Computer Operating System Free Essays

An operating system (OS) is like a facilitator, providing an environment for application programs to run in. It provides an interface between computer hardware and the user of the application programs. Application programs are a stored set of instructions for responding to a specific request. We will write a custom essay sample on Computer Operating System or any similar topic only for you Order Now Hardware are the physical devices that make up the system such as the monitor, keyboard, printer, ect. The OS typically includes anywhere from tens to thousands of built-in subroutines called functions which applications can call to perform basic tasks such as displaying a string of text on the screen or inputting a character from the keyboard. The OS allows the user to interact with and obtain information from the hardware through a series of layers. The command layer is the only part of the OS that interacts with the user and sometimes is referred to as the shell. It is the user†s interface to the OS in that the user can request system services via a Job Control Language (JCL), which is the set of commands and their syntax requirements, or through a GUI (Graphical User Interface), the newest command language. The command interpreter decides which services must be executed to process the request and passes these to the service layer. The service layer accepts the commands and translates them into detailed instructions. There is one service call for each number of system requests provided by this layer. It handles functions in process control, file control, and device control. It makes requests to drivers for access to the kernel layer, which interacts directly with the hardware. Input must travel through these layers to reach the hardware and the results must travel back. First and foremost, an operating system must provide a mechanism for starting processes, which most of us know as programs. There are two main types of operating systems: single-tasking and multitasking. DOS is an example of a single-tasking operating system, which simply means that it can only run one program at a time. Windows95 (or newer editions, prior editions were a GUI interface to DOS) is the most widely used multitasking operating system on PC†s. Multitasking means that many programs can run at the same time. The processor (CPU), which selects and executes instructions, must divide its time to each active application to make it appear that all are running at once. These types of operating systems contain schedulers that divide the processor†s time among active processes. The schedulers are located in the kernel. Each process has one or several threads of execution. Every few milliseconds the scheduler takes control of the CPU from the thread it is currently executing, uses a complex time-allocation algorithm to decide which thread should execute next, and continues executing the thread at the point where it was last interrupted. The next fundamental duty of an operating system is to manage the memory – or storage of data – available to it and its applications. The goal in memory management is to give each application the memory it needs without infringing upon memory used by other applications. When a program is loaded and ran, the OS allocates a block of memory to hold the program†s code and data. If a program requires additional memory, it can call a function in the operating system to request more. DOS does not handle memory very well because it runs in real mode, where only 1MB of RAM (Random Access Memory) is addressable. The RAM is volatile memory that stores the running applications but the information is lost when the computer is turned off. Windows95 does a much better job of managing memory because it runs in protected mode, which allows it to use all memory, including extended memory. And even when that much memory isn†t enough, it can make more available by creating virtual memory from free space (space that has nothing stored in it) on a hard disk (non-removable secondary storage hardware device). Virtual Memory is a memory management technique that only loads active portions of a program into main memory. Windows95 also takes steps to prevent an application from accessing memory that it does not own. In DOS, and application can write to someone else†s memory, including the operating system†s, which can crash the entire system. Windows95 runs applications in private address spaces that are logically isolated from each other and identify the start of the file. One of an operating system†s most important components is its file system – the part responsible for managing files stored on hard disks and other mass-storage devices. An operating system provides high-level functions that applications can call to control file I/O, which covers the opening, closing, creating, deleting, and renaming of files. To read a chunk of data from a file, the application calls an operating system function and passes the operating system the file