SWAPPER.DAT

by Britton Turnbull

OS/2 is a mature environment that has improved over time. It has now reached a stage where internally the system will dynamically optimise itself.

OS/2 uses a disk file named SWAPPER.DAT to store software when the real RAM is insufficient. This is called VIRTUAL memory, as the swapper.dat file looks like ram, but is not.

So when you load an application and you have insufficient memory, OS/2 will copy memory contents to the swapper file, and then use the real ram for the new program to operate in.

You would expect OS/2 to then copy the old memory contents back into memory when you close the application, but OS/2 is intelligent enough to realise that this may not be necessary. It will load data from the swapper file, when YOU the user select an application that resides in the swapper file.

Typically software modules that are dormant are moved to the swapper file, and active modules are retained in real RAM.

This means that if you start your working day in a word process and spreadsheet environment, with little contact to the outside world, OS/2 will adjust to this environment. Then if you start to access a Network or the Internet, OS/2 will bring necessary modules into real RAM, and relegate dormant software to the swapper file.

You will always have a responsive system with few pauses as in other environments. The only noticeable activity is when you activate a dormant application, then the disk will be active for a few seconds.

If you find that the way you are using your computer triggers a large amount of drive activity, consider adding more RAM, or change your ways.