On Aug 28, 2012, at 6:09 AM, Jack Coats wrote: > Once virtual memory was being used we 'paged'. Read/wrote one page at > a time. Shortly after we started using swapping to take a 'set of > pages', normally defined by a 'reasonable buffer' for the underlying > device. This was especially true a devices were addressed by > cylinder/track/sector addressing. When the linear addressing of > devices (a good thing) obfuscated the hardware using onboard micro > controllers, and the underlying architecture of the drives were > obfuscated further, add in larger on-device buffers that can help > buffer reads and sometimes writes, the optimization for device became > harder and less needed than before. > > Now we basically do no paging, and only swap.
I'm just going back through this thread, and wanted to pick a small nit. IME, "paging" is when same-size segments of memory (pages) are transferred between RAM and disk (or other backing store); "swapping" is when the entire memory space of a process is transferred. Wikipedia and other sources confirm this usage. What we do now is actually paging, not swapping. Systems haven't regularly swapped for many years, although nowadays, people tend to use the terms interchangably (or in fact, prefer "swapping" over "paging"). -------------------------------------------------------------------- Leon Towns-von Stauber http://www.occam.com/leonvs/ "We have not come to save you, but you will not die in vain!" _______________________________________________ Tech mailing list Tech@lists.lopsa.org https://lists.lopsa.org/cgi-bin/mailman/listinfo/tech This list provided by the League of Professional System Administrators http://lopsa.org/