handle (which uniquely identifies an open file), the address in memory where the data should be copied, and the number of bytes to copy. The OS has to identify each sector on the disk that holds a portion of the requested file and program the drive controller to retrieve the information, sector by sector. It has to do this efficiently so that the information is retrieved quickly. The OS finds the right locations on the disk because it keeps a map that contains the name of each file and a record of where it is stored. DOS and Windows95 use a file allocation table as a map to find the locations. Another role that operating systems play in making a computer work is controlling device I/O. A device is a piece of hardware such as a video adapter, keyboard, or mouse. To talk to a device, a program must speak the device†s language, which usually consists of streams of 1†³s and 0†³s. There are thousands of different devices and â€Å"languages†, so the OS helps out by serving as an interpreter. It talks to the devices through device drivers, which are interface programs specially designed for each individual I/O device. Most operating systems like Windows95 come with dozens of different drivers for each I/O device. DOS also uses drivers, but they are often so primitive that the applications perform device I/O by relying on low-level routines encoded in ROM (Read Only Memory – allows the data to be read but not written) in the computer†s BIOS (Basic Input/Output System) or by talking directly to the hardware. How to cite Computer Operating System, Essay examples Computer Operating System Free Essays string(87) " Microsoft disk operating system\) is an operating system commercialized by Microsoft\." 1. Introduction to Operating System:- Computer is a somewhat complex machine. The world has become accustomed to so many choices. We will write a custom essay sample on Computer Operating System or any similar topic only for you Order Now One of the major choices in the modern era is the â€Å"Operating System (OS)†. Operating systems are the central software component to any computer. The main brands of operating system are; Windows Mac OS, Sun Solaris, UNIX, DOS and Linux. Each brand has its own take on what makes up an operating system. Windows is the most commonly used operating system around the world. The most common advantage about Windows is its simplicity. It is now very easy for an inexperienced person to grasp the concept and use the computer with this operating system on it. Windows newest version is Vista and windows7. Vista has made computing a lot safer. Unfortunately, the simplicity which was there with previous versions has gone out of other version of windows. With its focus turning to security, lots of the simple things have been changed to turn into harder tasks. Windows was the first operating system to make the use of the computer simple. This has allowed a computer revolution as more and more of the world becomes computerized using windows as its operating system. The main bad point about Microsoft Vista is the price tag. For what it is, it is not worth the price tag, but people want simplicity, so they pay that little bit extra, so they get to use what they work with on a day to day basis in work places all around the world. Thus, the operating system (OS) is a computer program (system software) that acts as an intermediate between user and computer hardware. This is the first software that we see when we turn on the computer and the last software when we turn off the computer. It provides higher level abstraction. In conclusion, it is a master supervisory program which provides friendly interface for the user to interact with the computer and its peripherals and different application software as well as an environment for programs or applications to execute. 2. Functions:- ? Scheduling: – One of the functions of operating system is to allow multiple programs to execute in single processor system. There is fast switching of processor time for each job waiting for processor time. ? Interrupt handling: – It determines the causes of the interruption and passes control to another module of the program which was interrupted. Memory management: – It stores programs which are needed the most. The management of working area to execute the program is memory management. Memory management is all about transfer between the main and backing storage. ? Virtual memory management: – It is a technique for making computer appear to have more memory than it actually has. By this proces s we can load small portions of hard disk and process it when needed and swapping them out when another process is to be carried out. ? File Management: – It works on the basis of FAT. It allocates space on the storage media to hold each file which is stored and de-allocates space when needed. It maps logical file address to physical disk address. ? Resource allocation: – In large computer systems which are capable of running several programs at once, operating system is responsible for allocating processing time, memory and resources. All the jobs are performed in order as they are to be performed and as they are submitted, then operating system schedules them in order to make the best possible use of the resources. Some Popular Operating System:- 3. 