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Partitioning a Hard Drive, part 2

Copyright ©, Myles White, 2000

In last week's Computer Wares, I described why you may want to partition a large hard drive and, just to recap briefly for those who may have missed it, the reason is that if you don't, you could be wasting as much as 30 per cent of your drive's space.

There is a physical limit imposed on the number of small sections of the hard drive, called clusters and defined as the smallest portion of the drive into which data can be placed. The number of clusters on any given drive is determined by the size of a drive partition and the file allocation scheme used to keep track of where data is on the drive's surface.

Using the 16-bit file allocation table (FAT16) found in earlier versions of Windows (95 and earlier), the maximum number of clusters in a partition was 65,535. Under the 32-bit file allocation scheme used in later editions of Windows 9x (95 OSR2, 98, 98 SE, and Me), the maximum number of clusters in any one partition is just under 4.3 billion. 

But no matter how many clusters can be created, when the partition size increases, there can't be any more - so the only thing that can change is the size of each cluster.

Under FAT32, cluster sizes range from 4 KB (the smallest) to 32 KB (only Windows NT and 2000 can use larger, 64 KB clusters), depending on the size of the partition.

This next bit makes more sense if you understand how PCs store data. When you write a file to disk, the operating system tries to find enough blank space so that the file can be written to clusters that are contiguous (right next to each other on the disk surface). That makes it faster to retrieve them when needed. However, once the disk begins to fill up, or you edit a file to make it smaller or larger than it was originally, something has to be done (otherwise your hard disk would rapidly fill up with unusable blank space that was too small to take a whole file). Instead, the file is broken up into fragments and stored in pieces wherever the operating system can find spots big enough to take them. It adds pointers in the file table that in essence say, the file starts here, then part of it is over there ... and so on.

But what happens when it reaches the end of the file and the remaining fragment isn't large enough to fill a whole cluster? It can't start another file in the same space. Once a cluster has any data in it, it is considered occupied and no longer available. The larger the cluster size is, the more likely it is that many of them won't be filled up. Once they reach 16 or 32 KB in size, many of the files stored in your computer will fit inside a single cluster with room to spare. And that's room you can recover by making the partition sizes - and therefore, the cluster sizes - smaller.

Destructive

We left off last week by pointing out that with a new computer, coming as many do with a large hard drive packed with lots of software, it is difficult to repartition the drive using Microsoft's FDISK, because the program is destructive. When it creates new partitions, it clears the file allocation table on each partition, and although there may have been data on the disk that is still there, it becomes invisible (and only quick action, use of a program such as Norton Utilities, and extreme luck will ever get it back).

Let's leave the question of why many computer manufacturers are shipping huge hard drives without partitioning them to another day (it's less time-consuming and therefore less expensive). They do, and until consumers begin demanding that they don't, they'll continue to do so.

So, you get a choice. Waste up to 30 per cent of the drive's space, or fix the problem. You could try making an exact copy of your current hard drive, using Symantec's Norton Ghost or Power Quest's Drive Image, then using FDISK to repartition the drive, then restoring its contents. Sadly, this only works properly if all the data on your (unpartitioned) drive will fit within the smaller partitions you're planning to make.

There's a Better Way

However, there are two products that provide a better (faster and safer) way: Partition Magic (now in version 6.01 from Power Quest), and System Commander 2000 (from V-Communications). In addition to allowing you to carve your hard drive up into smaller portions, each allows you to change file allocation systems (so long as your operating system supports the type to which you want to change), and to load multiple operating systems on the same computer.

And the good news is that both cost less than $100.

Side-by-side comparison: Both products support switching from FAT16 to FAT32 or back, and WinNT/2000's NTFS (NT File System). Both support Linux EXT2 partitions as well as UNIX. Partition Magic adds the OS/2 file system, HPFS (High-Performance File System).

System Commander 2000 requires you to have DOS or Windows 95/98/Me installed to start with, while Partition Magic also works when you have Windows NT (service pack 4.01 or later) or Windows 2000 as the sole operating system on board.

Both can make use of any combination of IDE (528 Mb or less), EIDE, or SCSI (Small Computer Systems Interface – pronounced "Scuzzy") drives without an upper size limit.

Both ship with a separate program to allow you to boot your system into multiple operating systems, so that you could, for example, as I have done, set up a system that runs Windows 98 SE, Windows Me, and Windows 2000 (but, of course, you have to have the OS present). You could add Linux and others.

Both allow you to convert a drive from either FAT (16 or 32) to an NTFS volume and back (Win2000 doesn't allow you to revert).

Both come with an anti-virus package to keep your drive(s) master boot record(s) clean.

Partition Magic allows you to re-size clusters and will undo partition deletion or re-formattting. It also lets you split and merge partitions and move unused space to another partition – and to do any of these operations "on the fly." You can change drive letters to maintain Windows Registry settings, or when you move applications from one drive letter to another, PM will update the drive letter assignments. During the process of partitioning or setting up a multi-boot operation to use more than one operating system, both Partition Magic and Boot Magic (which ships with it) make a "rescue" disk set in case something goes wrong later.

System Commander 2000 will undo partitioning. Installing another operating system is an automated process (Partition Magic's is manual, but well-documented).

I found both programs at Future Shop Online (www.futureshop.ca). Partition Magic: $69. System Commander 2000: $79.

Last note: Yes, Symantec once had a product it acquired when it purchased Quarterdeck, called Partition-It, but the product no longer appears to be available.

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