Introduction to Processes (Lecture Notes)

Vocabulary flashcards covering key concepts about processes, CPU, memory hierarchy, and I/O from the lecture notes.

Process

An abstraction of a program in execution; created by the OS when a program runs.

Program

A lifeless set of instructions stored on disk that becomes a process when executed.

Main Memory

Store for instructions and data of the running process; CPU cannot access disk directly and uses caching to hide latency.

CPU (Central Processing Unit)

The component that executes instructions; includes PC, IR, general purpose registers, ALU, CCR, and SP.

Program Counter (PC)

Stores the address of the instruction currently being executed.

Instruction Register (IR)

Stores the instruction currently being executed.

General Purpose Registers

Temporarily store operands for operations.

Arithmetic Logic Unit (ALU)

Performs arithmetic and logical operations on data in registers.

Condition Code Register (CCR) / Status/Flag Register

Stores the result of the last operation and status information for subsequent Instructions.

Stack Pointer (SP)

Supports function calls by pointing to the top of the stack.

Cache

Small, fast memory to hide latency between CPU and main memory; has multiple levels and types.

L1/L2/L3/L4 Cache

Levels of cache in a cache hierarchy that speed memory access; each level differs in size and speed.

Latency

Time delay for memory operations; a key factor in CPU-memory performance.

Main Memory Reference

Access to main memory; typically around 100 ns latency.

DRAM (Dynamic RAM)

A type of main memory referenced in memory-performance discussions.

Processor-Memory Performance Gap

The speed gap between a fast CPU and comparatively slower memory.

I/O Devices

Devices for interacting with the outside world (keyboard, display, mouse, disk, printer, etc.).

Latency Hiding

Techniques to mask the latency of slower I/O devices relative to memory/CPU.

Multiprogramming

A technique to keep the CPU busy by running multiple programs (processes) in memory.