GRAP 3175 Computer Applications for Drafting Unit II Computer Hardware

Central Processing Unit (CPU)

Integrated Circuit (IC) Microchip or Chip One complete electronic (semiconductor) circuit on a piece of silicon.

Central Processing Unit (CPU) Arithmetic and Logic Unit (ALU) Control Unit Main Memory Unit

Microprocessor CPU of a microcomputer 1.5 GHz Pentium Mhz PowerPC G4 Motherboard

Arithmetic and Logic Unit (ALU) Arithmetic functions –addition, subtraction, multiplication & division –Logarithms, trigonometry, etc. Logic function –Numbers or conditions are compared –Greater than, less than, equal to, etc.

Control Unit The “traffic cop” of the system System clock

Main Memory Unit Internal memory of a computer Writing - entering data into main memory Reading - retrieving data

Random Access Memory (RAM) Read-write Volatile DRAM, SDRAM, RDRAM

Read-only Memory (ROM) Read Only Info. to start computer Nonvolatile PROM EPROM Flash memory

RAM & ROM at Work

RAM On motherboard –RAM chips (64KB, 256KB, etc.) –SIMMS, DIMMS, RIMMS (256KB - 512MB) RAM card

CACHE Memory 512 KB 1 MB

Communication Pathways Bus Data Bus Bus Architecture Open Architecture Types of buses –ISA, PCI, SCSI, USB, etc

CPU at Work Executing an Instruction Instruction Cycle –Fetch –Decode Execution Cycle –Execute instruction –Place results in memory

Data Representation Overview Binary System -- 1s and 0s –High-voltage state (on) –Low-voltage state (off) Number Number Letter D

Bits & Bytes Bit Byte -- basic unit of measure for memory –nibble Kilobyte (KB) bytes –2 10 vs 10 3 Megabyte (MB) -- 1,048,576 Gigabyte (GB) -- 1,073,741,824 Terabytes (TB) -- 1,099,511,628,000

Computer Words The number of adjacent bits that can be stored & manipulated as a unit. 8, 16, 32, 64, 128 bit Size of register Data Bus 64 / 32

Encoding Systems Alphanumeric characters –Alpha –Numeric ASCII -- 7 bit –American Standard Code for Information Exchange ANSI -- 8 bit –American National Standards Institute Unicode bit

Processing Speed MHz, MIPS, & FLOPS Nanoseconds - billionths of a second Factors –Clock speed –Memory type –Instruction set –Data bus width –Microprocessor –Other support chips / expansion cards

Clock Speed Megahertz (MHz) -- 1 million cycles per second Apple IIe -- 2 MHz Pentium III MHz -1.0 MHz, Pentium GHz

Microprocessor – contained 2,300 transistors – Apple IIe – IBM PC – , IBM AT – ,000 – million –Pentium million

Other Chips / Expansion Cards Math-coprocessor Video card