Hi all, I might not be a UNIX (Linux) guru yet (if ever), but I do know a thing or two about OS handling.
As someone (sorry I dumped the mail so I can't use your name) pointed out correctly: Swap partition=Total memory requirements - Available memory Now if anyone can tell me the correct value for "Total memory requirements" I would be very pleased because I also need to know the length of a piece of string. For quite a few systems, the "recommended" size of the swap partition (AKA virtual memory) is 1.5 - 2 times the available memory. This is not because of some magical relationship between the amount of memory required and the amount of money spent on memory, but rather due to 2 basic concepts: 1) If you have an active system and you need a large amount of virtual memory, then the probability that the memory required being swapped out is fairly high. This means that the time that the system spends swapping can become more that the time spent on "useful" processing (all depending on the access speed on the swap device, transfer rates, etc.). When this becomes acute the system starts "thrashing" at which time, for all intents and purposes, the system is unavailable and must be rebooted. If the virtual memory is capped then the system will just say "no way" before a dangerous swap level is reached. Given the typical physical constraints on low end devices such as those we find in a UNIX, Windoze, DOS box 2 is about good enough a ratio to use for the swap partition. 2) Whatever people say Apple, IBM, etc. employ some pretty clever people. Originally Apple said we only needed about 64 KB memory, IBM said 640 KB (Why back in the good old days I worked on a DEC System-10 which served about 80 users with 128KB RAM, but fast swap devices). If these people can get it wrong, I'm not even going to try. Now given the cost of a hard disk (1GB=US$500 I suppose, which means about 1.5 cents per 32 KB swap partition) and the cost of bringing down a server to repartition and reinstall (say about an hour of a systems administrator, plus an hour for everyone who cannot access the server...) and I think people will agree that it may be a good idea to install a swap partition, even though I don't think I need it, because tomorrow... Sorry I got so long winded but I think that this is a very important subject and I have fairly flame-retardant skin. "Simon Martin"<[EMAIL PROTECTED]> "Old software engineers never die, they just fail to boot" Any Trademarks used in this document are recognized as Registered Trademarks of their respective owners.
