CSC 005 Lecture Notes - Lecture 8: Instruction Register, Program Counter, Picosecond

• School: Hofstra University
• Department: Computer Science (CSC)
• Course: CSC 005
• Professor: Dennis Mirante

Document Summary

Csc 005 intro to computer science (3/28/17) Sizes in perspective: admiral grace murray hopper"s illustration. A coil of wire nearly 1,000 feet long: distance traveled by an electron along the wire in a microsecond. Short piece of wire: space of a nanosecond. Bag contains grains of pepper: space of picosecond. Arithmetic/logic unit: performs basic arithmetic operations (addition and subtraction). Logic operations: and and not: modern alus have special storage units called registers accessed faster than main memory. Input: data/programs from the outside world that enter the computer system: output: results stored in computer are made available outside the system. Instruction register (ir): contains instruction being executed: organizing force in the computer, program counter (pc): contains address of next instruction to be executed, cpu: alu + control unit. Flow of information: bus: transfers data between components in a computer. Connects cpu, main memory, i/o devices, and other components.