Instructor: Li Ma Department of Computer Science Texas Southern University, Houston August, 2011

Computer Systems Computer is a programmable electronic device Computer has 4 basic computing functions Input Processing Output Storage Types of Computers Supercomputer: large and powerful Mainframe computer: multitasking Minicomputer: for medium-sized business Microcomputer: desktop computer, notebook computer, tablet computer, Personal Digital Assistant (PDA) by Li Ma2

Hardware of Computer Systems Motherboard: the primary printed circuit board in a PC All the other circuit boards in the computer are connected to motherboard CPU RAM chips Expansion cards Processor and coprocessor sockets Memory sockets Serial and parallel ports Peripheral controllers System bus by Li Ma3

Hardware of Computer Systems (cont’) The central processing unit (CPU) Fetch instructions, follow the instructions, and produce some results Control unit Arithmetic and logic unit (ALU) Main memory ( Random-access memory, RAM) It holds the sequences of instructions in the programs that are running and the data those programs are using It is a volatile type of memory, used only for temporary storage Data will be lost when power is off by Li Ma4

Hardware of Computer Systems (cont’) Secondary storage devices Type of memory that can hold data for long periods of time Disk drives: hard disk, floppy disk, Zip disk, etc. Optical devices: compact disk (CD) Flash drives: or thumb drives, directly plug to USB port Input devices keyboard, mouse, scanner, microphone, and digital camera Output devices printer, monitor, and speaker secondary storage devices by Li Ma5

Hardware of Computer Systems (cont’) Others Modem: a communication device Video Card: an expansion card, responsible for transforming graphics and text signals onto the monitor Power Supply: responsible for converting the standard power into an energy form that your computer can use System Buses: channels over which information flows between two or more devices by Li Ma6

Software of Computer Systems Software refers to the programs that run on a computer, there are two categories: Operating System (OS): interface between hardware and software DOS: Disk Operating System Windows Unix Linux: portable Unix Macintosh Application software: developed by users, for some specific purpose by Li Ma7

MS-DOS A set of programs that allows users to interact with a computer Once you turn on the computer, it will be loaded It has a command-line interface File and Directory Structure Tree-like Nodes: directories and files Windows 95 folded DOS into GUI (Graphical User Interface) Friendly interface Easier to operate by Li Ma8

Windows Windows 95 First truly combined the operating system and GUI for the Intel-based computers Windows 98 Logical extension of Windows 95 More efficient Integrates World Wide Web (WWW) capabilities into the operating system Newer version of Windows Windows 2000, Windows XP, Windows Vista, … by Li Ma9

Windows (cont’) Icons and Graphical User Interfaces (GUI) A software program that allows you to communicate with your computer by using a pointing device like mouse. Application Suites in Windows Microsoft visual studio Microsoft office Internet Explorer, Etc. by Li Ma10

Windows XP Windows refers to the operating system that runs the PC or PC-compatible computers It is loaded once you turn on the computer Desktop: the basic screen on which Windows and application run Taskbar, Shortcut icons, Start button, Quick-Launch toolbar, System tray, Mouse pointer A window is a rectangle area for some certain application It can be opened and closed It can also be resized, moved, and reduced to a button (to the task bar) by Li Ma11

Windows XP (cont’) File and Directory Structure Like file cabinets: files and folders My Computer: view your disks, folders and files Create a new folder Copy, move, rename, and delete files Find files and folders Compress (or zip) files by Li Ma12

Microsoft Office A set of powerful applications (or a suite) that has been designed to work together Share data to combine text, chart & database information in one document Word: word processing Excel: electronic spreadsheet manipulation PowerPoint: making presentation materials Access: manipulating databases FrontPage: developing web pages Outlook: tracking the schedule, checking by Li Ma13

Microsoft Office (cont’) Web aware All applications can be used to access or generate HTML document Starting an office application Double-click the icon on the desktop (shortcut) Invoke the Start, Programs command sequence Open an associated file Office Assistant Very useful to new user by Li Ma14