[X4U] What is private>var>vm>swapfile?

[Neil Laubenthal]

On Dec 5, 2007, at 20:49, Mark Des Cotes wrote:

> I'm using WhatSize to help me clean out my hard drive. I notice an  
> invisible folder on the HD called "private" that is 2.3 GB in size.  
> The main culprit inside is a folder called "var" which in turn  
> contains the folder "vm" which holds a bunch of files titled  
> "swapfile#" Can someone tell me what these folders are for? Do they  
> need to be that big?


They're virtual memory files. All unix based operating systems use  
them and they get created when needed; with more being created over  
time. When you reboot the old ones get deleted. This is one of the  
reasons you need to leave free space on your boot drive. The size  
starts with a 64 MB one but they get progressively bigger. There will  
also be a sleepimage file in the same folder . . . it gets created  
whenever the machine goes to sleep and is the same size as however  
much installed RAM you have.