Disk partitioning with FDISK

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This is going to be a fun one to explain.  For some of you this will be too basic, and for others way too complex.  I'll attempt to find the middle ground.  I won't go into all the different partitioning strategies (like I know them all *g*), but I will try to cover the basics.

Who me?

Most new 'puters come with one partition, your "C" drive.   So you would say that your hard drive has one primary partition.  A hard drive can have a total of four primary partitions.  If you have more than one hard drive in your 'puter you *could* have more than four primary partitions. Since to some four partitions is too restrictive I'll throw a couple of other confusing terms at you:

A typical setup for a 'puter with one hard drive is to have one primary partition, one extended partition, and one to four logical drives (partitions) inside the extended partition.  There are whole books devoted to explaining the pro's and con's of different partitioning schemes.  The short version is if you haven't thought about disk partitioning schemes don't worry about it.  One primary partition (your "C" drive) is perfectly fine for most people.  If any of you wish to discuss partitioning schemes we'll have to set up a phone call.  In my mind it's too involved to discuss via email.

One other point I need to cover, drive letter rules.  Drive letters "A" and "B" are reserved for floppy drives.  All other letters are available (NOTE: I've heard that some networking setups require/reserve "X" as well. I'm not sure of this and have never seen this in practice).

Here's how it works, primary partitions are assigned drive letters first, then logical drives (partitions) get drive letters next, and finally removable media devices (CD-ROM's, zip drives etc...) get drive letters last.  This is why I strongly suggest making all removable media devices drive letters at the end of the alphabet.  An example, my CD-ROM is drive "X", my CD-ROM burner is drive "Y", and my zip drive is drive "Z".  This way no matter how you change your partitioning scheme your removable media drives can have consistent drive letter assignments (less confusion *g*).

Destructive VS. Non-destructive partitioning

Using FDISK (which comes with all versions of DOS and Win9x) is a destructive way to manage your partition(s). This means that if you create or destroy (you can't resize partitions with FDISK) you WILL DESTROY ALL DATA IN THE PARTITION(S)!!  So think about what you're about to do and don't get into a hurry.  I personally use Partition Magic by Powerquest .  This is a non-destructive way to create, resize, and add partitions. It's also very user friendly!  More on this program later on another page.

FDISK stands for

Before we get into how to use FDISK we need to talk about FAT16 and FAT32.   Fat16 has been used since sometime (I'm not sure how long) before MS-DOS 6.22.   FAT32 came out with Win95 OSR 2.0 and later.  Win95 OSR 2.0 and later (this includes Win98) can use either FAT16 or FAT32.  Besides some geek stuff (good reasons but most people don't want to know) there's a couple of pro's and con's as to which to use.  While some people argue that FAT32 slows down hard drive access, I see no reason not to use it.

The pro's of FAT32

The con's of FAT32  The PuterGeek.Com Button Link! Get It NOW!

An excerpt from the "General.txt" file included with Win95 OSR 2.0 and OSR 2.1

start quote...


The File Allocation Table (FAT) file system has been the primary disk format used by MS-DOS-based and Windows-based personal computers since 1981. FAT is a fast and broadly supported disk format, but until now, it has been unable to support single drives over 2 gigabytes (GB).  A gigabyte is equal to 1,024 megabytes, or approximately 1.07 billion bytes.

This product includes support for an enhanced version of the FAT file system, FAT32, that supports drives up to 2 terabytes (approximately 2,000 GB). It also allocates space on the drive in smaller units (called clusters) than earlier versions of FAT, resulting in more efficient use of space on the drive.

This section addresses some of the known issues with FAT32, and answers some of the questions you might have.

FAT32 is designed to be fully compatible with existing computers and programs designed to run on earlier versions of MS-DOS and Windows.  However, many existing disk utilities (programs that perform low-level
maintenance tasks on disks, such as disk compression or repair tools and defragmenters) will need to be updated in order to work with FAT32 drives. The disk tools contained with Windows, including ScanDisk, Backup, and Disk Defragmenter, fully support FAT32 drives. FAT32 drives cannot be compressed by using DriveSpace, however.

