Should I use "quick" format, and what is quick format anyway?

Full Format

When you format a disk without specifying that it is to be a "quick" format, it becomes a full format. A full format:

• Writes control information to the very first sectors of the drive.

• Creates an empty "root" directory of files and folders on the drive.

• Depending on the format chosen, may write additional file system overhead information, as well as the initial volume label on the drive.

• Writes data to every sector on the drive, and marks as unusable any sectors which fail to be written to.

It's that last step that takes all the time. Essentially a full format writes data to every possible place that data can be stored on the drive. The side effect, of course, is that whatever was written there before is overwritten.

Quick Format

You can probably guess that a quick format is everything a full format is, except for the last step. It:

• Writes control information to the very first sectors of the drive.

• Creates an empty "root" directory of files and folders on the drive.

• Depending on the format chosen, may write additional file system overhead information, as well as the initial volume label on the drive.

In this case, the surface area of the disk is not overwritten, and whatever was stored in those areas of the hard disk remains.

Quick versus Full

It's worth reviewing that when you delete a file on the disk, the actual data that is stored on the disk is not removed - rather, the directory entry that says "this file's data lives here on the disk" is removed. The area that holds the actual data becomes part of the disk's free space and may then be overwritten if it's used to hold data for another file sometime in the future.

One metaphor is that it's kind of like moving out of an apartment. You can simply take your name off the door or list of residents, so your apartment is now "free". But if you've left all your stuff inside the apartment anyone can come along and take it. If someone else moves in, they'll get rid of your stuff, but until they do - there it sits. If you don't want people to have your old stuff you need to take the extra step of actually moving it out.

Formatting a hard disk is pretty much the same, except you're working on the entire building at once.

A quick format is sort of like simply taking the list of residents off of the front door and declaring the building empty. A full format takes the extra step of actually emptying the apartments of all their contents.

(Remember, it's a metaphor - it doesn't hold exactly - but it's a fairly simple way to get the overriding concepts. If we were to try to extend it we'd also start removing and moving walls while leaving all the stuff inside )

Quick or Full: Which do you want?

Nine times out of ten, a quick format is sufficient. It's perhaps the fastest way to delete everything on a disk, and is very convenient for that. There's no need to take the extra time to write to every spot on the hard drive.

There are a couple of times when a full format might be a good idea, but even then there are alternatives for each:

• You just got a new disk. A full format ensures that no one else's data is on it, and takes the extra step of identifying bad sectors before you start using it.

• You're about to give the machine or disk away, or dispose of it. In this case, you really do want to erase not just the list of file names, but also overwrite the actual data on the drive so that it's not accidentally recovered.

All that being said, CHKDSK is a fine utility that you can use to scan your hard disk for errors at pretty much any time, and tools like SDELETE or DBAN are tailored to erasing information from the hard disk securely.

Formatting Flash Drives

As I said, flash drives are a special case.

The problem is that flash memory wears out the more you write to it - and a full format writes to all of it.

The result is that I would not perform a full format of a flash drive unless you had a very pressing reason. (I'd also not use tools like SDELETE to write multiple times to "securely" erase files, as that is meaningless on flash memory - overwriting once is enough.)