The starting of DOS is the process intervening with the starting of the computer before DOS is not available for the user.

Several files intervene in a preestablished chronology. At the conclusion of this launching phase, the core, msdos.sys and the interpreter of command.com order are charged in memory and available.

Two files IO.SYS and MSDOS.SYS are located at a particular site, in measurement or with their loading, the filing system is inaccessible.

Io.sys, the charger

See also: IO.SYS

IO.SYS is a file essential with the Démarrage of DOS.

It contains the peripheral interfacing owing to lack of DOS, as well as the routines of access to BIOS (by the interruption S 10:00 and 13:00).

In the cycle of starting of a compatible computer PC, with the Starting of a computer, the first sector of the disc of démmarage (the Master Boot Record) is carried out. if this one is a MBR DOS, it is able to charge in memory and to carry out the first 3 sectors of program IO.SYS.

Then the IO.SYS carries out the following actions:

1. takes care completely in memory
2. Initialize each data-processing Pilote in his turn (Console screen, Disque, Port series, in particular). This point, the peripherals by defect are available.
3. Load the program MSDOS.SYS and carries out its routine of initialization. This point, an access to the filing system is available.
4. Treats the file of configuration Config.sys.
5. Charge the interpreter of order by defect Command.com (or another like 4DOS if specified by the order “shell=” of the Config.sys file).

Msdos.sys, the core

See also: MSDOS.SYS

MSDOS.SYS is a file carried out with the starting of the operating systems MS-DOS and Windows 9x.

It is carried out immediately after IO.SYS and contains the center of the operating system MS/DOS (Noyau DOS).

On the Windows systems, this file MSDOS.SYS is simply a ASCII file which contains parameters of configuration directives.

By defect, the file is located in the root directory of the partition bootable (usually indicated by C:\ in the environments DOS and Windows) and has the Attribut S following files: Hidden, System, and reading alone.

IBM-DOS and PC-DOS use the equivalent file which is called IBMDOS.COM.

Config.sys, system requirements by the user-administrator

See also: Config.sys

Config.sys is a Textual file intervening in the starting of [[Operating system]] [[DOS]] and compatible the.

In the starting of a Operating system MS-DOS, this file intervenes after MSDOS.SYS and Io.sys and before Autoexec.bat.

This Textual file contains the orders of launching of hardware devices, and/or the orders of parameter setting of the MS-DOS system. For example the number of Buffer S used for the accesses discs, or the maximum number of files opened simultaneously (FILES).

Orders: One finds only some orders in the CONFIG.SYS. It is:

1. Orders of loading of programs
2. Orders of configuration of core DOS
3. Orders of Various menus

Example:

DEVICEHIGH= C:\DOS\ ANSI.SYS

SHELL= C:\DOS\COMMAND.COM /E: 1024 /P

to see too

• Process of starting of Windows NT