a mouse, keyboard, or printer, speakers ect.

Human Resources

People who are used or could be used in an organization, business, or economy.

CPU (Central Processing Unit)

Works as part of the process phase. The brain of the computer, responsible for executing instructions. retrieves and saves data to and from the storage. Can only retrieve data from an input or primary memory.

CU (Control Unit)

Part of the CPU that manages the execution of instructions by directing other components. Controls the retrieval of instructions from the primary memory and the sequence of execution.

ALU (Arithmetic Logic Unit)

Part of the CPU. Performs all the basic arithmetic, logical, or input/output operations. The CU gives the ALU the data and the instructions on how to process that data.

MAR (Memory Address Register)

Holds the memory address of data that needs to be accessed by the CPU. Communicates the primary memory through the memory bus. Holds the memory address so the ALU knows where to find the data in the primary memory.

MDR (Memory Data Register)

Temporarily holds data that is being transferred to or from memory. Communicates to the primary memory through the Data Bus. Holds the corresponding data to the location that the MAR is holding.

Input, Process, Storage, Output Model

A conceptual model where data is inputted, processed, stored, and then outputted by a system.

Address Bus

A communication system that transfers the location (address) of data in memory.

Data Bus

Transfers actual data between the CPU and memory.

RAM (Random Access Memory)

Volatile memory used for temporary storage while programs are running. The random access part means that it can be accessed in any order.

SRAM (Static RAM)

Fast, expensive memory used in caches, doesn't need constant refreshing.

DRAM (Dynamic RAM)

Slower, cheaper main memory that needs to be constantly refreshed. Makes up the bulk of RAM.

ROM (Read Only Memory)

Non-volatile memory that stores essential startup instructions for the computer.

Cache memory

Very fast memory that stores frequently accessed data for quick retrieval by the CPU.

L1 / L2 / L3 Cache

Levels of cache memory; L1 is the fastest and smallest, closest to the CPU.

Primary Memory

Memory that is directly accessible by the CPU, like RAM and ROM.

Secondary Memory

Non-volatile memory, such as hard drives and SSDs, used for long-term storage.

Machine Instruction Cycle

The process the CPU follows to execute an instruction, which go in order of fetch, decode, execute, and store steps.

Fetch

The CPU retrieves an instruction from memory.

Decode

The CPU interprets the instruction.

Execute

The CPU performs the instruction.

Store

The CPU writes the result back to memory.