Just wondering, what is a swap partition and what is it good for? What happens if the OS is installed without one? whats the advantages and disadvantages of having one present?
Last but not least, how do you determine the size it should be?

Thank you

The swap partition is in effect an extension of the computers ram, if you run out of memory linux will read and write to the swap partition, it should be twice the size of the physical memory and you should make sure you always make swap partitions.

oh i.c, thanx lumber

In addition... A swap partition is similar to a swap file or page file in windows. Advantages / disadvantages are are somewhat based on how your system is used, what kind of applicartions your running and how much RAM you have. Lots of RAM on a desktop installation your swap will probably some or not at all.

Not having swap if you run out of physical memory can crash the OS.

The 2X RAM swap rule IMO is outdated. If you do not have much RAM then go with more swap. With 256mb RAM or over 512mb swap is good enough for the average user.