1. Ms-Windows:- Introduction Microsoft is a multinational computer technology corporation. The Microsoft began on April 4, 1975, when it was founded by Bill Gates and Paul Allen in Albuquerque. Microsoft windows are a series of software operating system and graphical user interface produced by Microsoft Corporation. Windows came to dominate the world’s personal computer market. It was stated that windows had approximately 90% of the client operating system market. The most recent client version of Microsoft is Windows Vista and windows7. [pic] Fig: Logo of Microsoft windows History of Microsoft windows:- The history of Microsoft began on April 4, 1975, when it was founded by Bill Gates and Paul Allen in Albuquerque. Its current best-selling products are the Microsoft Windows operating system and the Microsoft Office suite of productivity software. Starting in 1980, Microsoft formed an important partnership with IBM that allowed them to bundle Microsoft’s operating system with computers that they sold, paying Microsoft a royalty for every sale. In 1985, IBM requested that Microsoft write a new operating system for their computers called OS/2; Microsoft wrote the operating system, but also continued to sell their own alternative, which proved to be in direct competition with OS/2. Microsoft Windows eventually overshadowed OS/2 in terms of sales. When Microsoft launched several versions of Microsoft Windows in the 1990s, they had captured over 90% market share of the world’s personal computers. [pic] Fig: Microsoft staff photo from December 7, 1978. From left to right: Top: Steve Wood, Bob Wallace, and Jim Lane. Middle: Bob O’Rear, Bob Greenberg, Marc McDonald, Gordon Letwin. Bottom: Bill Gates, Andrea Lewis, Marla Wood, Paul Allen. Versions:- |Release date |Product name |Current version / build | |Nov 1987 |Windows2. 03 |2. 3 | |Mar 1989 |Windows2. 11 |2. 11 | |May 1990 |Windows3. 0 |3. 0 | |Mar 1992 |Windows3. 1x |3. 1 | |Oct 1992 |Windows for workgroups3. 1 |3. 1 | |Jul 1993 |Windows NT3. 1 |NT3. 1 | |Dec 1993 |Windows for workgroups3. 1 |3. 11 | |Jan 1994 |Windows 3. 2(released in simplified |3. 2 | | |Chinese only) | | |Sep 1994 |Windows NT 3. 5 |NT 3. 5 | |May 1995 |Windows NT 3. 51 |NT 3. 51 | |Aug1995 |Windows 95 |4. . 950 | |Jul 1996 |Windows NT4. 0 |NT4. 0. 1381 | |Jun 1998 |Windows98 |4. 10. 1998 | |M ay 1999 |Windows 98SE |4. 10. 2222 | |Feb 2000 |Windows 2000 |NT 5. 0. 2195 | |Sep 2000 |Windows Me |4. 0. 3000 | |Oct 2001 |Windows XP |NT 50102600 | |Mar 2003 |Windows XP 64-bit Edition 2003 |NT5. 2. 3790 | |Apr 2003 |Windows Server 2003 |5. 2. 3790 | |Apr 2005 |Windows XP Professional x64 edition|NT50203790 | |Jul 2006 |Windows Fundamentals for legacy PCs|NT 5. 1. 600 | |Nov2006(volume licensing January |Windows Vista |NT6. 0. 6001 | |2007 retail) | | | |July 2007 |Windows Home Server |NT5. 2. 4500 | |Feb 2008 |Windows Server 2008 |NT 6. 0. 6001 | Features:- The features of MS-Windows are summarized in following points: 3. 2. MS-DOS:- Introduction:- MS-DOS (short for Microsoft disk operating system) is an operating system commercialized by Microsoft. You read "Computer Operating System" in category "Papers" It was the most commonly used member of the DOS family of operating system and was the main operating system for computer during 1980s. Several variants of DOS are available including Microsoft version dos (MS-DOS), IBM’sversion (PC-DOS), and several others. It is a single user and single-processor operating system that uses a command line interface known as DOS prompt. There are several levels to DOS. At the lowest level are the Bios (Basic Input/output system) which are responsible for managing devices like Keyboards and disk drives . The next level provides a set of higher level services implemented using the low level BIOS services; one can refer to disk drive1as â€Å"drive A:†and instead of referring to specific sectors or tracks we can refer to files by name (example LETTER. TXT). This layer of the system is implemented by another file which is loaded when the system starts up (the file is called MSDOS. SYS on MS-DOS systems, and IBMDOS. com on PC-DOS systems). The third layer is the command interpreter (or shell), which is what most people think it as DOS. This is contained in another file called COMMAND. COM, which is just an ordinary program that is started automatically. The shell job is to display a command prompt on the screen as to type commands. Applications are executed at the top of the shell. [pic] Fig: Logo of MS-DOS History:- MS-DOS (short for disk operating system) is an operating system commercialized by Microsoft. It was the most commonly used member of the DOS family of operating system and was the main operating system and was the main operating system for computer during 1980s. It was based on the Intel 8086 family of processors, particularly by operating systems offering a graphical user interface. It was known before a QDOS (Quick dirty operating system) and 86DOS. MS dos was originally released in 1981 and had eight major versions released before Microsoft stopped development in2000. It was the key product in Microsoft’s growth from a programming languages company to a diverse software development firm, providing the company with essential revenue and marketing resources . It is also used in GUI operating system such as windows as basic operating system. Versions:- i) MS- DOS2. 