Hi i'm very new linux and thinking about installing redhat as a third operating system on my computer!
as i've done some research on it i've read about a 'swap disk' that linux uses and my question is whether i need to create this swap partition myself usind 'fdisk' or some software like partition magic?

Welcome to LQ.org, MichaelW!

I wouldn't use partition magic. At best those tools are graphical front ends for the tools like fdisk. At worst they're something completely different.

When you install linux, it will ask you to create a swap partition. This should usually be around twice the size of your system's RAM. (I have 128MB on my laptop so I created a 256MB swap partition).

Please look around the forum for issues on NTFS and linux filesystems. Mostly NTFS can only be accessed read only (although many people claim to be able to use the experimental read-write driver w/o problems). FAT32 is much more desirable to enable reliable access from linux partitions.

If you're new to linux, try Redhat of Mandrake. Don't go for Slackware or NSA Security Enhanced Linux yet.

Have fun. And before you jiggle partitions make backups of essential stuff.

Bert

What Bert said, and a bit more...

If you have loads of RAM, then the rule of thumb kinda breaks down. E.g. it's a bit daft to have a 1GB swap space if you have 1/2 a GB of RAM.

I have gotten on fine with a 256MB swap partition in computers with RAM varying from 128MB to 512MB.

If you have 512 MB RAM i wouldn't even create a swap partition. I've done this when I only had 256 MB RAM and I did everything in X (except play 3d games) and it ran smooth and wasn't slow at all.

I've recently had a bit of a flame session with someone over at Linux Professional Institute about this - it came up in an exam question, and none of the given answers were correct. There is a curve for the relationship between RAM and swap space.

To understand, you need to look at what swap space is used for and how well it's used by your kernel version. I used to have 1:1 for RAM:swap for Redhat 6.2 and most of the time it did nothing.

By the time 7.1 came around, the swap was being used properly. When your system swaps 'pages' in and out of memory, it obviously needs some dedicated space to do this. When it doesn't have enough, it starts 'thrashing' - swapping pages in and out without doing any work. If you have too much, it just doesn't get used.

Still it's always best to have too much. Hell if you're running a 120GB disk, you won't miss 1GB, even if not all of it's used.

And since 2.2.x I believe linux uses the swap space quite aggresively - as it should. I'd say for a 512MB RAM machine, 700MB swap is good.

Bert