Demystify Defrag please....

[Earlybird]

What exactly is the process of 'defrag' (ing?) a computer?
Does it need to be done, how often and how?
Am I correct in thinking the process will typically take a fairly long time to complete?
Will my computer run differently once it's been done, and if so, how?

Thank you!

If you change or add any programs to your comp.Or delete anything, or just for the hell
of it, parts of your files can be moved, or changed.To defrag, it reputs the files back in order, maybe removing left over parts of old programs.It needs to be done every 2-3 mos.It takes a while, but you dont have to watch it or anything.Scandisk needs to be done every 3-4 mos. Your comp. wont run different, maybe better.

When your computer disk is new all data is written sequentially, making it quick and easy to read back.

After time bits and pieces are deleted, leaving gaps amongst the data. New data is written in these gaps, making the data fragmented and slower to read back.

When you degragment everything is written back sequentially (as far as possible) and makes data retrieval much faster.

The first time you do it it will take a long time. If you do it regularly after that it will be much faster.

Thanks to you both for info.

How do I initiate a defrag? Is it the sort of thing that should be done before going to bed at night?

And what is scandisk, and how do i do it?

Which operating system are you running? (Eg Windows XP/Vista etc)

Never mind - I did a google search and found instructions.

Thanks again for your help.

Windows XP

Here are the instructions I found....for anyone who might be as technically inept as me!

windows.about.com/od/troubleshooting/ss/defrag_7.htm

Scandisk is a different utility to defrag btw.

Scandisk can be run from the DOS prompt (ie Start, Run) and will scan your disk for errors.

Your defrag instructions are good.

Set it off and let your disk chunter for a few hours.

Started the defrag at the time of the messages last night, and now almost 12 hours later, it is still underway! Does that indicate it badly needed to be done?

Earlybird - how big is the disk? The larger and more fragmented it is, the longer it takes. 12 hours is nothing to be concerned about, but 36 hours might be a worry. Is there a progress meter?