Partitioning Questions

These may sound like dum questions to some of you, but if someone could quickly explain or link me to an explanation i'd be most greatful.

What is really going when a hard drive is partitioned ?
... and why does it need to be partitioned

What happens when logical partitions are created ?
.. and why do they need to be created ?

What happens when extended partitions are created ?
.. why do they need to be created ?

What is happening when a partition is formated ?
... and why does a partition need to be formatted before being used?


Thanks in advance !

What is really going on when a Hard Drive is partitioned:


When you partition your HDD you are simpily dividing your hard drive into different sectors which can be treated as a seperate hard drive should you so wish.

Each partition has a Volume Boot Sector that contains a Volume Boot Code and a Disc Parameter Block.

A Volume Boot Code is used to initiate the load of an Operating System and is unique to that O/S. It is stored in the master boot record(which your hard drive will have one of no matter how many partitions you have). This only happens for a primary partition that is active.

So say you have three partitions C, D and E. Windows is on C.

When you turn your computer on and the proccessor and BIOS do their bit , the BIOS needs to know where and what to boot from your hard drive, so at the very begining of every hard drive is the Master Boot Record.
Your BIOS will load its boot program here and then read exactly what partitions your drive has, what O/S it has and where the partition start and end.
This is where third party boot loaders are stored and you may be given an option of what O/S to load, Linux Windows etc if you have more than one O/S.
This is where the Volume Boot Code is read hence the O/S you selected will start to load.(this is also a favorite place for viruses to hide themselves as it is one of the first things to be booted!)

A disc parameter block simpily contains infor mation about the specfic partition, Size, label name, amount of clusters sectors etc. It just lets what ever wants to know about the specs of that partition.


You can have a maximum of Four Primary partitions of a Hard Drive due to the way the MBR is wrote.
A primary partition is really any partition that is bootable (has an O/S loaded on to it).
So say you have four partitions C D E and F windows is loaded on C and Linux is loaded on E
C and E would be your Primary partitions and if you choses to boot windows up C would also now be your Active partition as that is what you are working from.

Now say you format C and D and they are now both NFTS and you install windows XP and the C drive.
Windows will recognise the D drive as is has a file system on it that it can use hence it will let you store thing on it, D is now a logical drive.
You can have upto 24 logical drives within a extended partition.

If you have logical partitions then you will have an Extended partition.
An extended partition containes all logical drives with the primary partition (remeber C is the primary partition as this is where you loaded windows to)

So you have

C (windows).......{Extended partition .... D...}

There is more to it than this but this is the billy basic of partitioning in a (hopefully) simple form!

Hope it helped you understand more!?!?

//edit: this site may help you some more; http://www.pcguide.com/ref/hdd/file/...titions-c.html

Thanks a lot, that was exactly what i was looking for.