In addition, operating systems other than this version of Windows are unable to access information stored on FAT32 drives. This includes the original version of Windows 95, Windows NT 4.0 and earlier, and previous
versions of MS-DOS and Windows. However, this version of Windows does support accessing FAT32 drives in MS-DOS mode. In addition, FAT32 drives can be shared over a network and accessed by remote computers in the
same way as older-style FAT drives, even if the remote computers don't support FAT32.

Known Problems

Running Interlink on a FAT32 drive
If you are running Interlink as a server on a FAT32 drive, all connections and inquiries (such as DIR) result in the following error message: "File allocations table bad, Drive X." Also, the Interlink "manager" shows the incorrect total drive size.

This problem does not occur on FAT16 drives. To see your FAT32 server, start your computer in protect mode with Interlink running.

Incorrect free disk space reported by programs
Programs not developed specifically for this version of Windows may be unable to report free space accurately on large hard disks that use FAT32. Older programs are unable to report more than 2 GB of free or total disk space, and many will report incorrect amounts of free, total, or used space on large hard drives. Windows 95
version 4.00.950 B provides new MS-DOS and Win32 APIs that programs can use to determine free or total disk space over 2 GB.

Save to File (Hibernate) feature
may be incompatible with FAT32
On computers containing a BIOS made by Phoenix Technologies, you might not be able to use the Save to File feature if your primary (boot) drive is formatted using FAT32. If your PhDISK utility is earlier than version 5.0, you must obtain an updated version of the utility and an updated ROM BIOS from your computer manufacturer in
order to use a Save to Disk file.

With older versions of the ROM BIOS, your computer may be unable to start if it tries to read a Save to Disk file from a FAT32 drive. If this occurs, you must disable the Save to File feature in your ROM BIOS.  This does not affect computers using a disk partition to store the Save
to Disk data.

Ontrack Systems Disk Manager
If you use the Ontrack Systems Disk Manager program on a computer with FAT32 drives, there might be a long pause when you start your computer and/or the drive will be set to run in compatibility mode. If you use version 7.0x, you can avoid this pause by using the /L=0 option with Disk Manager. To do this, carry out the following steps:

1. Start your computer normally, and then run Disk Manager.

2. Click the Maintenance menu, and then click Update Dynamic Drive Overlay.

3. Add /L=0 to any other options that are already present.

4. Save the settings, and then restart your computer.

If you are running an earlier version of Disk Manager and you want to use FAT32, you should update to version 7.04 or later and use the /L=0 switch.

V Communications System Commander
Versions 2.28 and earlier of V Communications System Commander are incompatible with FAT32. If your primary (boot) hard disk uses FAT32 exclusively, you must obtain version 3 or later of System Commander.

Iomega Jaz tools may be incompatible with FAT32
If you format an Iomega Jaz disk using FAT32, you may need to obtain updated versions of the Jaz tools. Older versions of the tools do not support FAT32 Jaz disks properly. As a result, the eject, write-protection, and password-protection options will be disabled. Updated
versions of these tools that are compatible with FAT32 are available from Iomega, and from the Microsoft Windows Driver Library contained on the Windows CD-ROM disk and available for download from various on-line services.

SyQuest Technology, Inc. device drivers
Older versions of the Squatdvr.sys and Sqdriver.sys device drivers are incompatible with this version of Windows and will hang when your computer starts if your primary (boot) disk uses FAT32. You must remove the associated DEVICE= line from your Config.sys file in order to start your computer from a FAT32 drive. Updated versions of these drivers that are compatible with FAT32 are available from SyQuest, and from the Microsoft Windows Driver Library contained on the Windows CD-ROM disk and available for download from various on-line services.

Questions and Answers

How do I tell if a drive is a FAT32 drive?
In My Computer, right-click the icon that represents your hard disk, and then click Properties. The kind of drive you are using is indicated after the word Type at the top of the screen.

