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System disk

A system disk, also sometimes called a boot disk, is a disk that will allow you to start a computer when the operating system no longer responds, as the result of a virus for example. This disk contains special information that makes it possible to bootstrap the system without touching the hard drive. There is no single type of startup disk: each operating system has its own startup disk.

It is absolutely necessary to have a system disk, as it is the only way to restart a computer in the event of defects in the MBR if your computer doesn't let you boot from a CD-ROM!

How to create a startup disk?

Under MS-DOS

Insert an unprotected blank floppy disk into drive a:

Then all you need to do is type the command:

format a: /s

Under Windows 95/98/Me

Insert an unprotected blank floppy disk into drive a:

Then go to:
Start / Parameters / Control Panel / Add/Delete programs / Startup disk
Then click create a startup disk

Under Windows 2000

To create an emergency repair disk under Windows 2000 click on Start > Programs > Accessories > System tools > Backup. Under the General tab, click on the Create an emergency repair disk button. When prompted, insert a blank, formatted 1.44 MB floppy disk into the disk drive, and then click on OK. Once complete, remove the disk, write "Emergency repair disk" on the label and keep it in a safe place.

To restore parameters from the repair disk, you need to have your Windows 2000 CD-ROM, the Windows 2000 installation disks and the emergency repair disk. During the restore process, you can press F1 to get additional information on the options.

Under Windows XP

Insert an unprotected blank floppy disk into drive a:

Then go to:
My computer
Right click on Format, and then choose the option Create an MS-DOS startup disk.

It is essential to set the write-protect tab on the floppy disk just after you create it to ensure that it will not be contaminated by a virus when you need it to restart your computer.

What do you do with the floppy disk?

The BOOT disk can only be used to reboot your computer in MS-DOS after a crash. To be "valid", the BOOT disk must:

• Not be infected by a virus
• Have anti-virus software (that works under DOS)
• Be write-protected so that no virus can hide there after you run the anti-virus software
• You will also need the installation disks of your operating system (if it is a CD-ROM make sure that the CD-ROM drivers are loaded when you boot from the floppy disk!)

Startup sequence

PC-type computers let you configure the order in which the drives are searched for an operating system when the computer starts up. This order, called the boot sequence, can be configured in the computer's BIOS setup. This allows you, for example, to configure the computer so that it looks for the operating system first on the IDE hard drive, then on the CD-ROM drive and finally on a SCSI drive.

To be able to start from the system disk, you must make sure that no drive located earlier than the floppy disk drive in the boot sequence contains an operating system. By default, most BIOSes start the boot sequence with the floppy drive.

How to transfer the system files from the floppy disk to the hard drive?

After the system has been started from a boot disk and the hard drives have been carefully verified using anti-virus software, you can transfer the system files from the boot disk so that you will be able to boot from the hard drive. To do this, type the following command:

sys a: c:

The operating system used to make the system disk must be the same as the system installed on the hard drive...

If you forget to use the "/s" switch when formatting a hard drive using the format command under DOS, the computer will not be able to start the operating system. The system will then display the following message: Non system disk / Disk error In this case, you should boot from your system disk and then execute the command sys a: c:.