Abstract:This project is a package, which user interact with icons rather than typing commands.A user interacts with the Operating System(OS) through a shell. This interface to the OS can be either textual or graphical. In textual approach the user is required to type commands, which are then interpreted by the shell and an appropriate action is taken. In a graphical OS interface much of the functionally of the OS is  displayed on the screen. This is accomplished by using small symbols called ‘icons’, which represent certain OS functions. In other words, ‘icons’ are symbolic representations of the function they are tied up to. Whether a graphical OS interface is better or a textual OS interface is often debatable. And more often than not it is a matter of taste and choice. As a seasoned programmer, it might not appear very sensible to have attractive icons on the screen-some depicting the activity of renaming files, some deleting files, and so on. But look at it from the user’s point of view. A normal user is more interested in the convenience of the finesse of the program he is using, than the hard work that has gone into the development of the program. He prefers visual pictures to textual commands-pictures which he can easily relate to and understand, rather than memorizing commands. This is where the Graphical User Interfaces(GUIs) score. Thus, the underlying principle of any GUI is very simple-not only do pictures communicate, but sometimes they say it better than words. GUIs were first introduced by Apple on its Microcomputers, and lately by Microsoft Corp. on IBM compatibles under the name Windows.

2. SYSTEM ENVIRONMENT:

          a). Hardware Configuration. 

          b). Software Configuration. 

a). HARDWARE CONFIGURATION:  

 Processor  :  PENTIUM III

           Clock Speed                            :  866EB MHz 

          RAM                                       : 128.0MB

           Hard Disk                               : 20GB

           Floppy Disk                            : 1.44MB(3.5’)

           Monitor                                   : SVGA Color Monitor

      Key Board                               :  104 keys

     Printer                                     : HP LaserJet 

b). SOFTWARE CONFIGURATION:

         Operating System                   : MS-DOS

         Programming Language        : C

About operating system:

          Operating System software is a class of programs which manages the resources of the computer, process commands, and controls program execution. As the foundation of the all computer operation, it is the most complex program executed on the computer, yet must also be the  most reliable.

Functions of operating System.

Any Operating System must perform three basic roles:

(a).    As a “manager”, the Operating System determines who will use the printer, disk, VDU, key board and other peripheral units and when they will use them. When an error is discovered, the operating system reports the error to the user. The OS also manages the use of memory, controls timing of events, and controls the priorities of various requests. 

(b).    As a “command processor”, the OS reads the commands from the user, verifies their accuracy, loads what is needed from the disk and initiates the execution of the user command. 

(c).    As a “controller”, the  OS, at least to some extent, must always be in control of the system resources. If a program crashes from any type of error, control should return to the OS, which then determines the type of error.

An Operating System can be Single User OS, Multi User OS or a

Multitasking OS. 

A Single User OS caters to a single user and all resources are available to this user at all times. Microsoft Disk Operating System (MS-DOS) is one such OS.         

A Multi User OS is one that supports several users at a time. Most OS’s for minicomputers and mainframe computers are multi-user OS. UNIX and XENIX are the popular Multi User OSs.

           A multitasking OS is the one that supports the several task at a time, but only a single user. Windows and OS/2 are examples for Multitasking Oss.

Some thing about MS-DOS:

A small history:

          In the early eighties when 8080 based 8-bit computer was in use, it was being run on an OS called CP/M-80 or Control Program for Microcomputers. It was written by Gary Kildall of Digital Research Corporation. It soon became the worlds fastest selling OS.

    When IBM decided to enter the minicomputer market, they decided to base their computer on Intel’s 8088 microprocessor. IBM contacted with Digital Research and Microsoft, neither of which had 16-bit OS. Then Tim Patterson of Seattle Computer Product had written a 16-bit of OS called 86-DOS.

          Microsoft purchased 86-DOS from Seattle Computer Products and reformed as MS-DOS version 1.0.

 The Kingdome of DOS:

           The OS used on 8086 family microprocessors comes in two parts: 

(a).    ROM software.

(b).    DOS software.

           Out of this ROM software is chip based. That is, the programs, which form the ROM software, are hard wired into the chips at the time of manufacturing, and hence cannot be modified or erased.

           DOS software is disk based. That is the program belongings to the DOS software are present on the disk in the form of files.

(a). ROM software.

          Software plays a vital role in the operation of computer. If some part of the software that is frequently needed  and is utmost importance for any computer, it is permanently built into the computer. It leads to computer operations becoming easier and efficient. And that is what the ROM program is all about.  

It consists of number of functions , called as routines. These can be divided into four types,

 1.      ROM startup routine.

These do the work of the computer getting started.

 2.     ROM-BIOS routine.

 This is the collection of routines, which provide support services for the continuing operation of the computer.

 3.     ROM extension routine.

 These are the program that are added to the main ROM when certain optional equipment is added to the computer.

4.     ROM BASIC routine.

 These provide the core of the Basic Programming Language.

 (b). DOS software.

             The DOS  software divided into three parts which are stored in three different files on a disk( floppy or hard disk). The disk which contain all three files  are called as bootable disk.

           The three files are,

           1.      IO.SYS

2.     MSDOS.SYS

3.     COMMAND.COM

 1.      IO.SYS.

This file contains two important modules.

1). Device drivers

2). SYSINIT module which loads the file MSDOS.SYS from   the disk into memory.

2.     MSDOS.SYS

 This file is also called as DOS kernel. This kernel will do four major roles:

a). Process Control

b). Memory Management

c). Application Program Interface.

d). File Management System.

3.     COMMAND.COM

 This file contains the command processor,best known as shell. It is the user’s interface to the Operating System.