DOS (Disk Operating System)

DOS, which is either an acrostic or an acronym of Disk Operating System, is an operating system solely and completely relies or depends on the use of the keyboard of all its activities. A dos command is an instruction that is entered into the computer for processing; and a Parameter is an additional specification that is entered after a command. E.g. DIR C: DIR=command, C: = parameter The DOS prompt is an indication that the system is ready to accept a command by the display of a blinking cursor. The command syntax refers to the specific rules that govern the way instructions are entered at the prompts. DOS FILES: There are two main types of DOS files and these are Internal Command Files that contain internal command instructions which mostly remain in RAM at all times because they are frequently used by DOS and the other software application programs. Most of these internal Command files use Command.com file to store their instructions. The other DOS files are the External Command Files, which are stored on the disk until needed to perform specialized tasks. External command files has one of these extensions .COM, .EXE and the .BAT Therefore, beside the Command.com, Autoexec.bat had Config.sys files are created the user to automatically execute certain commands whenever the computer boots. A file is made up of related records whilst a record is constituted by either one or more fields. A field is a group of related characters. Whilst a character is made up of 8 bits (1 byte) representing an alphabetic letter, a numeric figure or a special symbol. And finally a bit is a contraction of binary (base 2) digit, which is either 1(on) or 0 (off) in computer data representation. All files are kept in the directory. The 3 types of directories are the Root Directory that mostly refers to the default or current disk driver. E.g. A> or C>: the folder or main directory or subdirectory which is created within a folder. An example is C:>WINDOWSW98, C:> is the Root Directory. WINDOWS is the Folder or Main directory and W98 is the subdirectory within the WINDOWS folder. The AUTOEXEC.BAT file is used to load certain programs into the RAM when the computer is booted. For example to display automatically or auto-display a menu or any program, the appropriate load commands needs to be stored in the AUTOEXEC.BAT file. The CONFIG.SYS file stores special configuration information required to run certain software programs. For example, to use Database packages, a command needs to be stored in the file which will designate how many files can be ‘open’, or accessed at once during processing.