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The System Unit By: Brian Domingos. Chapter 4. The System Unit. System unit components are housed within the system unit or system cabinet. The three types are as follows: Desktop -contains electronic components and selected storage devices. Notebook -portable, monitor attached by hinges.
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The System UnitBy: Brian Domingos Chapter 4
The System Unit System unit components are housed within the system unit or system cabinet. The three types are as follows: • Desktop-contains electronic components and selected storage devices. • Notebook-portable, monitor attached by hinges. • PDA (personal digital assistant)-smallest, most portable, contains entire system.
Electronic Representation • Data and instructions are represented electronically with a two-state binary system of numbers (0 and 1). • Binary coding schemes convert binary data into characters. Three such schemes are: 1. ASCII-the most widely used for microcomputers. 2. EBCDIC-developed by IBM and used primarily by large computers. 3. Unicode-16-bit code to support international languages like Chinese and Japanese.
System Board • The system board, also known as the mother board or the main board, connects all the system components. • A chip, also known as a silicon chip, is a postage stamp-sized circuitboard.
Microprocessor • The microprocessor plugs into the system board, and is considered the brains of the system unit. • Two basic components of the microprocessor are the control unit and the arithmetic-logic unit. • The control unit executes programs by directing the other system components. • The arithmetic-logic unit, performs arithmetic and logical operations.
Microprocessor Chips The two types of microprocessor chips are: • Complex instruction set computer (CISC) chips-=the basis for Intel’s Pentium III and Pentium IV microprocessors. • Reduced instruction set computer (RISC) chips-fewer instructions. They are the basis for IBM and Motorola’s PowerPC.
Memory • There are three types of memory chips: RAM, ROM, and CMOS RAM-often called temporary or volatile because contents are lost if computer is disrupted. ROM-permanent and control essential system operations. CMOS-provide flexibility and expandability to computer systems.
Expansion Slots and Cards Example of expansion cards are: • Network adapter cards-connect to a network. • Modem cards-connect over a telephone line • Television boards-contain TV tuner and video capture capabilities, also known as personal video recorder cards.
Bus Lines Bus lines provide data pathways that connect various system components. Four principal types are: • ISA (Industry Standard Architecture)-older and slower but still widely used. • PCI (Peripheral Component Interconnect)-high speed; used to connect CPU, memory, and expansion boards. • AGP (Accelerated Graphics Port)-used for video data • USB (Universal Serial Bus)-fastest; used to support high-speed devices.
Ports and Cables Ports and cables allow external devices to connect to the system unit. • Ports are connecting sockets on the outside of the system unit. The five most common types are serial, parallel, USB, and HPSB, which is also known as FireWire. • Cables are used to connect external devices to the system unit via ports.