计算机系统(主机)

CH 4 Copyright 2003 The McGraw-Hill Companies, Inc. Types of system units Binary codes System unit components Types of memory Expansion slots and boards Buses and ports System Unit Houses electronic components Basic components System board Microprocessor Memory Types of System Units Desktop Notebook *Tablet PC Handheld Computer The system unit, also known as system cabinet, is a container that houses most of the electronic components that make up a computer system. Notebook system units are portable and much smaller. Desktop System Units Contain the system’s electronic components and selected secondary storage devices. Input/Output devices located outside the system cabinet(主机箱) Notebook System Units Portable Monitor attached by hinges Keyboard and pointing devices integral to the system unit Notebook system units are portable and much smaller. Table PC System Units Portable Support the use of a stylus or pen to input commands and data Monitor swivels and folds onto its keyboard or attached to the system unit Handheld Computer System Units Smallest system unit All input/output and secondary storage devices integral to the system unit Handheld Computer System Units are the smallest and are designed to fit into the palm of one hand. Binary System 0s and 1s Each 0 or 1 is a bit 8 bits = 1 byte American Standard Code for Information Interchange (ASCII) Extended Binary Coded Decimal Interchange Code (EBCDIC) Unicode ASCII Widely used in microcomputers 1 byte = 1 character Examples Number 3 is represented by 0011 0011 Developed by IBM Used in mainframe computers 1 byte = 1 character Examples Number 3 is represented by 1111 0011 Developed by Unicode, Inc. with support from Apple, IBM, and Microsoft Used to support international languages such as Japanese and Chinese 2 bytes = 1 character System Board Connects all components Data path between devices Also called the main board or motherboard Sockets Connection points on the system board Slots Connection point