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Introduction to Operating Systems (OS). What is Operating System. Commonly abbreviated to OS or O/S ) is an interface between hardware and user. OS is most important programme that runs on a computer. - PowerPoint PPT Presentation
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What is Operating System
Commonly abbreviated to OS or O/S) is an interface between hardware and user.
OS is most important programme that runs on a computer.
Every general-purpose computer must have an operating system to run other programs.
An operating system is a software program that enables the computer hardware to communicate and operate
with the computer software. Without a operating system, a computer would be useless.
Function of OS OS does with two things:
ONE
It manages the hardware resources
TWOand software resources of the system.
In a desktop computer, these resources include such things as the processor , memory, disk space and many more….
In cell phones, they include the keypad, the screen, the address book, the phone dialer, the battery and the network connection.
OS provides a stable, consistent way for applications to deal with the hardware without having to know all the details of the hardware.
Computer OS When you turn on the power to a computer, the first program that runs is usually a set of instructions in the computer's Read – only memory
(ROM). This code examines the system hardware to make sure everything is functioning properly.
This power-on self test BIOS checks the CPU and memory for errors and stores the result in a special memory location.
Once the boot process successfully completed, the software loaded in ROM will begin to activate the computer's disk drives.
The operating system's tasks, fall into six categories:
– Processor management – Memory management – Device management – Storage management – Application interface – User interface
Classification of OSOperating systems can be classified as follows:
Multi UserAllows two or more users to run programs at the same time. Some
operating systems permit hundreds or even thousands of concurrent users.
Multiprocessing: It runs a program on more than one CPU.
Multitasking Allows more than one program to run concurrently.
Multithreading Allows different parts of a single program to run at the same time.
Real Time Responds to input instantly, these are General-purpose operating systems, DOS and UNIX, are not real-time
Operating systems can be designed according to functionality,Supercomputing, mainframes, servers, workstations, desktops, handheld devices, real time systems, or embedded systems use different OS.
Supercomputing is primarily scientific computing, usually deals with real systems. There mechanism is collections of computers that work together high processing, space and high tech research applications, large animations and special effects.
Mainframes are large centralized computers and deals bulk of business and large scale database computing through time sharing. Mainframes (powerful and clusters of computers) are still useful for as centralized billing systems, inventory systems, database operations, etc.
Minicomputers which were smaller, less expensive versions of mainframes for businesses that couldn’t afford true mainframes.
Servers are computers or groups of computers used for internet & intranet serving, print, file and application serving. Servers are also sometimes used as mainframe replacements.
Desktop operating systems are used for personal computers.
Workstations are more powerful versions of personal computers. A particular workstation (like desktops) and run a more powerful desktop operating system, but workstations run on more powerful hardware and often have software associated with larger computer systems.
Handheld operating systems are much smaller and less capable than desktop operating systems, so that they can fit into the limited memory of handheld devices.
Real time operating systems (RTOS) are specifically designed to respond to events that happen in real time. This can include computer systems that run factory floors, computer systems for emergency room or intensive care unit equipment (or even the entire ICU), computer systems for air traffic control, or embedded systems. RTOSs are grouped according to the response time that is acceptable (seconds, milliseconds, microseconds) and according to whether or not they involve systems where failure can result in loss of life.
Embedded systems are combinations of processors and special software that are inside of another device, such as the electronic ignition system on cars
History of OS1950s
Some operating systems from the 1950s include: FORTRAN Monitor System, General Motors Operating System, Input Output System, SAGE (monitor weapons systems), and SOS.
Batch Processing systems Batch systems automated the early approach of having human
operators load one program at a time. The operating system would schedule “batches” of related jobs. Output would be punched cards,magnetic tapes, printed material, etc.
Examples of operating systems that were primarily batch-orientedinclude: BKY, BOS/360, BPS / 360, CAL, and Chios.
History of OS1960sSome operating systems from the early 1960s include:Admiral, B1, B2, B3,B4, Basic Executive System, BOS/360, Master Control Programme and SABRE.
1970sSome operating systems include: BKY, Chios, DOS/VS, Master Control Programme, OS/VS1, and Unix.
1980sSome operating systems include: AmigaOS, DOS/VSE, HP-UX,Macintosh, MS-DOS, and ULTRIX.
1990sSome operating systems include: BeOS, BSDi, FreeBSD, NeXT, OS/2, Windows 95, Windows 98, and Windows NT.
