1)What is partitioning?
It is the breaking up of a single physical drive into one or more drive letters. Most people buy their computer pre-configured to have one huge, massive drive letter (the C:\) occupying the entire physical hard disk. People who have certain needs, or demands of performance and speed often prefer to arrange the drive into smaller drive letters.

2)How do I do it?
No newbie should attempt it without being well-informed about the hows and possible consequences. The classic way (meaning the inefficient and tedious MS method) is to use a command prompt utility called FDISK.EXE. This a totally destructive and tedious method, intolerant of error or changing your mind about partition layout. 3rd party programs, led by PartitionMagic, make this task graphical and relatively easy to do. Too easy in fact. It makes newbies think that it is a routine and trivial task to alter partition structures on a hard disk. If preserving data is important, then this taks is not to be take lightly. If data preservation is not important, then slice and dice (repartition) with no fear... the worst that can happpen is you have to erase the drive and start again.

3)What does it do?
Partitioning breaks the single physical drive into one or more PRIMARY partitions (up to 4 are allowed), or up to three PRIMARY partitions and one EXTENDED partition, which itself consists of one or more LOGICAL partitions. There are a lot of rules about this... breaking some will leave your OS unbootable or even corrupt beyond repair (e.g, you must wipe the disk & start from scratch).

4)What good does it do?
It allows you to organize your hard drive, and for the few these days that know how the underlying hardware works, you can make your machine a little bit faster and more efficient, to massively faster... it depends on how bad the current setup is, and what you are willing to do, and what OS you run.

Take an example. A fictional 2000 MHz machine. As a general idea, on average, that machine "effectively" performs like a 1200 or 1400 for many people. The just don't "know" it. One 11 year old CS player last month, after spending a few days working on his machine, starting from the BIOS on up, increased his machine's overall performance over 60%. His 3000 MHz machine felt to him like a 4500 MHz machine. The actual clock speeds did not change, only the configuration, updating of software & BIOS, repartitioning (large effect for him), and registry+driver optimization.

But it is not trivial, and takes hours to explain even in person.

So at the moment, the downside probably outwieghs the upside for major system changes for most people... if a machine is running, no matter how poorly, at least it is running (that is the MS guiding philosophy for about 20 years). Hardware and software and driver variations make it an almost certainty that unexpected issues will arise when doing this... and a newbie is ill-equipped to deal with resolving such issues. Not impossible with the advent of Google and MS Knowledge base, but definitely tedious, boring, and hour after hour after hour of toil, frustration, and outright anger when things don't go right. Yelling at a machine does not help. And usually if there was someone else available to do the job or answer the questions that arise, then that person would be doing it in the first place.

Later this month, I plan to make some articles on how to do some basic tasks... but for now, if you are a newbie (which is OK... everyone is a newbie at some point), then do not attempt partitioning until you understand more. This single post is not enough. You can google, if you want to know now.

So bottom line is that I'm saying most readers should NOT attempt things like partitioning just because others do it, unless you have someone in real life that is able to assist, or you do a lot of frontloading (learning up front, before diving in).

I will add a couple of points to Wartrain's answer which may help you understand the benefit of having multiple (logical) partitions on a single drive.

Data preservation: If your OS blows up and you have stored your data on another partition (not your C: drive) you can rebuild your OS on the C: drive without losing your data (assuming your OS hasn't blow up because the HD is bad). It's not an alternative to backing up your data on external media (CD, tape, etc.) but it adds a layer of safety to the protection of your data in the event you don't back up as often as you should.

General ease of recovery, and reduction of maintainance for your system: If, for example you follow Wartrain's guidelines for putting more than one bootable OS on separate partitions, and putting special system files (temp & cache files) on dedicated (small) partitions, it makes it easier to keep all of your drives operating at peak capacity (fewer concerns about file fragmentation on your system disk), ease of defragmentation when you do it, and multiple (recovery) boot options when you encounter a problem with one of the installed OS's.

My 2 cents, anyway. Wartrain can correct me if I've mispoken or missed anything crucial.

