Upgrading and Repairing PCs

Booting from a Floppy Disk with CD/DVD Drive Support

You might need to boot from a floppy drive on a modern PC for many reasons. One reason is to install an operating system on a newly built system or one with a new or unformatted hard drive. In that case, because the system cannot boot from the hard drive, it must boot from a CD or floppy instead.

For a CD or DVD drive to function in a floppy (or CD) boot environment, several drivers might be necessary:

• An ATAPI host adapter driver (not needed for SCSI drives). This driver is included with your motherboard, or you can use the generic ATAPI drivers found on Windows 98 and later startup disks.

• SCSI adapter drivers (not needed for ATAPI drives). Most SCSI cards include these drivers, or you can use the generic versions included on Windows 98 and later startup disks.

• MSCDEX. Microsoft CD Extensions, which is included with DOS 6.0 and later. It is also built into Windows 95 and later as the CDFS VxD.

If you need to start a PC from a bootable floppy, the floppy must contain not only a bootable OS, but also the previously mentioned drivers; otherwise, the CD-ROM will be inaccessible.

You will need one of the first two drivers (ATAPI or SCSI) as well as the third one for the drive to work in a floppy (or CD) boot environment. Generic ATAPI and SCSI drivers can be found on the Windows 98 and newer startup disks. Rather than create custom CONFIG.SYS and AUTOEXEC.BAT files, the best advice I can give is to merely boot from a Windows 98 or Me startup floppy because each time you boot from these, the proper drivers load and autodetect the CD/DVD drives, after which the drives are accessible. You can generate a Windows 98/Me startup disk on any system running Windows 98 or Me. If you don't have access to a Windows 98 or Me system, you can download an equivelant bootable floppy from www.bootdisk.com.

After you boot from a Win98/Me floppy, you see a menu that asks whether you want to boot with or without CD-ROM (and DVD) support. If you select yes, after the floppy finishes loading, you should be able to read any discs in the CD or DVD drives.

One possible, and useful, task with this capability is to install any version of Windows in a situation where the installation CD is not bootable (such as with most versions of Windows 9x/Me) or where the system is older than 1998 and cannot boot from a CD. In such a case, all you need to install any version of Windows is the Windows CD and your bootable Windows 98/Me startup floppy. In addition, the fact that the startup floppy is from Windows 98 or Me does not matter—you can install any Windows OS using that floppy.

For example, to install Windows 9x/Me onto a system, you could do the following:

To install Windows NT, 2000, or XP onto a system, do the following:

Another useful function you can perform with a Windows 98/Me startup floppy is to format a hard drive larger than 32GiB with FAT32 for use with Windows 2000 or XP. The Format program in Windows 2000 and XP is intentionally restricted by Microsoft from formatting volumes larger than 32GiB even though Windows 2000 and XP support FAT32 volumes up to 2TiB in size. In most cases it is recommended to use NTFS on Windows 2000 or XP systems, but if you are creating a dual-boot environment in which you want to run other operating systems that do not support NTFS, FAT32 is the best choice. The restriction on the Windows 2000/XP format command is a nuisance in such a situation, but the only way around it is to use the format from 98/Me.

Although I've often used a Windows 98/Me startup floppy to install Windows XP, Microsoft does have official XP startup floppies available for downloading from its Web site. The file is an executable file that creates the startup floppies. To locate this file, visit the Microsoft Knowledgebase at support.microsoft.com and search for article number 310994.

Using a CD-ROM or DVD-ROM drive that conforms to the ATAPI specification under Windows does not require you to do anything. All the driver support for these drives is built into Windows 9x and later versions, including the ATAPI driver and the CDFS VxD driver.

If you are running a SCSI CD-ROM drive under Windows, you may still need the ASPI driver that goes with your drive. The ASPI driver for your drive usually comes from the drive manufacturer and is included with the drive in most cases. However, by arrangement with hardware manufacturers, Windows typically includes the ASPI driver for most SCSI host adapters and also automatically runs the CDFS VxD virtual device driver. In some rare cases, you might have to install an updated driver that you have obtained from the manufacturer.

When you install a PnP SCSI host adapter in a Windows system, simply booting the computer should cause the operating system to detect, identify, and install drivers for the new device. When the driver for the host adapter is active, the system should detect the SCSI devices connected to the adapter and again load the appropriate drivers automatically.

For DOS users, merely use the Windows 98 or Me startup disk, which includes the necessary DOS SCSI and CD-ROM drivers that support most SCSI cards and CD/DVD drives on the market.

To learn more about the process of preparing to use a CD/DVD drive from a DOS prompt, see "DOS ATAPI CD-ROM Device Driver" in the Technical Reference portion of the DVD packaged with this book.

Bootable CDs and DVDs—El Torito

If your system BIOS is a version dated from 1998 or later, most likely it has "El Torito" support, which means it supports booting from a bootable CD or DVD. The El Torito name comes from the Phoenix/IBM Bootable CD-ROM Format Specification, which was actually named after the El Torito restaurant located near the Phoenix Software offices where the two engineers who developed the standard ate lunch. What El Torito means for the PC is the capability to boot from CDs or DVDs, which opens up several new possibilities, including creating bootable CD/DVD rescue discs, booting from newer OS discs when installing to new systems, creating bootable diagnostics and test CDs, and more.

