How To Create Bootable

How To Create Bootable
CDs
• Bootable CDs are an invaluable aid when dealing with large roll-outs and test rigs, and mprovements in CD writing software have made the process of creating them far simpler……By Matt Jones
• The most common applications for bootable CDs when undertaking large roll-outs and when using testrigs,where it is often useful to combine operating systemswith boot and diagnostic diskettes to automate the process of setting up machines.
• Repeatedly test from clean installations save lots of time.
• Most modern SCSI adapters have a BIOS that allows it, and most motherboards of the last two years support booting from IDE Cddrives.

Technical Details

• When a bootable CD is created, a“boot record” is put at the very begin-
ning of the CD, with a bootable floppy or hard disk.
• This record specifies whether the CD is to emulate a floppy or hard disk drive,and contains a pointer to the location of the actual boot image file.
• There’s no restriction on the location of the boot catalog.
• The catalog contains a list of entries describing all the “boot images” present on the CD.

There’s no restriction on where the boot images can be on theCD.There can be any number of them, of three different types:

1. “Bootable emulation” causes theimage to be mapped to drive A or
C, as a conventional bootable storage device.
2. “Non-bootable emulation” maps the image as a conventional storage device, and allocates the last drive letter to it.
3. “No emulation” is a special mode which loads the image intomemory and executes it – extremely useful when developing copy protection or “smart” CDs designed for a variety of disparate systems.

• To boot as drive A,the boot image must be made in the same format as a 1.2MB, 1.4MB or 2.88 MB floppy disk.
• If the system has a second floppy disk drive, it will not be accessible.

Creating The Image

• Most current CDR publishing packages are capable of reading a floppy disk and creating a boot image from it.
• With the appropriate menu choices made, they will automatically “inject”it into the Cdimage.
• The basic process formaking a bootable CD from a floppy disk is as follows:
1. It is wise to use a generic CD driver if you plan on using it in a few different systems.
2. Make sure that any path names in the config.sys andautoexec.bat files do not specify drive letters.
3. Set the read-only flag on all files and writeprotect the disk if possible. If your systemtries towrite to the CD on boot-up, it will crash.
4. Test this disk thoroughly in what ever PC environments you wish to use it.
• to create a larger, hard disk type image, choose and size source image hard disk carefully.
• Norton’s DiskEdit or PowerQuest’sDrive-Image to read the drive and create an image of it in a single file.
• Simply select the appropriate file and it will automatically create the correct boot records.
Tips

• A rewriteable CDR drive is an extremely useful tool when experimenting with bootable CDs.
• planning onmaking a variety of bootable CDs, or just experimenting, CDRW has the obvious advantage of media cost.
• When making hard disk image CDs, an old hard disk drive around 650MB in sizemakes a useful addition to your mastering system. it’s much easier to have a whole disk to use for your layout if you are doing this type of work.
• UnderWindows NT, youwill need to have administrative rights if you are creating hard disk images
• It is possible that you will encounter older CDs that start to boot, fail immediately and hang your system.
CDR Software
• Utility programs such as BOOTISO and DISKIMG were used to read bootable disks and write images to disk files.
• Notable software packages are Easy CD Creator, Win-OnCD, CDRWIN, HyCD and Nero.
• Many of these programs can be evaluated before purchase.

 

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