Bill and Hen, how do ever thank you for all the learning experience I have had since joining the group. I feel so fortunate . And while I am at it, Harry, do extend to Jerry Freeman my thanks for a terrific presentation. I do not have photoshop, but I learned a great deal. Marta On Apr 29, 2004, at 9:53, Henri Yandell wrote:
> > On Windows it's called Virtual Memory and is an option you can modify. > On > Linux it's something you choose the size of when setting up the system > and > is called swap [probably the same for most UNIXes]. > > As a real easy one liner: > > "Swap/Virtual-memory is when the computer runs out of real memory and > has > to use the hard drive as very slow pretend memory" > > The existence of a swap file is not necessarily bad, it's probably not > using it, but when you switch applications and hear your computer > 'churn', > it's often due to swapping. [Not when you open a new application > though]. > > Obviously things get bad if you're running low on hard drive space. > This > is why a swap file often exists before you need it, so that using up > your > hard drive doesn't suddenly mean you have no swap left. > > On my machine, I seem to have 256M of swap. It also has 766M of memory > or > some such, so it thinks it has 1024M [1G] of memory available and will > churn slowly from 766 upwards until it runs out. It does still run out > though, I've not seen an OS that expands its swap as needed as that > usuallly requires a reboot. > > Hen > > On Thu, 29 Apr 2004, John Robinson wrote: > >> Bill, >> >> Many thanks, like Marta I am glad to be educated on this, and yes she >> was right there were others of us that needed this and just didn't >> have >> her guts to ask. >> >> John R. >> >> >> On Apr 29, 2004, at 9:25 AM, Bill Rising wrote: >> >>> On 4/28/04 19:37, Marta Edie wrote >>> >>>> Well, here comes the ignorant old lady again. I know you know it >>>> all, >>>> but I have no idea what swap files are. And where do you find them >>>> and what are they supposed to do and are or are not doing? And what >>>> garbage is not collected? I am sure there are others on this list >>>> who >>>> don't know and would like to, just don't have my fortitude in >>>> asking. >>> >>> Launching applications, opening documents, surfing the web all cause >>> the >>> operating system to allocate memory to hold relevant data and >>> commands >>> to >>> process the data (such as where windows are and what they need to >>> display). Typically, this memory comes from RAM (random access >>> memory) >>> of >>> some sort. If the computer needs to allocate more memory than it has >>> in >>> RAM, it moves some of the non-recently used info into Virtual Memory >>> (VM), which is really in a file on a disk. Since memory is being >>> swapped, >>> the files which hold the stuff in virtual memory are called swap >>> files. >>> >>> Large amounts of swap files is worrisome on a machine with a lot of >>> RAM, >>> because there should be little need for the swap files. If there are >>> too >>> many, it might be because applications are not telling the operating >>> system that they no longer need the memory they asked for, and they >>> keep >>> asking for new memory (this is a memory leak), or because memory is >>> not >>> deallocated when applications quit (lack of garbage collection). >>> >>> This info could be wrong in the details, because it is inferred from >>> reading, and not from actually reading up on how memory allocation >>> works. >>> Still, it should be roughly correct. >>> >>> Bill >>> >>> >>> | The next meeting of the Louisville Computer Society will >>> | be May 25. The LCS Web page is <http://www.kymac.org>. >>> | List posting address: <mailto:macgroup at erdos.math.louisville.edu> >>> | List Web page: <http://erdos.math.louisville.edu/macgroup> >>> >> >> >> >> | The next meeting of the Louisville Computer Society will >> | be May 25. The LCS Web page is <http://www.kymac.org>. >> | List posting address: <mailto:macgroup at erdos.math.louisville.edu> >> | List Web page: <http://erdos.math.louisville.edu/macgroup> >> > > > > | The next meeting of the Louisville Computer Society will > | be May 25. The LCS Web page is <http://www.kymac.org>. > | List posting address: <mailto:macgroup at erdos.math.louisville.edu> > | List Web page: <http://erdos.math.louisville.edu/macgroup> > | The next meeting of the Louisville Computer Society will | be May 25. The LCS Web page is <http://www.kymac.org>. | List posting address: <mailto:macgroup at erdos.math.louisville.edu> | List Web page: <http://erdos.math.louisville.edu/macgroup>