To create a bootable CD, ideally you need a CD/DVD burning application that allows the creation of bootable discs. Additionally, in some cases you need a bootable floppy that contains the drivers to support your CD drive in DOS mode (sometimes called real-mode drivers). The best source for these drivers (if needed) is a Windows 98 or Me startup floppy, which can be generated by any Windows 98 or Me system. Windows 98/Me startup disks can be used because these have the DOS-level CD-ROM support already configured and installed. If you don't have access to such a system to generate the disk, you can download one from www.bootdisk.com.

Before creating the bootable CD/DVD, test your boot floppy (with CD-ROM drivers) by first booting to the floppy. Then, with a CD or DVD containing files in the CD/DVD drive, see whether you can change to the CD/DVD drive and read a directory of the files (try the DIR command). The CD/DVD usually is the next drive letter after your last hard drive letter. For example, if your last hard drive letter is C:, the CD/DVD will be D:.

If you can display a directory listing of the CD/DVD after booting from the floppy, your drivers are properly loaded.

To create a bootable CD or DVD, simply follow the directions included with your CD/DVD burning application. Programs such as CD/DVD Creater by Roxio and Nero Burning ROM by Ahead Software make the creation of bootable discs a relatively easy procedure.

Removable Drive Letter Assignments

One problem people have when installing new drives is confusion with drive letter assignments. This becomes especially true when adding a new drive moves the assignments of previous drives—something most people don't expect. Some simple rules govern drive letter assignments in Windows and DOS, which are discussed here.

All versions of Windows (as well as MS-DOS) treat floppy drives and drives such as Zip, SuperDisk, and flash memory devices the same way, but major differences exist in the management of hard drives, CD-ROM/optical drives, and removable-media hard drives with Windows 9x/Me on the one hand and Windows NT/2000/XP on the other hand.

With any version of MS-DOS or Windows, the system assigns the drive letter A to the first physical floppy drive. If a second physical floppy drive is present, it is assigned drive letter B. If no second floppy drive exists, the system automatically reserves B: as a logical drive representation of the same physical drive A:. This allows files to be copied from one disk to another by specifying COPY file.ext A: B:.

MS-DOS and Windows 9x/Me Disk Management

The basic rule with these operating systems is that devices supported by ROM BIOS–based drivers come first and those assigned by disk-loaded drivers come second. Because floppy drives and hard drives are usually ROM BIOS supported, these come first, before any other removable drives. After assigning A: and B: to floppy drives, the system then checks for installed hard drives and begins by assigning C: to the master partition on the first drive. If you have only one hard disk, any extended partitions on that drive are read and any volumes in them are assigned consecutive letters after C:. For example, if you have a hard disk with a primary partition as C: and an extended partition divided into two logical volumes, they will be assigned D: and E:.

After the hard drive partitions and logical volumes are assigned, the system begins assigning letters to devices that are driver controlled, such as CD-ROM drives, PCMCIA-attached devices, parallel port devices, SCSI devices, and so on. Here is how it works with only one hard drive split into three volumes and a CD-ROM drive:

One drive primary partition	C:
One drive extended partition 1st volume	D:
One drive extended partition 2nd volume	E:
Optical drive (CD, DVD, MO)	F:

When a removable drive is added to the system proposed in the previous scenario, it is assigned either F: or G:, depending on the driver and when it is loaded. If the CD-ROM driver is loaded first, the removable drive is G:. If the removable drive driver is loaded first, it becomes F: and the CD-ROM drive is bumped to G:. In DOS, you control the driver load order by rearranging the DEVICE= statements in the CONFIG.SYS file. This doesn't work in Windows because Windows 9x, Me, NT, and 2000 use 32-bit drivers, which aren't loaded via CONFIG.SYS. You can exert control over the drive letters in Windows by manually assigning drive letters to the CD-ROM or removable drives. You do this as follows with Windows 9x and Windows Me:

Using these steps, you can interchange the removable drive with the CD-ROM drive, but you can't set either type to a drive letter below any of your existing floppy or hard drives.

So far, this seems just as everybody would expect, but from here forward is where it can get strange. The rule is that the system always assigns a drive letter to all primary partitions first and all logical volumes in extended partitions second. Therefore, if you have a second hard disk, it also can have primary and extended partitions, the extended partition can have two logical volumes, and the primary partition on the second drive could become D:, with the extended partition logical volumes becoming G: and H:.

Here is how it works with two hard drives, each split into three volumes, and an optical drive:

First drive primary partition	C:
Second drive primary partition	D:
First drive extended partition 1st volume	E:
First drive extended partition 2nd volume	F:
Second drive extended partition 1st volume	G:
Second drive extended partition 2nd volume	H:
Optical drive (CD, DVD, MO)	I:

In this example, if a removable drive were added, it would become either I: or J:. Using the same procedure outlined previously, you could swap I: or J: or assign them higher (but not lower) letters as well. Some factory-installed removable drives that use the ATA interface (such as some versions of the Zip 100 ATA) act like a second hard disk, rather than an add-on removable drive.

