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1. Introduction

2. Purpose of OS

DOS

3. Introduction to DOS

4. Files and directories

5. Hard and floppy disk

6. System commands

8. Networks command (2 - summary)

3. Hard disk and floppy in DOS

1. Diskettes and hard drives - 2. Directory commands - 3. Manipulation of files - 4. Commands for text files

A file is a set of information grouped under a single name. This can be an address list, a set of recipes from kitchens or even an executable program.

On DOS, a file that is stored on the disk hard (or a floppy disk) is designated by a name consisting of 1 to 8 digital - alphanumeric characters or special characters: $ & # @ ! % () - < > _

The file name is followed by an extension of 3-character maximum, spaces are prohibited between 2 letters. This extension is used to determine the file type.

DOS does not distinguish between uppercase and lowercase letters. Accented characters are prohibited.

Examples:

• abcdefghi.df is not valid more than 8 characters in the name but abcdefgh.fd is a valid name

• abcdefgh.HTML is invalid, extending over 3 letters, but abcdefgh (without extension is valid).

DOS implicitly recognizes some extensions:

• com: executable program
• exe: a programming language (compiled) from executable program
• bak: backup file
• $$$: temporary file created by a program
• bas: basic language file
• bat: batch, a set of lines of DOS commands
• sys: System file reserved for the DOS configuration for devices

Others are used by convention:

• pas: program written in pascal, non-executable
• C: program written in C, non-executable
• DOC: document text (documentation)
• TXT: text file
• ini: used for the initiation of programs files (depending on the syntax of the programmer).

Doc and .txt files are often used on the installation disks, and file read.me (English) or lisez.moi (french) such as documentation or solution during the installation. These are text files.

1. Hard disks and floppy disks

DOS automatically recognizes the hard drives and floppy disk drives if they are detected by the BIOS. A CD-Rom drive requires additional drivers. A hard disk or floppy disk must first be prepared using the DOS Format command.

Capacities are expressed in Byte. For 1024 bytes, known as Kilo (KB or KB), for 1024 kilograms, one speaks of Mega (MB or MB).

Floppy drives are the letters "A:" and "B:". The first partition of the hard drive is as "C:", the other partitions are the following letters. To switch from one drive to another, simply type the letter followed by 2 points.

The organization of the data on the hard drive (to a lesser extent the floppy) is done by directories and subdirectories. These directories can gather the data in specific boxes. When you read data on a hard disk, you start by the ROOT, this is the top directory of the disk. It contains data and directories. The command to display the files in the current directory is DIR

Example: the C: disk contains:

• Autoexec.bat: bootable Dos batch file
• config.sys: System configuration file read at startup
• ...
• DOS <DIR>: directory containing the operating system-specific files. A DOS directory DIR command displays
• QBasic.exe: basic program...
• mouse <dir>
• ...

2. Commands directory

Without going into the details of these commands, we will move one directory to another, create and delete, view the content.

1.1 DIR (internal control).

Example, we are in the main directory of the hard drive C: (that shows us the prompt DOS displaying c:\>).

c:\>dir <Enter>

Directory of C:\

COMMAND COM      47845     09/04/91  5:00

AUTOEXEC BAT            336    08/09/92   22:02

CONFIG SYS                 670   08/09/92   20:19

DOS             <DIR>               07/09/92   15:44

UTILS           <DIR>               07/09/92 16:14

5 file (s) 48851 bytes

30599168 bytes free

The information displayed is for the file: the name and the extension, the size in Byte (octet), the date and time of change. For directories, type (<DIR>) and the date of modification.

When the number of files to display is too large, part of the information scrolls without being visible to the user. Two options are available:

the space between the command and the optional characters can be omitted.

It is also possible to only display files that meet certain criteria using masking and replacement characters.

Example:

c :>DIR *.sys displays only files with extension sys.

c :>DIR conf*. * displays all files whose name begins with conf, regardless of the extension.

c :> DIR *.?at displays all files that have the extension terminated at, for example bat files.

2.2 CHDIR or CD in abbr.: internal command

Example: you are in the main directory of C: (the root). You want to move to the sub-directory DOS, type: c :> DOS 

In summary:

2.3 MKDIR (MD for short), internal command.

Example: c :> MD nothing creates the directory nothing in the root of C:

2.4 RMDIR (RD for short), internal command.

If the folder to delete is not empty, the command is denied. DOS displays a message to notify.

2.5 Tree: external control

The display is done in the form of tree

3. Manipulations files

Are included in this part the commands to run a program, delete, move, rename files. Create a file in dos through the use of a program. Backups on disks commands are included in a separate chapter.

3.1 Execution.

DOS supports 3 kinds of executable files directly following the extension:

• .bat: these are lists of DOS commands
• .exe
• .com

If the software is not in the current directory, we can start typing: name_disk:\directory\subdirectory\program. For example >c:\dos\tree

The Path that will be seen later command do not type the location for certain locations.

3.2 Copy: internal control

The change of location is accepted, as well as wildcards? and *. Unlike Windows, DOS will overwrite the destination file already exists without confirmation.

Examples:

> COPY autoexec.bat autoexec.sav

>COPY *.bat * .sav: copy all the file with a .bat extension to same name with the extension .sav files in the current directory.

>COPY c:\DOS\*.exe A:\*.exe: copies all files executable .exe from the DOS directory to the floppy disk.

In some cases, the . as:

>c:\DOS>COPY a:\rien.* will copy all files whose name is rien to current directory

The use of wildcard characters can sometimes cause a few problems.

c :> COPY c:\*.exe a:\rien.* is false. It copies all .exe files to a single file rien.exe. As the COPY command overwrites the destination file, only the last file will be copied.

The XCOPY command also copies directories

3.3 RENAME (REN for short): internal control

Permission of replacements characters is allowed. All the principles of the command COPY shall also apply. If the destination file already exists, it is overwritten.

3.4. DEL or ERASE: internal command

Wildcards are permitted but not desirable. The DEL and ERASE commands only offer no confirmation. 

3.5 UNDELETE: external (from DOS 5.0)

Note that this command is not as powerful as the Windows Recycle Bin. The location of a deleted file is left free for other files. It must be performed immediately after the deletion.

The use of wildcards ? and * are authorized.

3.6 COMP: external command

3.7 XCOPY: external command

This command is similar to the COPY command but also transfers the files included in the directories. It is still used in batch files.

4. Command for text files

Are included here some DOS commands specific for text files.

4.1. TYPE: internal command

This command displays the contents of a text file on the screen, including the extension TXT, BAT, ...

4.2 PRINT: external

This command to print an ASCII (text) file. If the port is not specified, the command ask it (see communication ports). If the option is omitted in the following command, it takes the device before. >Print fichier1 LPT1 and >print fichier1 PRN give the same result.

Wildcards (? and *) are permitted, but may cause problems with the printing of the executable .com or .exe files.

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