good point. it is weird i didn't pick this up, as i certainly remember when my early systems (Cray and CDC 6600) did real swapping. unix swapped, if i recall correctly, until the VM systems (like Vax Unix) appeared.
On Aug 28, 2012, at 9:18 PM, Leon Towns-von Stauber wrote: > > 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/ ------------------ Andrew Hume (best -> Telework) +1 623-551-2845 and...@research.att.com (Work) +1 973-236-2014 AT&T Labs - Research; member of USENIX and LOPSA
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