The utility software provided with the Iomega Zip drives also can be used to assign the drive to any available drive letter.

To avoid scrambling existing hard drive letters when you install additional drives, prepare additional drives with extended partitions only. Drive letters in the extended partition on the second drive will follow the drive letters in the first drive's extended partitions and so forth if you install a third or even more hard drives. Here's what the result would be when you have two hard drives, with the first drive split up as a primary disk partition with two drives in an extended partition, and the second drive having no primary partition, but three logical drives in its extended partition:

First drive primary partition	C:
First drive extended partition 1st volume	D:
First drive extended partition 2nd volume	E:
Second drive extended partition 1st volume	F:
Second drive extended partition 2nd volume	G:
Second drive extended partition 3rd volume	H:

Drive Remapping Utilities Although some utilities are available for remapping drive letters under Windows, I normally don't recommend them. This is because if you boot under DOS or via a floppy, these remappings are no longer in place and the standard BIOS mapping prevails. Because you often might boot to DOS to perform setup, diagnostics, configuration, or formatting/partitioning, confusion about which drive letters are what can lead to mistakes and lost data! If you reset your CD-ROM or other removable-media drive to a different drive letter in Windows, be sure to set the drive to the same letter when you run the computer in command-prompt or MS-DOS mode. This is typically done through command-line options you can add to the AUTOEXEC.BAT statement for the drive. See your drive's instruction manual for details.

Windows NT/2000/XP Disk Management

Disk management for NT-based versions of Windows, including Windows NT/2000/XP, offers many more options than in MS-DOS and Windows 9x/Me. The Disk Administrator tool is launched from the Drive properties Tools menu in Windows NT 4.0. The similar Disk Management tool is started from the Computer Management (Microsoft Management Console) utility in Windows 2000 and XP. Both Disk Administrator and Disk Management can be used to control drive letters. To change a drive letter with either tool, right-click the drive and select Change Drive Letter and Path.

Although the C: drive is assigned to the first hard drive by default in these versions of Windows, you can assign the drive letters you prefer to both CD-ROM/removable-media drives and to logical drives on a hard disk. If you install Windows 2000 or Windows XP as a dual-boot operating system to a different partition than the one used by Windows 9x/Me, the boot drive letter used by Windows 2000/XP is the next available drive letter. By default, when additional hard-disk-based logical drives are added to a system, existing CD-ROM or other removable-media drive letters are not disturbed. Therefore, programs that depend on CD-ROM or removable-media drive paths continue to work.

You also can change the default boot drive letter from C: to another drive letter, but this is not recommended because it prevents your system from booting until manual Registry changes are made to correct the problem.

Creating a Rescue CD

Several programs on the market today allow you to make a compressed image file of the contents of any drive. These programs, such as the Ghost program sold by Symantec or PowerQuest's Drive Image, enable you to lock in the condition of any drive as of a particular time.

This enables you to create an image file of your system when it's working and use the image-restore feature to reset your system when it fails.

The perfect place to store a compressed image file is on a CD-R. At a minimum, your rescue disk should contain the compressed image file (a 737MB, 80-minute CD-R/RW could contain the equivalent of a nearly 1.5GB drive's normal contents if the maximum compression option is used). It's also desirable to place a copy of the image-restore program on the CD. Mastering this type of rescue CD is done exactly the same as a conventional CD mastering process. To use the rescue CD, you must boot your system with drivers that allow the CD-ROM drive to work, run the restore program to read the data from the CD, and overwrite the drive's existing contents.

If you're looking for a single-CD solution to rescuing your system, one that won't require you to lug around a bootable floppy disk, you can burn a rescue CD that is bootable all by itself.

Making a Bootable CD/DVD for Emergencies

A little-known capability to PC users is that they can create their own versions of what is standard with more and more new computers: a bootable CD/DVD that can be used to start up a system and restore it to a previously saved state.

The minimum requirements for a bootable CD/DVD include

• A system supporting the El Torito standard in which the CD/DVD can be designated as a boot drive. Check your BIOS under Advanced Setup or similar options. Recent and current BIOS code supplied by AMI, Award Software, and Phoenix Technologies typically support El Torito, meaning the CD/DVD can be assigned as a bootable device.

• A CD/DVD burner and media.

• Recording software that allows creation of a bootable CD. Most modern CD recording software, such as NERO Burning ROM or Roxio CD/DVD Creator, support creating bootable CD/DVDs. If your current CD/DVD-recording software lacks this option, you must upgrade to something that does.

• A floppy disk containing your operating system boot files.

ATAPI Drives Are Bootable Most ATAPI drives connected to a motherboard ATA interface can be used as bootable devices if the BIOS permits it. If your CD-ROM is connected to a sound card, this procedure won't work. If your CD/DVD is connected to a SCSI interface, you'll need a SCSI interface with a BIOS chip that permits booting as well as a bootable disc. Check your BIOS Setup for a page on which boot devices are listed to see whether yours supports a CD/DVD drive as a bootable device.

Because the procedures can vary for different burning software, you should follow the directions that come with your software for the exact procedure for creating a bootable CD or DVD.