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How to install FAT-32 without reformatting

technofile  by al fasoldt

Columns and commentaries in a life-long dance with technology

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How to install FAT-32 without reformatting

July 6, 1997

By Al Fasoldt

Copyright © 1997, Al Fasoldt

Every disk has a file allocation table, or FAT, that stores vital information on how files and folders are organized on the disk. Most PCs have a standard file allocation table on each hard drive. This is called FAT-16 because it uses 16 binary digits (bits) to encode all its information.

FAT-16 file allocation tables cannot handle large drives well. On a 2-gigabyte drive that has a single partition, files are stored in large blocks of 32 kilobytes each. No matter how small a file is, it must take up 32K on that drive. This is not a big problem when storing large files, because the slack space (wasted disk space) is a small percentage of the file size. But the waste is almost incomprehensible if the disk holds a lot of small files such as shortcuts and icons; these files are usually quite small (a few hundred bytes, perhaps), yet each takes up take up 32K in storage. FAT-16 thereby wastes 32,468 bytes to store a single 300-byte shortcut. (32K is not 32,000 but 32,768.) A large file system with 1,000 files of less than 1,000 bytes—not an uncommon situation, I'm sure—would waste as much as 30 megabytes just in that category alone.

Another problem: FAT-16 partitions cannot be larger than 2 (or 2.1) gigabytes. Disks larger than this size must be partitioned into smaller logical drive units. This is not much of a limitation for most of us, but it can cause problems in the handling of very large databases (in which single files could exceed 2 gigabytes) and in drive arrays where all available drive designators, such as C:, D: and so on, are used up.

FAT-32 solves both problems. It uses 32-bit math to store information, and can therefore keep track of far more clusters. (The largest single partition under FAT-32 is 2 terabytes—2,000 gigabytes.) On "normal" large drives—a definition that will undoubtedly keep shifting upward—FAT-32 uses cluster sizes of 4K instead of FAT-16's 32K. FAT-32 maintains this 4K-cluster size for partitions up to 8 gigabytes.

Windows 95B, also called OSR2, is the first operating system to support FAT-32. Most new PCs come with Win95B, but FAT-32 may not be turned on. If you have a recently manufactured PC, check to see whether you have Win95B by right clicking on My Computer and choosing Properties. Look for the version number of Windows under the word "System." Win95B's version number is 4.00.950 B.

To see if your Win95B PC's C: drive already has FAT-32 enabled, open My Computer and right click on the C: icon. Choose Properties, and then look for the word "Type" under the disk label. Drives formatted for FAT-32 will have "Local Disk (FAT-32)" under the entry for the label. If you don't see "Local Disk (FAT-32" you can enable it following the instructions below.

The point of this article is to show you how to enable FAT-32 without reformatting your drive. However, if you do want to reformat the drive, you cannot do it using FORMAT alone. ("Format" is a program on your PC that organizes its sectors and tracks.) You must run FDISK, another program that comes with Windows, and choose FAT-32 when FDISK asks you. You'll also have to reboot after replying "Y" to the question of whether to use FAT-32. (This is not clear from the way FDISK works. Make sure you reboot.) After rebooting, run FDISK again and make one big partition.

Because FDISK is one of the best examples of a bad Microsoft program I have ever come across, I am recommending the following approach. It's much easier and almost totally foolproof. The drawback: You have to spend a little money, about $60.

That money buys you insurance of a sort, so start adding up what's worth more here. Does your labor come so cheaply that you can afford a lost weekend? Imagine the time taken up with backing up every file, reformatting your drive, reinstalling Windows from scratch, then using your backup program (you do have one, right?) to copy all the backed-up files back onto your hard drive, and then … heck, I don't even want to finish the sentence. The alternative is Partition Magic.

Partition Magic is one of those few products in American life that isn't overhyped. Partition Magic can change the size of partitions without endangering the data on them. DOS and Windows cannot do this; you lose everything on a drive when you change the size of a partition under the standard DOS and Windows utilities.

Partition Magic can also change the size of disk clusters the same, safe way, without endangering the data on them. I hope you are either a newbie or very impressed; if you're an old-timer and think this is just so much Mandarin tea, it's time you came out from under your rock. If you're a newcomer who's never had to deal with FDISK and FORMAT and never had to fall asleep with tears of anger and rage in your eyes because you just spent 18 hours battling the way PCs handle drives … well, you get the point, right?

Partition Magic is sold in stores and by mail order. You may have heard enthusiastic reports on Partition Magic; if so, just go out and buy it, or go to your favorite Web-based software store and order it. If you want to learn more about Partition Magic before you decide to buy, go to the PM Web site at and read what Partition Magic is all about.

After you install Partition Magic, just run it and tell it to change the cluster size of your disk. It will change your 16K or 32K clusters to 4K clusters. If you have a very large drive that has been partitioned into smaller units because of the 2-gigabyte limitation in the older Windows 95, you can also do all your repartitioning from within Partition Magic. Read the manual and follow the instructions. (Please note: I refuse to give you detailed instructions here on using Partition Magic. Changing the way your hard drive holds data can be risky no matter how you do it, so I want to be very sure you read the manual and look at the help files that come with Partition Magic.)

What will you gain by using Partition Magic to switch your drive (or drives—you may have two or more—over to FAT-32? You get the rest of the weekend to enjoy your PC, for one thing. You also get a chance to stand back from the allure of Windows and see just how bad Microsoft can be; the comparison between a really stunning program such as Partition Magic and the dreck that Microsoft sticks into Windows is an education in miniature. (To be sure, some of the utilities built into Windows are truly outstanding—ScanDisk, for example, which is beyond reproach in the way it can track down and cure disk and file problems, and DriveSpace 3, which is about as safe as any kind of massive compression can be, along with some others, all of which were licensed by Microsoft from other companies for inclusion in Windows! If I had to name two native Microsoft utilities in Windows that are worth admiring, I'd have to choose the Find utility and the system-management utility that shows up as the Device Manager.)

Be sure to make a note when you run Partition Magic of what it tells you about wasted space on your drive(s). FAT-16 is so wasteful on large drives that most users cannot believe the numbers. I know of more than one PC in which FAT-16 caused 40 percent waste on a large drive that held a great deal of small files. Finding out that your 2-gigabyte drive has 800 useless megabytes is not good news, but the changeover to FAT-32 will cure that kind of depression quickly.

If you run into problems or just want to know more about W95B, look at the OSR2 faq at

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