OPERATING SYSTEMS HISTORY

Maria Aslam 2015-CPE-33

 Definition: An operating system is an interface between the hardware of a computer and the user (programs or humans) that facilitates the execution of other programs and the access to hardware and software resources. An operating system is a software consisting of programs and data that runs on computers and manages the computer hardware and provide common services for efficient execution of various application softwares. OPERATING SYSTEMS:

is simply a connection between user/application and hardware as shown in figure.

Manage hardware devices Organized File Storage Run Programs Provide user interface  Operating System: Functions

 History: 1940’s First Computer(no operating systems),plug boards 1950’s Batch processing 1960’s Multiprogramming(Timesharing) 1970’s Multimode,Ics,TCP/IP 1980’s Minicomputers &Microprocessors,GUI 1990’s PC’s,GUI,OOP 2000-> Middleware,webservers

 Generations: First Generation : Vacuum tubes,Batch processing Second Generation : Transistors,Batch systems Third generation : Ics and Multiprogramming Fourth Generation : PCs,Workstations,Microprocessor Fifth Generation : WWW,windows,GUI,MS office Last Generation beyond 2000: Middleware,Massive parallel processing

First Generation : In earlier 1940’s Machines were so primitive,programmers entered machine language programs one bit at a time on rows of mechanical switches(plug boards). Plug BoardsCipher

Eventually programmers entered their machine language programs on punched cards.  Punched Card: Punch cards also known as Hollerith cards and IBM cards are paper cards containing several punched or perforated holes that were punched by hand or machine to represent data.

Punched card

General motors Research Laboratories implemented the first operating system in early 1950’s. System of 1950’s generally executed only one job at a time. After that the early computers were batch processing computers.  Batch Processing: Batch processing is the execution of a series of jobs in a program on computer.The job typically executed without user input for minutes. Example: Credit card billing,Payroll, inventory.

Batch Processing System

 In batch systems, repeated jobs are done fast  No need for additional hardware and system support to input data

 Advantages Batch processing takes much of the work of the operator to the computer, Repeated jobs are done in batch system without manual intervention. Not need special hardware to support input data. It can work offline that make less stress on processor.  Disadvantages Difficult to debug batch system. Batch system was costly. No operating system. Due to lack of protection scheme, one batch job can affect pending jobs.

 Second Generation : Systems of 1960’s was also batch processing systems. But these included many peripheral devices such as: Card Readers Card Punches Printers Tape Drives Disk Drives

 Example:

1960’s systems improved resources utilization by allowing two jobs at a time: Using processors processor bound jobs Peripheral devices (I/O) I/O bound jobs. Turn arround Time: The time required foe the execution of command from the submission of command request this time called turn arround time. OS designers developed multiprogramming systems to manage several jobs at once.  Multiprogramming Systems: In multiprogramming environment operating system rapidly switches the processor from job to job

 Degree of Multiprogramming: It indicates how many jobs can be managed at once. Multiprogramming assumes a single shared processor. Multiprogramming increases CPU utilization by organizing jobs so that the CPU always has one to execute. A time-shared operating system uses the concept of CPU scheduling and multiprogramming to provide each user with a small portion of a time-shared CPU.

Each user has at least one separate program in memory.

 Interactivity Interactivity refers to the ability of users to interact with a computer system. In 1960s user interacted with the computer via “Dumb Terminals” which were online. An Operating system does the following activities related to interactivity: Provides the user an interface to interact with the system. Manages input devices to take inputs from the user. For example, keyboard. Manages output devices to show outputs to the user. For example, Monitor.

 Time sharing: Timesharing is a technique which enables many people, located at various terminals, to use a particular computer system at the same time.  Real Time: A real time operating system (RTOS) is an operating system (OS) intended to serve real time applications that process data as it comes in, typically without buffer delays.

