How many partitions
 

How many partitions i need ?
What should be their names?
What size should i assign them?i have 4 GB of free space.

The amount of partitions is really up to you. I would put the bulk of my disk space in the / partition. I usually allow my distro to do it's work and make the number of partitions it wants. Otherwise, I go ahead and make 2; a / and a swap. The rest is up to Linux and Mandrake. Your swap should be about double the size of RAM you have installed (if 64, then make swap 128 and so on...).

You should give a little more info like what distro you are installing, and maybe what file system you are planning on using. There is really no huge benefit to making 30+ partions if you are just planning on using your LinuxBox as a home PC for games and internet. As a server, I have no idea.

Actually, if you do a normal workstation-class install most distros will take care of all of this for you, usually by creating one root partition and a small partition for swap.

If you're just getting into Linux, you don't really need to get complicated with your partition scheme.
The basic scheme is:

1 swap partition - not larger than 256M, unless your running a server or other very intensive tasks. The rule of making swap twice the size of your RAM is outdated for the amount of memory in today's machines.

1 root partition (called simply " / ")- the rest of the space on the drive.

There are, of course, many other schemes, but there's really no single correct one.

Im installing redhat 7.0
is /boot partition necessary ,remember i have also windows installed and i want to have both operating systems

Well, you can have /boot directory on seperate partition to the rest of the directories listed under / (root/top-level directory). But that would make it a bit more complex. So in other words I'd use this scheme:

/ (root/top-level directory)- 3GB - 3.75GB
swap - around 200-300MB (depending how memory intensive the application(s) is/are)

Cool, I didn't know that the swap thing was "outdated".

I have a question then.

If I were to have, say a Gig of RAM would I not have a swap file? Thanks.

It really depends on what you will be doing with your system, but you could probably get away with no swap partition. However, with 4 GB of space, you probably wouldn't 256MB of space for a swap partition -- and I would make it a swap partition, not a swap file.

Hell, even with my wimpy 256M of RAM my swap hardly ever gets touched. Granted, my systems are just workstations, not servers, but still....
:)