2000sSome operating systems include: Mac OS X, Syllable, Windows 2000,
Windows Server 2003, Windows ME, and Windows XP.
OS Families
BSD (Berkeley Software Distribution - Unix)
Darwin (Mac OS X)
Linux
SunOS (Solaris/OpenSolaris)
Windows (98, NT, ME, XP, Vista & 7)
Examples of OS Microsoft Windows Operating Systems
Microsoft Windows is a family of operating systems its older systems were MS-DOS for the IBM PC.
June 2008, Microsoft Windows holds a large amount of the worldwide desktop market share and web and database servers.
October 2001, the most widely used version of the Microsoft Windows family is Windows XP.
November 2006, Microsoft released Windows Vista, a new operating system with added new features and architectural changes. Its new user interface and visual style called Windows Aero, a number of new security features such as User Account Control, and a few new multimedia applications such as Windows DVD Maker are important features.
Windows 7 is currently under development; Microsoft has stated that it intends to scope its development to a three-year timeline, placing its release sometime around January 2010.
Examples of OS
Unix and Unix-like operating systems
The Unix-like family is a diverse group of operating systems, withseveral major sub-categories including System V, BSD, and Linux. The name “UNIX“ is a trademark of The Open Group.
Unix-like systems run on a wide variety of machine architectures. They are used heavily for servers in business, as well as
workstations in academic and engineering environments. Free software Unix variants, such as GNU, Linux and BSD, are popular areas.
Some Unix variants like HP's HP-UX and IBM's AIX are designed torun only on that vendor's hardware.
Apple's Mac OS X, a Hybrid Kernel based BSD variant derived from NeXTSTEP, Mach, and FreeBSD, has replaced Apple's earlier
(non-Unix) Mac OS.
Examples of OS Mac OS
Max OS X is a line of graphical operating systems developed, marketed, and sold by Apple Macintosh Inc. Mac OS X is the world's second most widely used OS after Windows. Mac OS X is the successor to the original MAC OS, which had been Apple's primary operating system since 1984.
Mac OS first released in 1999 as Mac OS X Server 1.0 with a desktop-oriented version Mac OS X v10.0 following in March 2001.
Since then, five more distinct "end-user" and "server" editions of Mac
Mac OS X v10.5 is released and usually referred to by Apple and users as "Leopard".
Mac OS X Server includes work group management and administration software tools that provide simplified access to key network services including a mail transfer agent.
Examples of OS
Plan 9
Bell Labs developed Plan 9 and Inferno, which were engineered for modern distributed environments.
Plan 9 was designed from the start to be a networked operating system.
Plan 9 has yet to become as popular as Unix, but it has an expanding community of developers.
Examples of OS
Real-time operating systems
Real Time Operating System (RTOS) is a multitasking operatingsystem intended for applications with fixed deadlines (Real Time Computing).
Such applications include some small embedded systems, automobile engine controllers, industrial robots, spacecraft,industrial control, and some large-scale computing systems.
An popular example of such a large-scale real-time operating system was Transaction Processing Facility developed by
American Airlines & IBM for the Sabre Airlines Reservation System.
Examples of OS
Embedded systems
Embedded OS are use dedicated operating systems.
In some cases, the "operating system" software is directly linked to the application to produce a Special-purpose program.
Embedded systems that have fixed deadlines use a real time operating system such as VxWorks, eCos, QNX, MontaVista Linux and RTLinux.
Some embedded systems use operating systems such as Symbian OS, Palm OS, Windows CE, BSD and Linux although such operating systems do not support real-time computing.
Examples of OS
BeOS
This OS is designed for real-time video and multimedia applications. It's also used by Palm Computing.
It newer version called OpenBe contain advanced operatingsystem capabilities.
Examples of OS
QNX
It is complete real-time operating system available with an Internetexploration browser included. This operating system is widely used in British Telecom.
Atheos
A relatively new GUI multi-tasking operating system available onthe PC. AtheOS is a free desktop operating system runs on
Intel, AMD and other compatible processors and supports Multi Processor architecture.
OS TYPES• Linux / Variants• MacOS• MS-DOS• IBM OS/2 Warp• Unix / Variants• Windows CE • Windows 3.x • Windows 95 • Windows 98• Windows 98 SE• Windows ME• Windows NT• Windows 2000• Windows XP• Windows Vista