11 ii) DR-DOS5 iii) DR-DOS5. 0 iv) DR-DOS6 v) MS-DOS5. 0 vi) MS-DOS8 vii) MS-DOS6. 0 viii) MS-DOS6. 20 x) MS-DOS6. 21 x) MS-DOS6. 22 Features:- i) Files are organized into directory. ii) File name has extensions. (For e. g. TXT for text file). iii) File name can be of 8 characters long. iv) Native file system of DOS is FAT32 or FAT16. 3. 3. Linux:- [pic] Fig: Logo of Linux Introduction:- The term Linux is actually referred to mean a kernel of UNIX like operating system developed by a finish soft ware architect Linus torvald. The name Linux is derived from linus and unix. The Linux kernel is an operating system kernel used by the Linux family of Unix-like operating systems. It is one of the most prominent examples of free and open source software. Torvalds originally used Minix on his computer, a simplified kernel written by Andrew Tanenbaum for teaching operating system design. In April 1991, Linus Torvalds, a 21-year-old student at the Helsinki, Finland started working on some simple ideas for an operating system. He started with a task switcher in Intel 80386 assembly language and a terminal driver. , Linus However, Tanenbaum did not support extensions to his operating system, leading Torvalds to write a replacement for Minix. Linux started out as a terminal emulator written in IA-32 assembler and C which was compiled into binary form and booted from a floppy disk so that it would run outside of any operating system. The terminal emulator was running two threads: one for sending and one for receiving characters from the serial port. When Linus needed to write and read files to disk, this task-switching terminal emulator was extended with an entire file system handler, and after that gradually evolved into an entire operating system targeted at POSIX-compliance. Linus implemented enough POSIX system calls to make Linux run the Bash shell and after this bootstrapping procedure the development rapidly speed up. Although a running Minix system was originally necessary in order to configure, compile, install and run Linux, the Linux system quickly surpassed Minix in functionality and was soon able to boot on its own and compile its own source code. Linux is written in the version of the C programming language supported by GCC (which has introduced a number of extensions and changes to standard C), together with a number of short sections of code written in the assembly language. Versions:- |Versions |Date of release | |0. 01 |September 1991 | |0. 02 |October 1991 | |0. 11 |December 1991 | |0. 12 |February 1992 | |0. 95 |March 1992 | |1. 0. 0 |14 March 1994 | |1. 2. 0 |March 1995 | |2 |9 June 1996 | |2. 2. 0 |25 January 1999 | |2. 4. 0 |4 January 2001 | |2. 6. |17 December 2003 | |2. 6. 32 |3 December 2009 | |2. 6. 31 |9 September 2009 | ? Due to Version 2. 6. 31, Linux became the first operating system kernel to support USB 3. 0. Features:- ? It posses GUI as well as CUI Versions. ? It is more popular in networking server ,internet service provider as it consumes less space and fast to operate ? It is open source and available free of cost. 3. 4. Mac :- [pic] Fig: Logo of Mac OS Introduction:- On January 24, 1984, Apple Computer Inc. (now Apple Inc. introduced the Macintosh personal computer, with the Macintosh 128K model, which came bundled with the Mac OS operating system, then known as the System Software. The Macintosh is often credited with popularizing the graphical user interface. The Mac OS has been pre-installed on almost every Macintosh computer ever sold. The operating system is also sold separately at Apple retail stores, and online. The original Mac OS was partially based on the Lisa OS, previously released by Apple for the Lisa computer in 1983. It was the first Graphical User Interface (GUI) based Operating system. It was more user friendly and had a high quality graphics. It is more popular in graphical designing, animations and audio and video processing. Apple marketed its operating system software as â€Å"Mac OS†, in the beginning of 1997. The computer manufactured by Apple Macintosh Inc. needs operating system manufactured by itself otherwise it does not work. Apple was very strong in advertising their newfound machine. After it was created, the company bought all 39 pages of advertisement space in the Newsweek magazine, 1984 November/December edition. Apple was so successful in its marketing for the Macintosh, that it quickly outshone its more sophisticated predecessor, the Lisa, in sales – so much so that Apple quickly developed a product called MacWorks which allowed the Lisa to emulate Macintosh system software through System 3, by which time it had been discontinued as the re-branded Macintosh XL. Many of Lisa’s operating system advances would not appear in the operating system until System 7. Versions:- |System Version |Release Date | |1. 