[This message has been edited by Chonaman (edited 01-10-2006 @ 10:26 PM).]

I just spent the last 2 hours tonight explaining to one of my borhters in law about how I've fixed his machine in the last four days.... the longest chunk of time was in getting him to understand about his new partitions and the exact 2 points Chonaman posted... separating data/preparing to survive 'disaster', and how to backup/restore the RARed partitions.

His machine is never more than 15 minutes from a fresh install... unless he replaces his motherboard that is. If OS#1 fails, boot to #1, delete all 4 root directories in OS#1, then extract the 4 RARed directories, then reboot. Back to 100% perfect, full install, all programs running. Repartitioning makes that possible.

About a year ago, MS scandisk decided to 'fix' one of my files on a routine boot up in the morning... on the G-drive (My first physical hard drive has drives C, D, E, F, G, H, and I on it). MS damaged the partition in its usual clumsy attempt to "fix" the sick baby by machine-gunning the baby. But this time the machinegun also hit the wall (the partition, in this analogy) behind the baby (the file). Now my G partition was "gone". One last time in my life, I decided to take the easy way out and let Symantec Norton rebuild the partition. When it was done, I had no G, H, or I partitions.

The morals of the story are many, but the point is that if my drive was not segmented (partitioned), all my machine would have been lost. As it was, the I drive (medIa, like MP3s) was gone, H (downloads), and G (3rd emergency boot partition & backup storage) were the only casualties.

On machines like the one tonight, for average users, this is what I typically do for a large (120 to 400GB primary physical drive):

C: 3GB (512B): Emergency Boot. XP + basics, but no games & bloatware.
D: 2GB (1K): Swapfile. Contains ONLY a 1.5GB swapfile. Nothing else. Ever.
E: 6.1GB (1K): Temp. Contains single Temp directory (all users point the TMP and TEMP dirs here in this single spot) and Cache for each user (individual dirs for MSIE, Opera, MBM, etc.).
F: 48GB (8K): Primary OS.
G: 48GB (8K): Data
H: 180GB (NTFS): Downloads, backups, archives

Note: Cluster size is in (). NTFS indexing = off.

Normal boot is to F:\. To back up F:\ boot to C:\, RAR 4 directories (or UnRAR to restore a pristine OS).

The swapfile forced to reside in the outer cylinders, meaning it is as fast as it can ever get on a physical drive. The upper and lower limit are set to 1500GB, creating a static swapfile with no dynamic resizeing overhead. Ever. And no glitches/stutters in 3D shooters. And no fragmentation. All OSs use the same exact swapfile on D:\.

The E:\ contains all files that are transitory, numerous, tiny, etc. Things like program cache, browser crap, logfiles, and especially all temp files (lots of special stuff to edit throughout OS/apps to make this fully happen, though).

The F:\ contains the main OS, which is also forced to reside in the absolute fastest cylinders of the HD. Fragmetation is slow, speed is fast.

G:\ has fairly fast performance, and data is there.

H:\ has from 85% to 60% of the performance of C:\, D:\, E:\, and F:\ (on a 300GB+ drive, that is). Files which do not reqire best speeds reside here.

There is a lot more to it that this, but its an overview. Exact sizes and partition boundaries are adjusted based on the specific hardware (the HD) being used. FAT32 is used throughout, but cluster size is optimized for each individual partition.

Again, this is still not a HOWTO. But if a person knows "how", then this is the general map for "what" to create for a general system.

If a person is going to repartition and needs to save their data (e.g., does not want to totally wipe out the HD and start fresh), then don't repartition. You must back you data up. Be ready to lose everything. If you use Partition Magic 8.05, you probably won't lose it unless there are certain kinds of viruses present.

The cheap way out is to use FDISK.EXE to create the disks. You will not be able to control cluster size, though. The best way for most people is Partition Magic. Buy it and keep it. Its worth its weight in gold. Once you do partitioning, everyone is going to want you to do it, and PM makes it as easy as its going to get.

OK, this thread is now indexed as:

Partitioning your hard drive (general outline) [magic, boot, primary, extended]: 1