v Power Supply Fan v Motherboard CPU

v Power Supply, Fan v Motherboard • CPU, Co-processor • Heat Sinks • Memory Chips (RAM, ROM, CMOS) • Expansion Slots/Expansion Cards – Sound Card, Network Card, Video Capture Card • System Clock • Buses (System and Expansion(ISA, PCI, AGP, USB and 1394 bus) • Ports (back side of system unit) – Serial, Parallel, Video, USB 2. 0, Midi, SCSI, Wireless, 1394 or Fire. Wire – keyboard/Mouse, Hard Drive, Monitor, Printer, other external devices • Hard Drives, Floppy Drives, Cables • Glue Chips

CPU v v CPU Chip = a small piece of semi conducting material that integrated circuits are etched. An integrated circuit is a pathway capable of carrying electrical current and contains millions of transistors or gates that open or close the circuit for the signal One of the most important ones is the CPU 4044 Chip 8088 Chip 5 Mg. Hz

Central Processing Unit What is the central processing unit (CPU) ? ° ° Interprets and carries out basic instructions that operate a computer Also called the processor CPU

Common Processors Intel, AMD, IBM and Motorolla n n n Server Processors n Xeon MP, Itanium 2, Pentium, Opteron, Athlon Desktop Processors n Pentium D with Dual Core Processor, Pentium 4 (with HT technology), Celeron, Duron, Power. PC Mobile Processors n Pentium Duo, Celeron M, Pentium M, Mobile Athlon, Duron

Central Processing Unit What are the components of the CPU? CPU Control Unit Arithmetic/ Logic Unit (ALU)

Central Processing Unit What is the control unit? ° Directs and coordinates operations in computer Control unit repeats four basic operations: Control Unit ° ° Fetch - obtain program instruction or data item from memory Decode - translate instruction into commands Execute - carry out command Store - write result to memory

Central Processing Unit What is a machine cycle? ° Four operations of the CPU comprise a machine cycle ° Also called instruction cycle • Instruction time (i-time) - time taken to fetch and decode • Execution time (e-time) - time taken to execute and store e-time i-time

Central Processing Unit What is the arithmetic/logic unit (ALU) ? v CPU component that performs execution part of the machine cycle Arithmetic Comparison (greater than, equal to, or less than) (addition, subtraction, multiplication, and division) d. an. . or. . not. Logical (AND, OR, NOT)

Central Processing Unit What is pipelining? ° ° CPU begins executing second instruction before completing first instruction Results in faster processing Machine Cycle (without pipelining) Machine Cycle (with pipelining) Instruction 1 Instruction 2 Instruction 3 Instruction 4

Central Processing Unit What is a register? ° Temporary storage area that Stores holds data instruction and while it is instructions being decoded Stores location from where instruction was fetched Stores results of calculation Stores data while ALU processes it

Central Processing Unit What is the system clock? Synchronizes all computer operations ° Each tick is clock cycle ° MHz - one million ticks of system clock GHz – one billion ticks of system clock

Central Processing Unit How do personal computer processors compare?

Data Representation v Two states v Binary numbering system • ASCII (American Standard Code for Information Interchange) • EBCDIC (Extended Binary Coded Decimal Interchange Code)

Data Representation What are two popular coding systems to represent data? ° ° ASCII - American Standard Code for Information Interchange EBCDIC - Extended Binary Coded Decimal Interchange Code

Data Representation How is a character sent from keyboard to computer? Step 1: Press letter T Step 2: Electronic signal for letter T sent to system unit Step 3: Signal changed to its ASCII code (01010100) and stored in memory Step 4: After processing, binary code for letter T is converted to image on output device

Memory What is memory? ° Temporary storage area for operating system, application programs, and data ° Consists of one or more chips on motherboard ° Each byte stored in unique address seat C 22 seat A 22 seat B 22

Memory How is memory measured? ° By number of bytes available

Memory What are two types of system unit memory? volatile memory Loses its contents when volatile memory computer's power Losesis turned off when its contents the computer's power is turned off nonvolatile memory Does NOT lose its contents when computer’s power is turned off

Memory What is random access memory (RAM)? ° Memory chips that can be read from and written to by processor ° Most RAM is volatile ° The more RAM a computer has, the faster it operates memory module

