Hard Drive Profile
A Hard Drive Profile defines the "Logical" organization of the drive for use at the OS level. This is read first.

Bootstrap/Master Boot Record/Boot Sector
• Each Hard Drive contains a bootstrap at the beginning of the customer usable area. It's location is always at the beginning of the drive. The way it's location is represented and what it is called depends on the OS.
•In the case of DOS/Windows, it is called the Master Boot Record or Boot Sector and can be found at the first sector of the disk (cylinder 0, side 0, sector 1). The partition table is located at offset 01BE, containing up to four 16-byte entries. The fourth byte of each partition table entry is used to mark the partition type.
•A bootstrap/MBR will contain a header, Boot Loader program, and Partition Table.
•Boot Sector Viruses, will replace the Boot Loader with their program to ensure they are loaded first. Frequently, they damage the bootstrap/MBR in some manor, requiring the bootstrap/MBR be recreated to remove the virus.

DOS/Windows 95A/95B(OSR2)/98/98SE/ME Partition Table

Partition  Type Fdisk Reports           Size      Fat type Starting in V ersion
   01               PRI Dos          00MB-15MB    12-Bit       MS-DOS 2.0
   04               PRI Dos          16MB-32MB    16-Bit       MS DOS 3.0
   05               EXT DOS          00MB-02GB     N/A         MS-DOS 3.3
   06               PRI DOS          32MB-02GB    16-bit       MS-DOS 4
   OE               PRI DOS          32MB-02GB    16-bit       Win95 
   OF               EXT DOS          00MB-02GB     N/A         Win95
   OB               PRI DOS         512MB-02TB    32-bit       OSR2
   OC               EXT DOS         512MB-02TB    32-bit       OSR2
 
Types 0E, 0F, and 0C require extended Int13 support.

File System types.
•Windows 95A/95B(OSR2)/98/98SE/ME Fat16
•Windows 95B(OSR2)/98/98SE/ME FAT32. The one downside of FAT32 is the larger cluster size. Each file will be assigned one cluster even if it is not fully utilized. So, if your file is 1K, but you cluster is 8K, then 7K is wasted. You can get around this issue by using the DOS Format command using the /z: hidden option and specify how many sectors to assign to a cluster. If you use format d: /z:4 then four 512 byte sectors will be arranged per cluster for a total cluster size of 2K.
•Overview of FAT, HPFS, and NTFS File Systems.

Drive Assignment
•MS-DOS/Windows assigns drive letters to the first two physical floppy disk drives and hard disk drives it finds at boot time in a fixed sequence, including multiple partitions and logical drives on the hard disks. You cannot change this sequence.
•The following occurs at startup:

•MS-DOS checks all installed disk devices, assigning the drive letter A to the first physical floppy disk drive that is found.
•If a second physical floppy disk drive is present, it is assigned drive letter B.
•MS-DOS then assigns the drive letter C to the primary MS-DOS partition on the first physical hard disk.
•If a second physical hard disk is found, and a primary partition exists on the second physical drive, the primary MS-DOS partition on the second physical hard drive is assigned the letter D.
•MS-DOS/Windows will continue to search for more physical hard disk drives at this point and if a third physical hard disk is found with a primary partition it will be assigned to the letter E.
•After all Drives have been searched for a Primary Partition, MS-DOS will return to the first physical hard disk drive and assigns drive letters to any additional logical drives (in extended MS-DOS partitions) on that drive in sequence.

Example 1

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Drive 1:
C: 20 MB primary MS-DOS partition
E: 20 MB logical drive 1 in extended MS-DOS partition

Drive 2:
D: 20 MB primary MS-DOS partition
F: 20 MB logical drive 1 in extended MS-DOS partition

Example 2

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Drive 1:
C: 20 MB primary MS-DOS partition
D: 20 MB logical drive 1 in extended MS-DOS partition

Drive 2:
E: 20 MB logical drive 1 in extended MS-DOS partition
F: 20 MB logical drive 2 in extended MS-DOS partition

Example 3

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Drive 1:
C: 10 MB primary MS-DOS partition
E: 10 MB logical drive 1 in extended MS-DOS partition
F: 10 MB logical drive 2 in extended MS-DOS partition
G: 10 MB logical drive 3 in extended MS-DOS partition

Drive 2:
D: 10 MB primary MS-DOS partition
H: 10 MB logical drive 1 in extended MS-DOS partition
I: 10 MB logical drive 2 in extended MS-DOS partition
J: 10 MB logical drive 3 in extended MS-DOS partition


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Requirements

1. Hard Drive.
2. Access to a MS-DOS Command prompt.
3. Access to the command fdisk (By default can be found in c:\windows\commands).
4. Preferably a boot floppy disk, with the usual assortment of commands, such as fdisk, format, and ....

Considerations
1. If this is the Primary Master Bootable hard Drive, you will need to create a Primary Partition for the Operating System.
2. If this is not the Primary Master Bootable Hard Drive, consider creating an Extended PartitIon with Logical Drives within it. This will allow all Drive Assignments to remain in order.
3. What type of file system do you want to use? You can use either the FAT16 or the FAT32 File Systems.
4. Consider if you want to maintain separate partitions for the Windows OS and your Data. There are several schools of thought and it's pretty much your preference.
• One Partition for everything, may be a little less maintenance. It has drawbacks when you have to upgrade or fix Windows, since your data will have to be saved to a different media first.
• Two Partitions, one for Windows and one for your data. May be a little confusing to some, since your data will reside in an extended partition on a logical drive as D:. It has a benefit by increasing your options if you have to upgrade or fix Windows, since your data resides in a different partition.

Partitioning
MS KB #255867 - Monster KB on partitioning for Win95->WinME
MS KB #313348 - Partitioning In Windows XP
Summary on DOS/Win95/Win98 Partitioning
Overview of FAT, HPFS, and NTFS File Systems

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by vkr edited by dbmaven
last modified: 2003-09-10 16:16:04