Computer Science OverviewComputer Science OverviewChapter Three-Operation System Chapter Three-Operation System (1)(1)

JainShing Wu

Operating SystemOperating SystemA collection of software

◦Manages computer hardware resources

◦Provides common services for computer programs

◦A vital component of the system software in a computer system

Operating SystemOperating System

HistoryHistoryEarly computers were built for a

series of single tasks◦Calculator

In the 1940s, the earliest electronic digital systems had no operating systems

Electronic system were programmed on rows of mechanical switches or by jumper wires on plug boards

HistoryHistoryAfter programmable general

purpose computers were invented, machine languages were introduced◦Speed up the programming process

HistoryHistoryBasic operating system features

were developed in the 1950s◦Automatically run different programs◦Hardware features were added

Use of runtime libraries Interrupts Parallel processing

HistoryHistoryEach user

◦Had sole use of the computer for limited time

◦Arrive at a scheduled time with program and data on punched paper cards and/or punched tape

The program would be loaded into the machineThe execution of program called job

The machine would be set to work until the program completed or crashed

HistoryHistoryOperating systems did not exist

in the modern and more complex computers until the early 1960s

Batch processing

QueueQueueFirst in, first out (FIFO)Jobs are removed from the queue

in the order in which they arrivedEx:

Waiting zone

Processing zone

Finishing zone

HistoryHistoryBatch processing

◦Each job is accompanied by a set of instructions

◦These instructions are encoded using job control language (JCL) and stored in job queue

◦Drawback No interaction between user and

submitted job

HistoryHistoryInteractive processing

HistoryHistoryInteractive processing

◦Terminal (a CRT and a keyboard) Input the command Read the computer’s response

◦Serve a user at a time

HistoryHistoryReal-time processing

◦Early Execute tasks under a deadline

◦Now Response occur in real-time Computer performs the task in

accordance with deadlines in its environment

HistoryHistoryReal-time processing

◦1960s, computers are still expensive◦One user at a time (x)◦More users at the same time (O)◦Several users uses terminals to

connect to computer at the same time

HistoryHistoryTime-sharing system

◦Multi-programming◦Time divided into several intervals◦Execute jobs one interval at a time

HistoryHistoryIn the 1980s

◦Personal computers became popular ◦Operating system were made for

these PCs ◦Similar in concept to these operating

systems used on larger computers

Type of Operating SystemType of Operating SystemMicro-computer

◦PC-DOS, MS-DOS, MS Windows 95, Win98, Win 2000, Win XP, Win 7, Apple Macintosh, Unix like systems, etc

Mainframe◦Unix, Solaris, Win NT, Unix like

systems, etc

Disk Operating System Disk Operating System (DOS)(DOS)IBM PC DOS

◦IBM force assembled to develop the PC

◦Decided that critical components of the machine, including the operating system

PC-DOSPC-DOS

Disk Operating System Disk Operating System (DOS)(DOS)Microsoft DOS (MS-DOS)

◦Written by Tim Paterson ◦Owned by Seattle Computer

Products◦Original name is 86-DOS ◦Known as the Quick-and-Dirty

Operating System or Q-DOS

MS-DOSMS-DOS

MicroSoft Windows 95MicroSoft Windows 95A consumer-oriented graphical

user interface-based operating system

Separate MS-DOS and Windows products

Graphical user interface (GUI) and "plug-n-play" features

Extend 16 bits to 32 bits

MicroSoft Windows 95MicroSoft Windows 95

Windows 98Windows 98Windows 98

◦Is Windows 95 successor◦Enhances the internet ability◦Includes Internet Explorer 4.01. and

many other Internet companion applications

Windows 98Windows 98

Windows 7Windows 7Extends from 32 bits to 64 bits

Apple MacintoshApple MacintoshDevelop by Apple Inc.One click for software installAll hardware are not easy

updated

Unix and Unix Like Unix and Unix Like SystemsSystemsOS of MainframeA multitasking, multi-user

computer operating systemDeveloped in 1969 by a group of

AT&T employees at Bell Labs

Unix and Unix Like Unix and Unix Like SystemsSystems

Unix and Unix-Like Unix and Unix-Like SystemsSystemsDirect interactionMoving away from the total

control of businesses like IBM and DEC

AT&T giving the software away for free

Running on cheap hardwareBeing easy to adopt and move to

different machines

GNU AnnounceGNU AnnounceIn 1983Richard Stallman announced the

GNU projectAn ambitious effort to create a

free software Unix-like system; "free" in that everyone who received a copy would be free to use, study, modify, and redistribute it

GNU General Public License GNU General Public License (GPL)(GPL)Derived works can only be

distributed under the same license terms

GPL ◦Grants the recipients of a computer

program the rights of the free software definition

◦Uses copyleft to ensure the freedoms are preserved, even when the work is changed or added to

FreeBSDFreeBSDFreeBSD is a free Unix-like

operating system descended from AT&T UNIX via BSD UNIX

FreeBSDFreeBSD

Linux-UbuntuLinux-UbuntuA computer operating system

based on the Debian Linux distribution

Distributed as free and open source software

Desktop environmentGraphical interface

Linux-UbuntuLinux-Ubuntu

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