"kim kubik" <[EMAIL PROTECTED]> writes:
> There are (at least) two overlapping meanings of the phrase "virtual
> memory" here: a virtual (i.e., non-real) memory address and a
> virtual eXtention ("X" as in VAX) of memory out to disk. Most
> people seem to use the latter meaning.
>
> The first, virtual memory addressing (dividing up of RAM into fixed
> sized pages) is in most cases a big win: drastic decrease in memory
> fragmentation.
>
> Extending RAM out to disk pages adds all the cute PhD thesis project
> benchmarkable optimizations: page size, replacement algorithms,
> thrash minimization, etc. In an early attempt a compiling TeX in SUN
> the person finally shut down the machine after 36 hours, noting the
> paging daemon was taking up more and more of cpu time and eventually
> might take all of it.
the post did describe a case where virtual memory was used
to address fragmentation problem
http://www.garlic.com/~lynn/2006i.html#22 virtual memory
some subsequent drift on this thread in a.f.c.
http://www.garlic.com/~lynn/2006i.html#23 virtual memory implementation in
S/370
http://www.garlic.com/~lynn/2006i.html#24 virtual memory implementation in
S/370
i had done a bunch of the paging stuff as an undergraduate in the 60s
... which was picked up and shipped in cp67 product.
http://www.garlic.com/~lynn/subtopic.html#wsclock
decade plus later there was some conflict around somebody's stanford
phd on global lru replacement (work that i had done as an undergraduate in
the 60s) vis-a-vis local lru replacements. some past posts mentioning
the conflict.
http://www.garlic.com/~lynn/93.html#4 360/67, was Re: IBM's Project F/S ?
http://www.garlic.com/~lynn/94.html#49 Rethinking Virtual Memory
http://www.garlic.com/~lynn/2001c.html#10 Memory management - Page replacement
http://www.garlic.com/~lynn/2002c.html#49 Swapper was Re: History of Login
Names
http://www.garlic.com/~lynn/2003k.html#8 z VM 4.3
http://www.garlic.com/~lynn/2003k.html#9 What is timesharing, anyway?
http://www.garlic.com/~lynn/2004g.html#13 Infiniband - practicalities for small
clusters
http://www.garlic.com/~lynn/2004q.html#73 Athlon cache question
http://www.garlic.com/~lynn/2005d.html#37 Thou shalt have no other gods before
the ANSI C standard
http://www.garlic.com/~lynn/2005d.html#48 Secure design
http://www.garlic.com/~lynn/2005f.html#47 Moving assembler programs above the
line
http://www.garlic.com/~lynn/2005n.html#23 Code density and performance?
http://www.garlic.com/~lynn/2006f.html#0 using 3390 mod-9s
i had also done this stuff with dynamica adaptive scheduling
(scheduling policies included fair share) ... and scheduling to the
bottleneck
http://www.garlic.com/~lynn/subtopic.html#fairshare
much of it was dropped in the morph from cp67 to vm370 ... but
i was allowed to reintroduce it as the "resource manager"
which became availble 11may76
http://www.garlic.com/~lynn/2006i.html#26 11may76, 30 years, (re-)release of
resource manager
around this time, i was starting to notice the decline of relative
disk system performance ... and significant increase in amount of
available real storage ... and being able to start to use real storage
caching to compensate for the decline in relative disk system
performance
i started making some comments about it and the disk division
eventually assigned their performance group to refute the comments.
the performance group came back and observed that i had slightly
understated the problem.
misc. past posts on the subject:
http://www.garlic.com/~lynn/93.html#31 Big I/O or Kicking the Mainframe out the
Door
http://www.garlic.com/~lynn/94.html#43 Bloat, elegance, simplicity and other
irrelevant concepts
http://www.garlic.com/~lynn/94.html#55 How Do the Old Mainframes Compare to
Today's Micros?
http://www.garlic.com/~lynn/95.html#10 Virtual Memory (A return to the past?)
http://www.garlic.com/~lynn/98.html#46 The god old days(???)
http://www.garlic.com/~lynn/99.html#4 IBM S/360
http://www.garlic.com/~lynn/99.html#112 OS/360 names and error codes (was:
Humorous and/or Interesting Opcodes)
http://www.garlic.com/~lynn/2001d.html#66 Pentium 4 Prefetch engine?
http://www.garlic.com/~lynn/2001f.html#62 any 70's era supercomputers that ran
as slow as today's supercomputers?
http://www.garlic.com/~lynn/2001f.html#68 Q: Merced a flop or not?
http://www.garlic.com/~lynn/2001l.html#40 MVS History (all parts)
http://www.garlic.com/~lynn/2001l.html#61 MVS History (all parts)
http://www.garlic.com/~lynn/2001m.html#23 Smallest Storage Capacity Hard Disk?
http://www.garlic.com/~lynn/2002.html#5 index searching
http://www.garlic.com/~lynn/2002b.html#11 Microcode? (& index searching)
http://www.garlic.com/~lynn/2002b.html#20 index searching
http://www.garlic.com/~lynn/2002e.html#8 What are some impressive page rates?
http://www.garlic.com/~lynn/2002e.html#9 What are some impressive page rates?
http://www.garlic.com/~lynn/2002i.html#16 AS/400 and MVS - clarification please
http://www.garlic.com/~lynn/2003i.html#33 Fix the shuttle or fly it unmanned
http://www.garlic.com/~lynn/2004n.html#22 Shipwrecks
http://www.garlic.com/~lynn/2004p.html#39 100% CPU is not always bad
http://www.garlic.com/~lynn/2005h.html#13 Today's mainframe--anything to new?
http://www.garlic.com/~lynn/2005k.html#53 Performance and Capacity Planning
http://www.garlic.com/~lynn/2005n.html#29 Data communications over telegraph
circuits
--
Anne & Lynn Wheeler | http://www.garlic.com/~lynn/
