01-02-2013, 02:31 PM
An operating system (OS)
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Introduction
An operating system (OS) is a set of software that manages computer hardware resources and provides common services for computer programs. The operating system is a vital component of the system software in a computer system. Application programs require an operating system to function.
Time-sharing operating systems schedule tasks for efficient use of the system and may also include accounting for cost allocation of processor time, mass storage, printing, and other resources.
For hardware functions such as input and output and memory allocation, the operating system acts as an intermediary between programs and the computer hardware, although the application code is usually executed directly by the hardware and will frequently make a system call to an OS function or be interrupted by it. Operating systems can be found on almost any device that contains a computer—from cellular phones and video game consoles to supercomputers and web servers.
History of operating systems
Early computers were built to perform a series of single tasks, like a calculator. Operating systems did not exist in their modern and more complex forms until the early 1960s. Basic operating system features were developed in the 1950s, such as resident monitor functions that could automatically run different programs in succession to speed up processing. Hardware features were added that enabled use of runtime libraries, interrupts, and parallel processing. When personal computers became popular in the 1980s, operating system were made for them similar in concept to those used on larger computers.
In the 1940s, the earliest electronic digital systems had no operating systems. Electronic systems of this time were programmed on rows of mechanical switches or by jumper wires on plug boards. These were special-purpose systems that, for example, generated ballistics tables for the military or controlled the printing of payroll checks from data on punched paper cards. After programmable general purpose computers were invented, machine languages (consisting of strings of the binary digits 0 and 1 on punched paper tape) were introduced that sped up the programming process (Stern, 1981).
The functions of an operating system
Memory management :-
Among other things, a multiprogramming operating system kernel must be responsible for managing all system memory which is currently in use by programs. This ensures that a program does not interfere with memory already in use by another program. Since programs time share, each program must have independent access to memory.
Following are the some well know memory management schemes that are commonly employed in many type of computer configuration.
• Single contiguous allocation.
• Relocatable partitioned allocation.
• Page allocation.
• Demand paged allocation.
• Segmented allocation.
Processor Management:-
A processor is a hardware device that is capable to executing a sequence of instructions. The major task of and efficiently by the processor (CPU).
device management:-
This topic provides system administrators with conceptual information that
can affect your selection of options when performing such tasks as backing
up and restoring the system, managing physical and logical storage, sizing
appropriate paging space, and so on. It provides complete information
about how to perform such tasks as managing logical volumes, storage,
and resources. System users can learn how to perform such tasks as
running commands, handling processes, handling files and directories, and
basic printing. Other topics useful to users and system administrators
include creating and re-sizing paging space, managing virtual memory,
backing up and restoring the system, managing hardware and pseudo
devices, using the System Resource Controller (SRC), securing files, using
storage media, customizing environment files, and writing shell scripts.
This topic is also available on the documentation CD that is shipped with
the operating system.
TYPES OF OPERATING SYSTEM
An operating system is the single most important software when you run a computer, it is what takes care of pretty much everything on a computer system, while the majority of computers we see happen to be using one ‘type’ of operating system performing the same functions, operating systems can be branched into several different types as well. It’s been a while since I’ve shared a fairly technical post on Computer Realm so I guess today would be a good day for one.
WINDOWS XP :-
Windows XP is an operating system produced by Microsoft for use on personal computers, including home and business desktops, laptops and media centers. First released to computer manufacturers on August 24, 2001, it is the second most popular version of Windows, based on installed user base.] The name "XP" is short for "eXPerience" highlighting the enhanced user experience.
Windows XP, the successor to Windows 2000 and Windows Me, was the first consumer-oriented operating system produced by Microsoft to be built on the Windows NT kernel. Windows XP was released worldwide for retail sale on October 25, 2001, and over 400 million copies were in use in January 2006. It was succeeded by Windows Vista in January 2007. Direct OEM and retail sales of Windows XP ceased on June 30, 2008. Microsoft continued to sell Windows XP through their System Builders (smaller OEMs who sell assembled computers) program until January 31, 2009. On April 10, 2012, Microsoft reaffirmed that extended support for Windows XP and Office 2003 would end on April 8, 2014 and suggested that administrators begin preparing to migrate to a newer OS.