What is the difference between SMARTDRV and Virtual Memory?

w^rl0rd

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Webmaster

smartdrv is a left-over from the dos/win3.x days to speed up disk read and/or write access by assigning RAM for the disk to use.

Virtual memory (also page file or swap file) is vice versa actually, it's a typcally a file on your harddisk that can be used by the OS as if it was RAM.

lazyart

Interesting question... they are "opposites":

SMARTDRV uses RAM for drive space, virtual memory uses the hard drive as RAM.

Use SMARTDRV to keep some of the hard disk data in memory in anticipation that the system will need it. Instead of grabbing it from the hard drive, it may be pulled from memory (if it is the correct info) which is a lot quicker. It's used in DOS, but does make an appearance when you are installing Windows.

Virtual Memory on the other hand, is used in Windows. When you are juggling more programs than you can fit in memory, Windows will **** memory that it's not using at the moment onto the hard drive to make room for what you need now. It will swap back and forth to give the appearance of having more memory than you actually have. The file on your hard drive where this info is stashed is called the Windows "Swap File"-- win386.swp (win9x) or pagefile.sys (NT,2K,XP). Constant or excessive swapping (called "thrashing") is a sign that a memory upgrade is needed.

HTH.

lazyart

figures this q would be answered while i typed. Oh well. Did someone request "Maximum verbosity?"

Webmaster

I like your answer better

bellboy

smartdrv comes into its own when installing an operating system. have you tried installing an operating system using a boot disk that did not have smartdrv and then installing the same operating system using a disk that didn't?

i remember installing the microsoft eval version of windows 2000 advanced server on a machine in my lab, and the time it took the setup program to copy about 16% of the files required for installation was the time it took setup using smartdrv to copy all the files and reboot for the final time.

w^rl0rd

O.K. Not to beat a dead horse, but isn't SMARTDRV somewhat like disk caching? I mean, when data is requested, and that data is stored in cache, it speeds up the retrieval by not relying on the slower reads from the disk.

Is SMARTDRV an older version of disk caching? Isn't modern disk caching done on the drive itself?

lazyart

Yes, smartdrv is exactly that. Drives today have as much as 8MB of onboard cache/buffer (although 2MB is more common) but still nothing is quicker than RAM.

Drakonblayde

Most people seem to think that smartdrv is obsoleted by VCACHE. Try deltreeing your temp inet files, history and cookies without running smartdrv in a dos window beforehand. It's a greate excuse to take a coffee break

(and for those that wonder, no, I don't trust the little buttons in Internet Explorer. I do trust the destructive power of deltree

)

w^rl0rd

But what about today? Why is VCACHE neccessary when hard drives have cache buffers?

trick000

I can't seem to find smartdrv or vcache in XP. Is it available in XP at all?

w^rl0rd

If I'm not mistaken, isn't disk caching still done in RAM?