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MS-DOS
Computer FilesIn an organization, various files are
maintained like employee file, client file or purchase file etc.
Similarly, a computer hard disk contains various files such as textual file, graphics file etc.
Every file is given certain appropriate names.
Continued…A file name should be descriptive and
meaningful.A file name can have two parts:
Primary nameExtension
And generally they are separated with the help of a dot.
Continued…A primary name can have a maximum of
eight characters while an extension can have maximum of three characters.
A file name is valid even without an extension.
Extensions help in identification of files.File names should be valid.
MS-DOS/PC-DOS/DOSIt is non graphical, line-oriented command-
driven operating system having simple interface and non friendly environment.
User can type the commands either in upper case or in lower case but DOS interprets/stores everything in upper case letters.
Continued… If you boot the system from hard disk drive by
default the prompt that you find in DOS looks like
C:> If you are booting from floppy drive then
prompt will look likeA:> or B:>
If you are booting from optical disk drive or CD then prompt will look like
E:>
Let’s define DOS nowIt is an interpreter, that provides a linkage(interface) between electronic circuitry and program.
It is a program loaded into the memory of user’s PC before execution of any application.
It creates an environment for managing the resources and execution of any program having extension .exe,.com,.bat
More about DOSIt is a single user operating systemThe core of DOS is contained in three files,
IO.SYS, MSDOS.SYS and COMMAND.COMThe disk that contains all the three files is
called a Bootable disk or Startup disk or simply DOD disk.
Bootstrap procedureAfter the system unit is switched on , a
search is made on A drive for DOS software, if it is not available it is searched on the hard disk. Then it is loaded automatically.
Important NoteA floppy disk or hard disk is divided into
concentric circles called tracks. These tracks are further sub divided into sectors. The boot sector is the first sector on the disk.
IO.SYS
MSDOS.SYS
COMMAND.COM
IO.SYSIt has two main parts:
-To verify the various input and the output devices. All drivers together called DISK BIOS.-Another part is SYS.INI which loads the file MSDOS.SYS from hard disk into memory and it becomes a memory resident program.
MSDOS.SYSProvides a link between BIOS and user’s
application program.Provides the facility of isolating the program
from the physical aspect of the system and intricacies of the hardware
Continued…It provides the following functions:
-Process Control-Memory Management-Application Program Interface-File management System
COMMAND.COMIt is divided into two portions:
-Resident portion-Transient portion
DOS commandsDOS commands are divided into two parts:
Internal CommandsExternal Commands
Internal CommandsThese commands are automatically loaded in
the memory when DOS is loaded in the memory.
These commands cannot be seen with the help of DIR command.
They are easy to learn and operate.
Continued…CLSDIRDATETIMEVOL VERCOPY CONTYPE
MDCDRDPATHCOPYPROMPTRENDEL
Continued…CLS – To clear the
display screenC:\>CLS
DIR – To display list of directories, sub directories and files.C:\>DIR
DATE – To display the system’s current date and new date can be entered. C:\>DATE
Continued…TIME – To display the
current system’s time and new time can be entered. C:\>TIME
VOL – To display the volume label or name of the volume given by the user to a disk and to check the volume name given by the label or format command. C:\>VOL
Continued…VER – Displays the
current/installed version of DOS on the system. C:\>VER
COPY CON – To create the file. C:\>COPY CON Table^Z1 file(s) copied
Continued…TYPE – To display the
contents of the file. C:\>TYPE
REN – To rename old file name with new file name. C:\>REN abc xyz
DEL-To delete the single file,multiple files can be deleted by using wild cards. C:\>DEL table.exe C:\>DEL *.*
Continued…MD – to create a directory
or sub directory under the current directory. C:\>MD fan
CD – to change from one directory or sub directory to another directory or sub directory. C:\>CD.. C:\>CD fan
RD – to remove a directory or sub directory and it should be empty before deleting it. C:\>RD fan
Continued…PATH- To provide
access to the files located in other directory paths or disk. C:\>PATH=D:\AC;
COPY-To copy one or more files to another disk with same filename. C:\>COPY E:*.* D:\AC
External CommandsThese are not the permanent part of the
memory.To run these commands , external files are
required.These are used for relatively complex jobs
like copying an entire diskette into another, sorting a disk etc.
Continued… EDIT ATTRIB BACKUP RESTORE CHKDSK DISKCOPY DISKCOMP DELTREE DOSKEY FORMAT FDISK
FIND LABEL MORE MODE MOVE PRINT SCANDISK SORT SYS TREE POWER
Continued…Edit- -To execute EDIT.COM is
required.-This file utilizes 413KB
space of memory.-Edit program is a full
screen editor.-Purpose is to create a
new file or modify the contents of an existing file.