How do I enable FAT32?
If you obtained this version of Windows with a new computer system, it may already be using the FAT32 disk format. If not, or if you add a new hard disk to your computer and you want to use the FAT32 file system, you enable it by running the FDISK program. FDISK is a program used to create or delete one or more partitions on a hard disk. A partition is a section of a hard disk that appears to be a single disk drive. Most hard disks must be partitioned with FDISK before they can be used with Windows. If your computer has a disk drive larger than 512 megabytes (MB), when you run FDISK it will prompt you whether to enable large disk support. If you answer yes, then any partition you create that is over 512 MB will use the FAT32 file system. If you answer no, then you will be unable to create disk partitions larger than 2GB. After creating a partition with FDISK, you must restart your computer and then format the drive before you can store data on it.

IMPORTANT NOTE: FDISK is an extremely powerful program. If you delete a disk partition by using FDISK, all the data in that partition will be permanently destroyed. If you are unfamiliar with FDISK, you may want to consult a qualified computer technician before using it.

Is FAT32 faster than earlier versions of FAT?
In general, no. In most cases, your computer will perform about the same if your hard disk is formatted by using FAT32 as it did previously. In some cases, however, performance may be worse than with the original version of FAT.

Note that FAT32 drives may be significantly slower when your computer is running is MS-DOS mode or when you are running Windows in Safe Mode. If you use MS-DOS mode with FAT32 drives, you may find that performance is improved significantly by loading the Smart Drive disk-caching program.

What size clusters are used on FAT32 drives?
The following cluster sizes are typically used on FAT32 drives:

Drive size Cluster size
----------- ------------
<260 MB 512 bytes
260 MB - 8 GB 4 kilobytes (KB)
6 MB - 16 GB 8 KB
16 MB - 32 GB 16 KB
>32 GB 32 KB

Can I use disk compression on FAT32 drives?
No. DriveSpace 3 does not support compressing FAT32 drives.

...end quote  The PuterGeek.Com Button Link! Get It NOW!

Click on the image to see full size.

fdisk1.gif (12818 bytes)

fdisk2.gif (8591 bytes)

fdisk3.gif (9205 bytes)

And now for the short version.  After you type FDISK you'll see the first screen (upper left) NOTE: if you're using Win95 OSR 1.5 or older you won't see this screen.  If you want FAT32 say yes then hit enter. At the second screen (upper right) you'll either start deleting partitions or creating partitions. It tends to get rather confusing but if you take it slow you'll be alright.  Remember if you delete a partition you WILL LOSE ALL DATA IN THAT PARTITION!  When you think you're done, don't forget to make a primary partition active.  See the third screen shot (lower left).  Otherwise when you reboot your 'puter it won't see any hard drives!

It seems the more ground I cover about FDISK and partitioning the more that needs to be said.  I realize that there is plenty of ground I've failed to cover but that is what good books are for.  I'll leave this with a couple of comments about FDISK.  While you could have four primary partitions, FDISK will only allow you to create one.  There are other issues with FDISK as well, such as the fact that there are hidden switches that allow you to change the way FDISK works (I don't know them all).   And it's almost impossible to create both FAT32 and FAT16 partitions on the same hard drive. The current version of FDISK will only make partitions greater than 512 meg FAT32 (I've heard that there's a switch to over-ride that.  If anyone knows it please let me know).  All these issues and more are addressed by Partition Magic by Powerquest.

New info found by Andy

Here are (hopefully) all the switches for FDISK.

Last but not least I'll give you a blow-by-blow example.  This assumes that you have one 4.3 gig hard drive, and that you want one primary partition (your "C" drive) and three logical partitions for the following... data, games, and the windows swap file. (NOTE: this is just one common setup)  REMEMBER, IF YOU MESS WITH AN EXISTING PARTITION ALL DATA WILL BE LOST!!

At this point if you were careful you're done.  Look at this screen carefully and make sure it's how you want everything.  If it's not, start over.   Remember with FDISK you can't resize a partition later without destroying all data!

I hope this helps.  Let me know if you need/want more info...

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Last Revised: 10/21/2000