System Software

CSCI-N 100Department of Computer and Information

Science

Operating SystemA set of programs that perform certain functions Starting the computer Managing programs Distributing memory Coordinating the processor and

peripherals Enabling user interaction with the

computer

Starting the computerCold boot – power is turned off O/S in ROM (read-only memory) loads BIOS

(basic input/output system) into computer memory

BIOS conducts Power on self-test (POST) to check for operability

BIOS searches for O/S CMOS (complimentary metal-oxide semiconductor)

determines where to look O/S components (kernel) loaded into memory

from storage O/S takes control of computer

Managing programsSingle-tasking Run one application at a time

Multi-tasking The ability to run more than one program at a

time Foreground – program in use Background – idle program

Multi-threading Multiple parts (thread) running simultaneously

Multiprocessing Dual core processors or multiple processors

Managing MemoryAllocates memory area for each running program Keeps programs from leaking into one another

Failure results in corrupt data, programs ‘crash’, error messages

CTRL + ALT + DEL used to close corrupt program Virtual memory an extension of RAM

Data/instructions swapped between RAM and hard drive

Works with direct memory access (DMA) to control peripherals access to RAM

User InterfacePart of the O/S that lets user and computer ‘talk’ to each otherTypes of operating systems Command line

Requires user to type keywords/commands to enter data/give instructions

Graphical User Interface (GUI) Uses little graphics – icons User uses a pointing device to enter data/commands

Mouse Joystick Keyboard Other types

Operating Systems

MS-DOSUNIXLINUXMAC OSWINDOWS

MS-DOS (command line)

UNIX (command line)

Developed by AT&T in 1970s

First preemptive multitasking system

Developed concepts of file management and path names

Client/server networking system

Widely used by corporations

LINUX - Developed in 1991 by UNIX, Competes with Windows and MAC, Powerful and free

MAC OS – First GUI (1984)

http://www.apple-history.com/movies/1984.mov

WINDOWS – 3.X

Includes Windows 3.0, 3.1, 3.11, and Windows for Workgroups 3.1

Not a true operating system

Uses cooperative multitasking

WINDOWS

Windows 95 True operating

system Uses preemptive

multitasking Downward

compatible with DOS

Considered a transitional system

System UtilitiesSystem utilities are programs that help the operating system manage the computer system’s resources.

Types of utilities: File management

File finders

Backup utilities

Antivirus software

File compression

Disk scanning

File defragmentation

File Finder - File finders are programs that enable the user to find files on a storage device

File management

•Known as a file manager.

•Enables the user to perform various tasks with files, folders, and directories on storage devices.

•Tasks include:

Creating folders

Saving, deleting, copying, and moving files and folders

Examining the contents of files

Launching application programs

File Compression - A file compression utility reduces the size of a file.

Disk Scanning - A disk scanning utility is a program that detects and fixes physical and logical problems on storage devices

File Defragmentation - A file defragmentation utility is a program that moves data on a storage device to improve performance.

Apple's 1984: The Introduction of the Macintosh in the Cultural History of Personal Computers by Ted Friedman

Revised version of a paper presented at the Society for the History of Technology Convention, Pasadena, California, October 1997.

http://www.apple-history.com/movies/1984.mov

http://www.duke.edu/~tlove/mac.htm

Slide 13

Resources

http://en.wikipedia.org/wiki/File_managers

http://www.explorerxp.com/

http://www.newplanetsoftware.com/systemg/screenshots.php