 Some Computers of this Generation were: IBM 1620 IBM 7094 CDC 1604 CDC 3600 UNIVAC 1108

 Advantages: High and efficient CPU utilization. User feels that many programs are allotted CPU almost simultaneously.  Disadvantages: CPU scheduling is required. To accommodate many jobs in memory, memory management is required.

 Third Generation : Third generation operating systems were multimode systems. Some of them simultaneously supported batch processing, time sharing, real-time processing, and multiprocessing. Integrated circuits(chips) are used in computers. Department of Defense's TCP/IP communications standards became widely used especially in military and university computing environments in United States. Security problems increased with these communications.

Integrated circuit

 Disadvantages: They were large and expensive. The latest technology is required for manufacturing of microprocessor. Security Problems

Fourth Generation : The 1980’s was a decade of personal computer and workstation(Network operating systems and distributed operating systems) PC

A workstation is a special computer designed for technical or scientific applications. Intended primarily to be used by one person at a time, they are commonly connected to a local area network and run multi-user operating systems.

IBM personal computer released in Apple Macintosh personal computer released in Ms-DOS was chosen as the operating system for IBM PC. Microprocessor technology evolved to the point that it become possible to built desktop computers as powerful as the mainframes of 1970’s. LSI used in computers. Large scale integration (LSI) is the process of creating an integrated circuit (IC) by combining thousands of transistors into a single chip. The microprocessor is a LSI device.

Microprocessor

Graphical user interface built on top of the DOS operating system in the mids of 1980s.  Graphical user interface: A Graphical User Interface (GUI for short) allows users to interact with the computer hardware in a user friendly way.

 Disadvantages: Very advanced technology was required to fabricate to the ICs. Very advance technology was required to make the ICs. Air conditioning was required in many cases due to ICs.

 Fifth Generation : Hardware performance continued to improve exponentially in the 1990’s. In 1990’s the creation of world wide web led to an explosion in the popularity of distributed computing. Operating systems performed isolated resource management inside a single computer. Microsoft Corporation became dominant in the 1990’s.

Microsoft released Windows 3.0 in In the mid 1980s,Microsoft developed the Windows operating system. The Windows operating system became popular after the 1993 release of Windows 3.1, whose successors, Windows 95 and Windows 98, virtually cornered the desktop operating system market by the late 90s.

Windows 0.3

Windows 3.1

 Open Source Movement: Open source software distributed with the source code. Allows individual to examine and modify software. Linux Operating system and Apache web server were both Open source. Richard Stallman launched the GNU project. Disagreed with the concept of paying for permission to use software. Open source initiative (0si). Facilitates enhancement of software products.

 Object Oriented Technology: Applications written in object oriented programming language. Reuse Ability of Attributes. Reduced software Development time. Object Oriented Operating systems (OOOS). Concepts such as Inheritance And Interfaces were introduced. Modular operating systems were created. Easier to maintain and extend.

 Generation beyond 2000: Middleware has become vital as applications are published on the World Wide Web.  Middleware: Middleware is computer software that provides services to software applications beyond those available from the operating system. It can be described as "software glue".

World Wide Web and consumers use them via affordable,high-speed Internet connections over cable television lines and digital subscriberlines (DSL). Middleware is Common in Web applications,in which a Web server(the application that sends data to the user's Web browser) must generate content to satisfy a user's request with the help of a database. Middleware Act as a courier between web browser and database.

Web services will help drive the shift toward true distributed computing. For example, the online retailer Amazon.com allows developers to build on line stores that search Amazon's product databases and display detailed product information via Amazon.com WebServices.  Web services: Encompass set of related standards. Enables any applications to Communicate and Exchange data. Web services will help toward true distributed computing. Consumers and professional lines merged in Windows XP. Portable operating systems (POSIX). Mobile Operating systems. Distributed Computing With PDA’S.

 Massive Parallel Processing: MPP (massively parallel processing) is the coordinated processing of a program by multiple processors that work on different parts of the program, with each processor using its own operating syste m and memory. Typically, MPP processors communicate using some messaging interface.

THE END

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