ReadyBoost in Vista

Can someone explain to me how it works?
This is how swap works in linux too?
They use the USB drive space to create virtual memory?

I read a few articles online about ReadyBoost. But, they are too professional for me. I dont know what is a cache.

 

Swap in linux and virtual memory in windows are files that are unloaded out of the ram and stored on hard disk. This happens mostly if the ram is full.

Readyboost uses flash driver. USB or a flash card. Compared to hard disks flash drivers have much slower transfer rate but much lower seek time. Seek time is the time it takes to find and access a file. Seek time can be compared to skipping tracks on a CD player. It takes time to find the next track. Virtual memory is often made up of many small files. Hard disks are bad at copying many small files. The harddisk head has to keep moving and this movement takes longer then the transfer. This is where flash is good since the seek time is almost 0 because there is no repositionening of moving parts.

Readyboost now optimizes and puts the small many files on the flash drive and the big files on the hard disk. This takes advantinge of the low seek time of flash and the high tranfer rate of hard disks.

 

ReadyBoost uses flash memory in the form of a SD card, an USB key etc. as a buffer (cache) for the hard drive, storing recently used files in the flash memory. This results in the system not having to access the relatively slow hard drive (compared to flash memory) as often, which can improve performance. Performance increase by using ReadyBoost will probably be more noticeable the less RAM you have.
That's the basic idea of how it works, hope it helped you understand it better.

I'm no Linux expert, so I won't go into how swap works on Linux, but I don't think it's the same thing.

Edit: Too slow! :|

 

i see. So, Vista uses USB stuff for flash memory to store recently work to increase performance.

is it bcoz the hard drive size is smaller so they have better seek time?
so, a 120 GB portable hard drive or 8 GB USB key dont help much?

 

8GB USB flash drive would help if its fast enough. I would say that 2GB of flash is enough. Portable hard disks dont help at all. They are slower then internal drives.
The seek time does depend on the size some what but mostly it is because flash doesnt have any moving parts that has to get into the right position before reading or writing data.

 

ReadyBoost Q&A:

http://blogs.msdn.com/tomarcher/archive/2006/06/02/615199.aspx

 

thanks guys. i now understand clearly.

 

Unless, you know, it's a Zune, iPod, Walkman, iAudio... etc.
Those don't use Plays For Sure.

Good link, though. Thanks.

 

If Vista does tap into -say a 4gig flash drive- for ReadyBoost, does it leave any record on the drive, or is all the data deleted once the action is finished?

I just read that with a SSD, it can be partitioned to accommodate readyboost, making it seem to me that the cache is saved on the disk in some form.

So, is it deleted, or saved on the disk (have to be manually deleted)?

 

No, the drive use is encrypted with and AES-128 security encryption. So if you took it out and gave it to someone else, they wouldnt easily be able to read it