- Syntax is C:\>EDIT filename.extension
ATTRIBATTRIB:- To execute
ATTRIB.EXE file is required
- Utilizes 11,208 KB space in memory.
- Purpose is to change the attribute of a file.
- Syntax is C:\>ATTRIB filename C:\>ATTRIB fan +H+R
Attributes- Attributes+R - Read only-R - To remove read
only+H - To hide the file-H - To unhide a
hidden file+A - To set the file
Archival-A - To reset the file
Archival+S - To set the system
file-S - To reset for
system file
Backup CommandBack Up- Used to copy the
various files from the hard disk or floppy to create backup disk.
- The file required is BACKUP.EXE
- Covers 35,715 KB for its storage
- Syntax is C:\>BACKUP Source path options Target path
Options /S – to copy all
subdirectories of source path /M – to copy all files of
source path which are modified since last backup.
/A – to copy files to the target disk without erasing the target disk. Without this option Backup command erases all files of target disk.
/D - to copy files saved on or after given date
/T – to copy files saved on or after given time.
/F – to format the target disk before doing backup.
/L - Creates a file containing time and date of backup files.
C:\>BACKUP C:\DOS A:/S/L
RestoreUsed to restore files
copied by backup command.
File required for this command is RESTORE.EXE.
Space required for this is 38342 Bytes.
Syntax is C:\>Restore Source path Options Target path
Options /S – to restore all files from all
subdirectories. /P – to prompt before restoring
files that are read only and which are changed since the last backup.
/B - to restore all files on or before the given date.
/A - to restore all files on or after the given date.
/E – to restore files on or earlier than given time
/L – to restore files on or later than given time.
/N - to restore files that are no longer exists on destination disk.
/D – to restore files which match given specification on the backup disk.
Example:- C:\>RESTORE B: C:/S
CHKDSKRequires CHKDSK.EXE
fileTakes 12,241bytes for
storage.Returns the configuration
status of the selected disk.
Returns volume serial number, total disk space, space in hidden files, space in directories, space in user files, space available on disk, number of bytes in each allocation unit, total number of allocation units, available number of allocation units, total memory and free memory.
Syntax is C:\>CHKDSK drive name
DISKCOPYRequires
DISKCOPY.COM file.Uses 13,335 bytes of
storage.Used to make duplicate
copy of the disk like xerox copy. It formats the target disk and then copies the files by collecting files from the source disk and copies to the target disk
Syntax is C:\>diskcopy <source path> <destination Path>
DISKCOMPRequires DISKCOMP.
COM file Covers 10748 bytes of
storageTo compare the disksTo find out they are
identical or notIf we will try to compare
two dissimilar disk it will display an error message.
Syntax is: C:\> DISKCOMP <<source disk path>> <<target disk path>>
DELTREERequires
DELTREE.EXE fileSpace required is
11111 bytesUse to delete files
and directoriesSyntax is C:\>
DELTREE <Path>
FINDRequires FIND.EXETakes 6770 bytes for its
storageUse to search files stored
on the disk and data stored in the files
Syntax is C:\> Find “text” <filename>
C:\> DIR|FIND “filename”/C- returns number of
lines containing specified text
/I- ignores upper case and lower case
/N- displays number of lines that contains the specified text
LABELRequires LABEL.EXE9390 bytes for its
storageUsed to see volume
label and to change volume label
The label should be maximum of 11 characters.
Syntax is C:\> Label <Drive Name>
PrintRequired PRINT.EXE
file and 15656 bytes for storage
Used to print the filesFiles must be
standard text files and containing data compatible to the printer.
Syntax is C:\> PRINT <Filename>
DOSKEYRequires
DOSKEY.COMIt takes 5861 bytes of
storage mediaUsed to display the
history of the DOS commands typed by user using the keyboard.
It stores number of commands in memory buffer according to its size.
FormatRequires FORMAT.COMRequires 22974 bytes
Use to make disk usable for operating system by dividing the disk into magnetic tracks and sectors
Number of sectors and tracks depends upon capacity of the disk and dos version
Syntax is C:\> format <drivename>
FDiskRequires FDISK.EXE
and requires 29336 bytes
It is used to make a fixed disk for use
To make partition of high capacity fixed disk and can organise cylinder on it to store the data
Syntax is C:\> FDISK
MoreRequires MORE.COM
file and 2545 bytes for storage
It is a filter command like find and sort, to see the contents of the file page by page
Used with dir and type command
Syntax is C:\> More <file name>
C:\> Type <filename>|more