0 (. 7) |January 24, 1984 | |1. 1 |May 5, 1984 | |2. 0 |April 1985 | |2. 1 |September 1985 | |3. 0 |January 1986 | |3. 1 |February 1986 | |3. |February1986 | |3. 3 |January 1987 | |3. 4 | | |4. 0 |March 1987 | |4. 1 |April 1987 | |4. 2 |1987 | |4. |1988 | |6. 0 |April, 1988 | |6. 0. 1 |September 19, 1988 | |6. 0. 2 |Late 1988 | |6. 0. 3 |March 7, 1989 | |6. 0. |September 20, 1989 | |6. 0. 5 |March 19, 1990 | |6. 0. 6 |October 15 ,1990 | |6. 0. 7 |October 16,1990 | |6. 0. 8 |April, 1991 | |6. 0. L |Late 1991/Early 1992 | |7 |May 13,1991 | |8 |July 26,1997 | |9 |October 23,1999 | |X |1999 | Features:- ? It is GUI based operating system. It provides multiprocessing capabilities. ? It is used mostly in graphics designing field, animations, audio-video processing due to its high quality graphics. 5. UNIX:- [pic] Fig: Logo of UNIX OS Introduction:- It was developed by a team or group of programmers at Bell Lab (ATT). It was developed in the early 1970s. It is open source and free of cost. UNIX (officially trademarked as UNIX, sometimes also written as Unix with small caps) is a computer operating system originally developed in 1969 by a group of ATT employees at BELL Labs. Today the term UNIX is used to describe any operating system that conforms to Unix standards, meaning the core operating system operates the same as the original Unix operating system. Today’s UNIX systems are split into various branches, developed over time by AT as well as various commercial vendors and non-profit organizations. As of 2007, the owner of the trademark is The Open Group. During the late 1970s and early 1980s, the influence of UNIX in academic circles led to large-scale adoption of UNIX by commercial startups. The term â€Å"traditional Unix† may be used to describe a UNIX or an operating system that has the characteristics of either Version 7 Unix or UNIX System V. As of 2007, the owner of the trademark is The Open Group, an industry standards consortium. Only systems fully compliant with and certified according to the Single UNIX Specification are qualified to use the trademark; others are called â€Å"UNIX system-like† or â€Å"UNIX-like†. During the late 1970s and early 1980s, the influence of Unix in academic ircles led to large-scale adoption of Unix (particularly of the BSD variant, originating from the University of California, Berkeley) by commercial startups, the most notable of which are Solaris, HP-UX and AIX. Today, in addition to certified UNIX systems such as those already mentioned, Unix-like operating systems such as Linux and BSD are commonly encountered. Versions:- †¢ Andran †¢ UNIX/32V †¢ UNIX4 †¢ UNIX5 †¢ UNIX6 †¢ UNIX 7 †¢ UNIX8 †¢ UNIX9 †¢ UNIX10 Features:- ? UNIX operating systems are widely used in both servers and workstations. ? UNIX was designed to be portable, multi-tasking and multi-user. As it is CUI based it is fast and consumes less memory space. ? It is multiuser and multitasking operating system. ? It is open source and free of cost. 6. Sun Solaris;- [pic] Fig: Logo of SUNSOLARIS Introduction:- It was developed by Sun Microsystems during 1990s. Sun Microsystems. Inc. is a multinational vendor of computers, computer components, computer software, and information technology services, founded on February 24, 1982. The company is headquartered in Santa Clara, California (part of Silicon Valley), on the former west campus of the Center. It is the modification of UNIX operating systems. It is used in large Internet Service Provider (ISP), large banks, Telecommunications. etc. It manufactures its own computer and installs its own software. They are used for large amount of data processing. They are highly expensive . They are much more fast and efficient than personal computers we use. It is used in large servers. [pic] Fig: logo of Sun Microsystems 4. Summary:- The operating systems are the set of programs that control the entire operation of computer. Operating systems make the computer work. The operating software is the one to make other software work. It provides a platform for users and other software to work. The operating system should be choosed on the basis of one’s need and how the user wants programs to work. We should also focus on the user friendliness of operating system. We should choose operating system on the basis of its cost to operate and its compatibility with other programs. The Microsoft windows are used in huge number as operating system rather than other operating systems due to its simplicity and easy access. [pic] ———————– 13 How to cite Computer Operating System, Papers