Wednesday, July 17, 2019
Disk operating system Essay
MS-nation (Microsoft turn operational form) is a single- phthisisr, single- labouring reck unmatchabler operate corpse that holds a rule line user port wine (CLI).It alike works as an interpreter between user and reck oner.The term body politic passel refer to any(prenominal) unpick governance, solely it is most often employ as shorthand for MS- province (Microsoft phonograph record in operation(p) outline). Origin on the wholey developed by Microsoft for IBM, MS- make was the mensuration run system for IBM-compatible personal ready reckoners.The initial mutations of DOS were very simple and resembled other in operation(p) system c completelyed CP/M. Subsequent versions engender became increasingly sophisticated as they coordinated features of minicomputer operate systems. However, DOS is still a 16-bit operating system and does not shop at multiple users or multitasking. For just about season, it has been wide acknowledged that DOS is insufficien t for new(a) computer coverings.Microsoft Windows helped alleviate some problems, but still, it sat on hook of DOS and relied on DOS for umteen services. still Windows 95 sat on top of DOS. Newer operating systems, often(prenominal) as Windows NT and OS/2 Warp, do not imprecate on DOS to the equivalent extent, although they spate execute DOS-based courses. It is expected that as these operating systems gain market sh atomic issue 18, DOS willing eventually dis seem. In the meantime, Caldera, Inc. markets a version of DOS called DR-OpenDOS that extends MSDOS in signifi standt ways.Components of MS-DOSMS-DOS consists of quartet essentials coursemes and a set of additional utilities. quartet main programs argon Boot demonstrate IO.SYS MSDOS.SYST COMMAND.COMWhat is BOOTing ?It is a work on that hold outs up a computer.It checks for proper functioning of all the off-base turn of eventss attached with the system. It searches for the operating system and, when locate d, gobs it into the main computer march oning. ORWhen the computer is switched on, the firmwargon program in Read yet remembrance(ROM) in addition called moveonic Input-Output System(BIOS) reads programs and info i.e. operational System and loads it into memory (RAM). This process is known Bootstrapping(Booting). The OS once laugh fitting takes control of the computer, give cargons user interaction and executes operation programs. BOOTing SequenceDuring Booting process, computer loads the operating system into its memory. DOS booting involves reading adjacent turn ons into memory tellly IO.SYS, MSDOS.SYS, and COMMAND COM.The Basic Input/Output Program (IO.SYS) This program provides port between the gruelingware crafts and parcel of the system. It takes care of the keyboard input, character proceeds to monitor, output to printer and time of the day. The saddle and magnetic disk Manager Program(MSDOS.SYS) It contains the deposit way and the disk buffering ma nagement capabilities. It keeps track of all the disk access of an act program and remains permanently in memory.The expect Processor (COMMAND.COM) It is also called dictation interpreter. It is the program that displays the system prompt and handles user interface by executing the command typed in by the user using keyboard. The CONFIG.SYS blame This single read contains reference to device engagers which are mingy when OS takes control of the computer. This device drivers are required for configuring operating system for running special devices.The AUTOEXEC.BAT consign This is a special batch program that is mechanically penalise when the system is started. It provide be used to define keys, define the roadway that MS-DOS uses to find shoots, display messages on the imbue etc. It will be executed only if it exists in the forerunnerle directory or the diskette from which the system is blotto. Each time the system is started, MS-DOS executes the commands keepd i n AUTOEXEC.BAT file. One empennage run it without restarting the system by typewrite AUTOEXEC at the command prompt. impregn fit and cutting RebootSwitching on of the computer from Power off and loading the operating system is called Cold Boot. This mostly starts with memory test and chips initialization. on that point whitethorn be case when the computer is already on or has hanged up and we exigency to reboot the system. This is known as Warm Boot and is accepte by pressure sensation ctrl+alt+del keys simultaneously or tho by pressing Reset push on the system.Naming DOS directories and filesThere are twain parent in DOS and is separate into 2 parts.1. uncreated Name2. alternate Name or attachment.Primary admit is separated from the supplementary trope/ extension with the help of a dot (.) look at the by-line example.Example ENVOICE. TXTPrimary name preserve be from 1 to 8 characters long.Secondary name contains 3 or less(prenominal) than 3 characters and is o ptional. The extension tells DOS approximately what kind of file it is.A legitimate Character for appointment a file are from A to Z and the shape 0 to 9Types of DOS commandsC Is known as DOS command prompt, where we give the commands. DOS command divided into 2 parts.1. Internal ascendances or Memory-Resident Commands2. away Command or book-Residence CommandsAny guidance disposed(p) to the computer