rapid boost

15Apr07

In the light of the RAID article published in the preceding edition let me bring to you the readyboost feature brought in by VISTA which incorporates the use of USB flash drive to improvise on the system performance. But before that let me help you out with few other terminologies.

1. VIRTUAL MEMORY – it is important to reiterate that all window OSs, vista included , will always make use of virtual memory, even when memory required by all the running processes do not exceed the ram. Each and every process running automatically gets its place in virtual memory named as pagefile.sys in a partition of disk. It is accessed whenever OS needs to load other important files.
2. PREFETCH – It was introduced by XP . Cache manager manages a list of directories of files used when a program is called. So when a program is called the cache manager stops the execution and it first checks out its own lists and loads the files which it thinks would be needed for the given applications and then it allows the called application to load itself. So the application finds most of the files in the memory itself which lessens the loading time. Again the cache manager directs the disc defragmenter to shift most of the files of the same applications in same region to avoid the delay caused by the disc head to move to different location.
3. SUPERFETCH – This is introduced by the vista. It overcomes the drawback of the prefetch technology. Prefetch improves the efficiency by loading the majority of the data beforehand but has to move the data to virtual memory when other applications are called. So the data from memory keeps loosing and it has to again reload the same when again called.
Here comes superfetch which also traces which application caused the data to be removed so that when that application ends it reloads the lost data on its own so that the user finds the application as responsive as before.
Superfetch also checks how often and when we use the application.
4. EMD – (extra memory device) now this process causes more use of data retrieval from the hard disc however the hard disc is slow. Here we make use of the speed and reliability of a flash drive which is relatively inexpensive and efficient.

READY BOOST PERFORMANCE ISSUE
Now people might say that faster hard disks actually has higher transfer rates to USB flash drive. It is true mostly for large sequential file reads. So ready boost is smart enough to load the larger chunks of data from the hard disc itself. Basically if the drive head of the hard disc has to move substantial amount to find small chunks of data flash drives leads the race. And you need not fear for the security reasons as the data stored in it is encrypted using AES-128. So no leakage of personal data.
P.S. -
• Not all USB drives are readyboost compatible. 2.5 mb/s to read and 1.5 mb/s for write is the minimum requirement.
• Recommended flash drive size is equivalent to the ram size of the system.
• There is no such method devised to use the power of superfetch in XP. So please don’t waste your time finding one.

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