Processor/Memory Chapter 3 Computer Hardware Processor/Memory Chapter 3

The System Unit The box that holds the processor, memory, motherboard, interface cards, and possibly disk drives and other goodies

Data Representation Data is represented Digitally internally represented as switches with two possibilities: off and on logically represented as two numbers : 0 and 1 called a Binary Digit, or bit.

Data groupings Bit Byte -- collection of 8 contiguous bits patterns ranging from 00000000 to 11111111 256 different patterns ASCII EBCDIC UNICODE -- two bytes Parity used to detect (transmission ) errors

Motherboard Contains the system bus data bus address bus expansion slots memory slots processing unit

Central Processing Unit The place where the computing is actually done Composed of two parts: the control unit and the Arithmetic and Logic unit Control Unit ALU

Control Unit Contains several registers Machine Cycle program pointer instruction register Machine Cycle Fetch Decode Execute Store

Arithmetic and Logic Unit Do the actual processing contain registers for manipulating data

Speed of the Processor System clock pulses millions of times per second. Each pulse is called a clock cycle Each part of the Machine Cycle has a fixed clock length. Words and Word Size -- how much data will fit in a register Bus width -- how much data can be moved down the data bus

Primary Storage Integrated Circuits or RAM chips volatile von Neumann architecture memory addresses vs contents memory “size” and address bus

Types of memory RAM simms, dimms roms, proms, eproms, eeproms flash cache, L1 Cache, L2 Cache cmos

Other stuff on the Motherboard Expansion slots parallel ports serial ports floppy disk connectors IDE connectors

Number Systems and their relationship to computers decimal binary hexadecimal