Microsoft KB Archive/243896

= How to Dual Boot Windows 98 and Windows NT 4.0 with FAT16 or NTFS Volumes =

Article ID: 243896

Article Last Modified on 1/25/2007

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APPLIES TO


 * Microsoft Windows 98 Standard Edition
 * Microsoft Windows NT Server 4.0 Standard Edition
 * Microsoft Windows NT Workstation 4.0 Developer Edition

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This article was previously published under Q243896



SUMMARY
This article describes how to dual boot between Windows NT 4.0 using an NTFS partition of any size, while allowing Windows 98 to reside on a large volume using FAT32.

For Windows 98 to coexist with Windows NT 4.0 on a large NTFS partition, a small FAT active partition must exist at the beginning of the drive. Currently, FAT16 using the 32-KB cluster size is the only common file system that both operating systems can address from Power On Self-Test (POST). Therefore, making a FAT drive C partition that is 2 GB in size or less, ensures the proper cluster size is used.

If the active partition is NTFS or large FAT16 using the 64-KB cluster size, Windows 98 does not boot because these file systems are not accessible to the boot code that Windows 98 uses. Likewise, if the active partition is FAT32, Windows NT does not boot.



MORE INFORMATION
You can use the following procedure to define the partitions you need using the Fdisk tool. After you install Windows NT, you should avoid formatting logical drives as NTFS within the extended partition. Although you can do this from Disk Administrator, it is not supported because Fdisk cannot recognize NTFS logical drives within an extended partition. You should note that if you make NTFS logical drives, any future deletion of a FAT logical drive under Fdisk results in the accidental deletion of the first NTFS logical drive instead. To prevent the accidental deletion of a NTFS logical drive, you should create all logical drives within Fdisk and delete them from Disk Administrator. You should then format the RAW logical drives from within the operating system that you want to have access to that logical drive.

To prevent cumbersome workarounds to recover boot sectors and to ensure the successful installation of Windows NT 4.0 to an NTFS partition while still being able to dual boot with Windows 98, use the following steps:  Install Windows NT 4.0 from the floppy disks or CD-ROM. In Windows NT Setup, create a primary drive C partition that is at least 300 MB in size. Select FAT as the file system and proceed with a minimal installation of Windows NT (this installation of Windows NT will not exist later).

NOTE: If you are installing Windows NT to an IDE drive that is larger than 7.8 GB, you need to install Windows NT 4.0 Service Pack 4 (SP4) or later after Setup is finished. This is because the updated Atapi.sys driver from SP4 enables Windows NT to view large IDE drives correctly. Restart the computer using the Windows 98 startup disk. Run Fdisk and click Yes when you receive a prompt about Large Disk Support. Create an extended partition that is as large as you want. Be sure to leave room at the end of the disk for the Windows NT boot partition that you will create later from the temporary installation of Windows NT on drive C.

NOTE: When you create the extended partition, you must subtract the amount of space you want for Windows NT from the total space available for the extended partition. If Windows NT will ultimately reside on an NTFS partition, you can make the primary partition as large as you want. If you want to install Windows NT on a FAT16 partition, the partition must not exceed 2,048 MB in size. Exceeding 2,048 MB for a Windows NT FAT volume forces the use of 64-KB clusters, which is unsupported when dual booting Windows NT with Windows 95 and Windows 98 (and causes Windows 95/98 Setup to be unsuccessful). For this reason, you should use NTFS when volumes greater than 2 GB are needed for Windows NT. Fdisk prompts you to create a logical drive. You should make the logical drive for the Windows 98 installation the full length of the extended partition. If you intend on making more than one logical drive, the first drive should be your Windows 98 installation partition. After your logical drive is created, quit Fdisk. Restart the computer using the Windows 98 Startup disk and select CD-ROM support.</li> Change to the CD-ROM drive where the Windows 98 CD-ROM is located and go to the Win98 folder. Type format (where   is the logical drive on which you want to install Windows 98.</li> When format finishes, reboot into Windows NT 4.0 and run Disk Administrator.</li> At the end of the disk behind the extended partition, right-click in the free space and click Create to make a primary partition. This partition is the permanent location of Windows NT 4.0. Click Commit the Changes Now and format the partition as appropriate.</li> Restart the computer using the Windows 98 Startup disk and select CD-ROM support.</li> Change to the CD-ROM drive where the Windows 98 CD-ROM is located and go to the Win98 folder. Type format c: /s.

NOTE: This action formats over the current installation of Windows NT 4.0, and creates the Bootsect.dos and Boot.ini entries for Windows when Windows NT 4.0 is installed to the new primary partition in the next step.</li> Run Windows NT 4.0 Setup from the floppy disks or CD-ROM.

NOTE: If you are installing Windows NT 4.0 to a large IDE drive and the partition on which you are installing Windows NT resides on or past the first 7.8 GB of the hard disk, you should obtain the Atapi.exe file and follow the steps outlined in the following Microsoft Knowledge Base article before you install Windows NT:

197667 Installing Windows NT on a Large IDE Hard Disk

You can download the Atapi.exe file from the following Microsoft Web site:

ftp://ftp.microsoft.com/bussys/winnt/winnt-unsup-ed/fixes/nt40/atapi/atapi.exe

</li> In the text-mode portion of Windows NT Setup you can see your partitions. Highlight the last partition and press ENTER to continue the installation. This is your production installation of Windows NT.</li> When you are prompted, click Leave Current File System Intact.

NOTE: If the boot partition on which you are installing Windows NT 4.0 is beyond the reach of INT13 BIOS calls, the controller driver is copied to the root of the C drive and named Ntbootdd.sys. This means the ARC path in the Boot.ini file uses SCSI syntax to address the drive. Using SCSI syntax to address the drive at POST can cause a 20-30 second delay after the Boot.ini (where the screen is black).</li> Finish installing Windows NT 4.0. Restart the computer using the Windows 98 Startup disk and select CD-ROM support.</li> Change to the CD-ROM drive where the Windows 98 CD-ROM is located. Go to the Win98 folder and type setup from the same location.</li> During Setup, do not install to the C:\Windows folder. Click Other and install to :\Windows (where   is the logical drive on which you want to install Windows 98).</li></ol>

After Windows 98 Setup is finished, both operating systems boot normally and the Boot.ini file is updated to show Windows 98 as a valid choice.

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