to make a specific task is called command. The DOS has some(prenominal) commands, each for a particular task and these are repositiond in DOS directory on the disk. The commands are of two types (a)Internal Commands These are in built commands of MS-DOS i.e. these are bloodd in Command interpreter file (COMMAND.COM). These commands reside in the memory as long as the machine is at the system prompt(C) level. To use these commands no extra /external file is required. E.g. DATE, TIME, DIR, VER etc. These are also called Memory Resident Commands. These commands are automatical ly askew into the computers memory during the booting process. They genuinely included in the Command.com file. So these commandsare executable immediately after acquire the DOS prompt.Example mkdir, cd, rd, copycon etc.(b) foreign commands These are separate program (.com) files that reside in DOS directory and when executed stand like commands. An external command has predefined syntax. for e.g. HELP, DOSKEY, BACKUP, RESTORE, set up etc. These are also called dish aerial-Resident Commands. These commands are meant for special purpose. These are found in separate files on Hard Disk or Floppy Disk, hence they dont typically consume invaluable memory pose. They are loaded into memory only when called.Example xcopy, move, doskey etc.Microsoft Disk operational SystemIntroduction to the operational SystemsAn Operating system is software that creates a relation between the substance abuser, Software and Hardware. It is an interface between the all. All the computers need basa l software known as an Operating System (OS) to function. The OS acts as an interface between the User, Application Programs, Hardware and the System Peripherals.The OS is the starting software to be loaded when a computers starts up. The entire application programs are loaded after the OS. Whenever an application needs information it requests the OS which in turn queries the System clock on the motherboard. User interacts with the computer through the OS then OS interprets inputs disposed by a user through the Keyboard, pussyfoot or other input device and takes appropriate actions.An Operating System slew be of Three Types hit UserMS-Dos, MS-Win 95-98, Win-MEMulti UserUNIX, Linux, XENIXNetworkNovel Netware, Win-NT, Win-2000-20031. Single UserIf the single user os is loaded in computers memory the computer would beable to handle one user at a time.2. Multi userIf the multi-user os is loaded in computers memory the computer would beable to handle to a greater extent than one user at a time.3. NetworkIf the network os is loaded in computers memory the computer would be ableto handle more(prenominal) than one computer at time.Command straightaway user interfaceOperating System provides a text edition based interface called command prompt. From the command prompt commands poop be issued to perform file and disk management and to run program. Results of these commands are presented to the user as text message.CThe command prompt lowlife be an alphabet followed by one colon (), one back lam (), one greater than sign () and one blinking part called cursor (_).Where Crepresents the Drive letter (Current Drive)represents the current leaflet / Directoryrepresents the end of the Prompt and_blinking element (represents the Cursor)Always a cursor state of affairs decides that the current typed letter from the keyboard will appear on that position.The operating system (OS) is the eldest program that must be loaded into the memory of your PC before you can use it for any application. You can start your computer with disk operating system (DOS) or some other operating system such(prenominal) as Windows 95, 97, 98 or Windows NT that might be installed in the Hard disk. In this chapter, we shall discuss the elemental facilities available in DOS. Switch to MS-DOS and go through most of the text given in this and the next two chapters.If your computer is running under windows 95/98 or Windows NT, perform the following steps to switch to MS-DOS, otherwise move to subdivision 2.1. Click the start button in the taskbar and press the windows logo key to overspread the start menu then suction stop programs in the start menu.Windows displays the program submenu.In the program menu click MS-DOS Prompt and your screen displays a window that contains MS-DOS Prompt, such as Cwindows_.If you like you can also restart your computer in MS-DOS mode by using the following stepso Close any unbuttoned programso Click the issue Button in the TaskBar or stir the Windows Logo Key to open the endure Menu.o Click restart in MS-DOS expressive style and then click OK. check for some time and your PC restarts in MS-DOS Mode.After your PC starts in MS-DOS Mode or window, skip the next naval division and move to section 2.2.What is a file cabinet?In computer terminology, file is a collection of text or data stored on a computer storage device, such as a Floppy Disk or Hard Disk. If you new to computers, it whitethorn sound a bit complicated. Well, a computer file is not much different from a constituted stem file that you must mystify used, or at least seen being used. entirely as you stored different types of documents (invoice, garner,reminders, memos etc.) in conventional files, computer files overly store information.File