Linked by Thom Holwerda on Mon 11th May 2009 20:43 UTC
Windows SuperFetch is a technology in Windows Vista and onwards that is often misunderstood. I decided to delve into this technology to see what it is all about, and to dispel some of the myths surrounding this feature.
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RE[4]: Test Canedidate
by lemur2 on Tue 12th May 2009 10:54 UTC in reply to "RE[3]: Test Canedidate"
lemur2
Member since:
2007-02-17

Thom:

Windows XP introduced PreFetch in 2001.

But anyway, Tom's Hardware article was about Vista and the advantages of SuperFetch, and they used, among other applications, Writer as an example. It wasn't about Writer itself.


OSGuy:
lemur2, no offense but I am failing to see the point you are trying to make? We are talking about SuperFetch and memory management and this has nothing to do with an ordinary pre-loading. Please clarify?


Pre-fetch isn't Superfetch, but it was a predecessor.

http://en.wikipedia.org/wiki/Prefetcher

Superfetch didn't make an appearance until Windows Vista.

http://en.wikipedia.org/wiki/Windows_Vista_I/O_technologies#SuperFe...

In Windows Vista, SuperFetch and ReadyBoost extend upon the prefetcher and attempt to accelerate application and boot launch times respectively by monitoring and adapting to usage patterns over periods of time and loading the majority of the files and data needed by them into memory so that they can be accessed very quickly when needed.


Preload is more like Superfetch than it is like Prefetch.

http://en.wikipedia.org/wiki/Preload_(software)

preload is a Free Linux program written by Behdad Esfahbod which runs as a daemon and records statistics about usage of programs using Markov chains; files of more frequently-used programs are, during a computer's spare time, loaded into memory. This results in faster application startup times as less data needs to be fetched from disk.


Both preload and Superfetch use previously collected frequency of usage data to determine exactly what to pre-load into RAM, whereas Prefetch doesn't AFAIK.

PS: It is interesting to note that Microsoft bothered to get a patent for ReadyBoost, but they didn't do so for SuperFetch. Damn prior art!

The tricks for success are:
(1) make sure that the time the preloader uses is indeed spare time
(2) pre-load the optimal data and no more
(3) make sure that the system knows what stuff is already in RAM, so it doesn't have to re-load it, and
(4) don't throw away potentially useful pre-loaded data too early.

Edited 2009-05-12 11:06 UTC

Reply Parent Score: 2