Types of Memory v RAM • Memory chips in the system unit • Stores programs and data • Volatile • Dynamic RAM (DRAM), must be re-energized – Synchronous DRAM (SDRAM) is faster because it is synchronized to the system clock, 7. 5 ns – DDR SDRAM, 3 ns – RDRAM (Intel and Rambus is trying to push), expensive, 1. 25 ns • Static RAM (SRAM) – Faster and more reliable than DRAM – Does not have to be re-energized as frequently as DRAM – Used for special purposes

v Often smaller in size than processor chips v Packaged on circuit boards • SIMM (single in-line memory module) – old technology current computers use----- • DIMM (dual in-line memory module) • RIMM (Rambus inline memory module v Typically chips SDRAM

Memory What is cache? ° ° ° Helps speed computer processes by storing frequently used instructions and data Also called memory cache, cache store, or RAM cache L 1 cache built in processor L 2 and L 3 cache not built in processor (depends on currency) L 2 advanced transfer cache most common

Cache v Memory cache, cache store or RAM cache • Level 1 (L 1), small capacity (8 Kb to 64 Kb), built directly on the processor • Level 2 (L 2), external cache, on SRAM chips, slightly slower than L 1 cache but has a larger capacity, 64 KB to 4 MB, newer machines L 2 cache is built on the processor and called Advanced Transfer cache- these machines can also have L 3 cache (external) • Machines with cache (10 -40% faster) • Most current machines have 256 K to 512 K of cache

Memory What is read-only memory (ROM)? ° Memory chips that contain data, instructions, or information that is recorded permanently Data can only be read; cannot be modified in ROM is nonvolatile — Contents not lost when computer is turned off BIOS (basic input/output system) Stored on ROM Sequence of instructions computer follows to load operating system and other files when you turn on the computer

Memory What is CMOS? Complementary metal-oxide semiconductor memory Stores information about the computer • • type of disk drives keyboard monitor current time and date Uses battery to retain information when computer is turned off

Memory What is memory access time? ° ° ° Speed at which processor can access data from memory directly Measured in nanoseconds (ns), which is one billionth of a second It takes 1/10 of a second to blink your eye; a computer can perform up to 10 million operations in same amount of time

Expansion Slots and Expansion Cards What is an expansion slot? An opening, or socket, where circuit board is inserted into motherboard ° Expansion card inserted in expansion slot ° expansion card expansion slot

Expansion Slots and Expansion Cards How are expansion cards used?

Ports What is a port? ° Connects external devices to system unit keyboard USB serial port mouse USB printer (parallel port) speaker monitor microphone game port network telephone line in svideo out telephone line out FM reception cable TV

Ports What is a serial port? ° Transmits one bit of data at a time ° Used to connect slow-speed devices, such as mouse, keyboard, modem serial transmission of data byte representation for number 5 (00110101) DB-9 female connector DB-9 male connector byte representation for number 5 (00110101)

Ports What is a parallel port? ° Connects devices that can transfer more than one bit at a time, such as a printer byte representation for number 1 byte representation for number 3 byte representation for number 5 DB-25 male connector DB-25 female

Ports What is a universal serial bus port (USB) ? Connector that supports newer peripherals and plug and play ° Other popular ports include 1394, MIDI, SCSI, and Ir. DA ° 1394 port USB port

PORTS USB, USB 2. 0 Can connect multiple devices MIDI Connects an instrument to the system unit SCSI High speed parallel port used to connect disk drives, 7 devices can be attached 1394 (Fire Wire) Can connect multiple devices requiring fast connections Digital video camcorders, color printers, digital cameras and DVD drives

What is a bus? ° ° Channel that allows devices inside computer to communicate with each other System bus connects processor and RAM Bus width determines number of bits transmitted at one time Word size determines number of bits processor can interpret and execute at a given time processor system bus RAM

Buses What is an expansion bus? ° Allows processor to communicate with peripherals fastest next fastest slowest memory processor PCI bus expansion slots ISA bus expansion slots

Expansion Bus v Expansion bus allows the CPU to connect to the peripheral device attached to the expansion card v ISA (Industry Standard Architecture) • Mouse, Modem, Soundcard v PCI (Peripheral Component Interconnect) • Hard Drive (4 X faster than ISA) v AGP (Accelerated Graphics Port) which is • actually a bus • Bus designed for a video card (AGP video card) v USB (Universal Serial Bus), multiple devices, • USB connects to the PCI bus

Market Tiers v Top Tier • IBM, Apple, Compaq and HP v Second Tier • Newer companies with high sales volume – Gateway, Dell, Packard Bell • Third Tier – Smaller Start up Companies – Mail Order

Marketing Channels v Computer Retail Store v Mail Order Suppliers v Value – added Reseller v Manufacturer Direct