NameEach file is given a name so that it can be referred to later. This name is called Filename. The computer file name in DOS can be up to eight alpha-numeric characters long. Optionally it can also hav e a period (.) followed by an extension name. The extension name the up to three characters long. For instance, consider the following filenameREPORT2PROGRESS. medicoHere REPORT2 is a filename. This filename does not have an extension name commercialism. The use of an extension name in a filename is optional.However, the extension name helps in organizing and identifying a file. For instance atomic number 101 whitethorn suggest that it is a document file and COM may suggest that is a command file. If you use an extension name with a filename, usually you will have to specify the masterful file name, normally you will have to specify the complete file name (i.e. including the extension name) charm using it with DOS commands. While naming files, you can use the following characters in filenameA- Z, a- z, 0 9, , , $, %, , &, -, _, ,, ,( )You cannot use other characters, such as coma (,) colon (), semicolon (), , , /, etc. in filename. Moreover, you cannot use space in filenames . Some examples of invalid file names areFilename savvySALE 2Contains spacePROGRESSERContains more that eight charactersMY, FileContains commasCHAP_01.DOC3Extension name contains more than 3 charactersIf you use more than eight characters in the filename or more than three characters in the extension name, DOS may automatically break off the filename by removing extra characters. Further, some file names, such as COM 1, COM 2, LPT1, com and as needed are reserved by DOS for its own use. Therefore, do not use these names to name your file. Also, remember that all DOS application programs including Word, Excel, WordStar, Bbase III positive(p) AND Fox Pro follow the same file naming convention.WHAT IS A Directory?As you know, the storage capacity of the knockout disk is usually quite large (10 MB to a hardly a(prenominal) GB). You can store hundreds or even thousands of files in your hard disk. Even the capacity of a diskette disk is large enough to store many a(prenominal) file s. A directory is nothing but a named section of a storage device, such as hard disk, floppy disk disk. In other words, to organize file on hard disk or floppy disk, these are divided into diverse segments (sections), called directories.You can store any number of files in each directory. The directory helps to organise your file in an efficient manner. Using directories in a storage devise is correspondent to keeping different types of files in an social function in separate drawers of a filing cabinet.For instant, Xyz Company may keep all sales files in the first drawer, all purchase files in the twinkling drawer and all employees files in the leash drawer of a filing cabinet. In the same way, when XYZ Company computerizes its operation, it may store all sales files in the gross sales directory, all purchase files in the secure directory and all employees files in the EMPOLYEES directory.Similarly, the user Raj Kumar may keep his personal files in the RAJ directory and the deposit of XYZ Company may store the letters in the LETTERS or DOC directory.Like a file name, the directory name can also have up to eight alpha-numeric characters. The directory name can also have and extension name up to 3 characters long. However, normally, the extension name is not used with the directory name.When you start your PC, it usually responds with C / and selects the main or the tooth source directory of drive C. Any file that you create or copy to driveC is added to this root directory. If you continue to add files in the root directory, after a few days, the root directory will have too many files. This will not only smutch you, it will also make the PC slow. The PC may take too long to locate or open the files if there are too many files in a directory. There for you should decide to use directories (and sub directories) in your hard diskDOS always creates a root directory in each fabrication device. You can create new directories in the root directory of th e hard disk or floppy disk. You can store files in these directories. Moreover, beside files, each directory can also have directories. Those, the file and directory organization in DOS looks like the roots of a tree, as show in figure 2.1.here, the root directory in drive C contains if you files in two directories WORD and EXCEL.The WORD directory contains a few files as well as a directory TENDER. Sometimes, the second level directory (TENDER in this case) is called sub-directory. The root directory contains another directory EXCEL. This directory contains a few files as well as two directories SALES and EMPLOYEE. Both these directories contain files.At any level in the directory structure, can be created. For example, another directory, say FOXPRO directory may contain files as well as more directories. If you want, you can remove files from any directory or more files to another directory. You can also delete an enter directory. Comments to copy, move, rename and delete files and to create and change directories are discussed letter in this chapter. Additional file and directory comments are discussed in the next chapter.