Superfetch in vista...

[UlricT]

Ok, I know there is a thread about Superfetch (with I bumped), but this info was not there... Was wondering whether you guys had heard of this?

Microsoft's upcoming Windows Vista will allow users to add memory to the operating system through the use of USB memory keys, the company revealed at its Professional Developer Conference in Los Angeles.
The option is part of a technology called Superfetch designed to make the next version of Windows faster to use over time.
Superfetch will monitor the data and applications accessed by the user in recent months and preload those into its memory. This allows for faster access to data and applications.
In current Windows versions the software loads applications and data only as the user asks for it. This takes time because Windows has to load not only the application itself after a system reboot but the drivers and other auxiliary applications.
"Superfetch works great if you have a reasonable amount of memory, and it works fantastic if you have boatloads of memory," Jim Alchin, group vice president for Windows platforms at Microsoft, told delegates in Los Angeles.
"But even if you don't have boatloads of memory, we have thought about that [with the USB option]."

Superfetch adds the memory on the USB key to the system's virtual memory, which in turn is used to preload applications and data which the user accesses frequently. The USB option offers the ability to upgrade the system's memory even if there are no physical memory slots, allowing laptop users to increase system speed, according to Alchin.
The user can still remove the memory key at any moment without affecting system stability. To prevent security issues, the information is encrypted on the key to prevent data leaks.
Superfetch is one of several new ways in which Windows Vista is designed to increase system performance.
Other technologies will automatically defragment the hard disk, and provide a visual tool to allow the user to spot possible bottlenecks in the system's performance.

Cliffs:
1. Use USB keys to add memory to your machine
2. Store application usage patterns on the key, so stuff loads faster

/EDIT: ow on AT news page!

 

[IamDavid]

my bad, looks interesting...

 

[UlricT]

omg I called something, and its on the news page now... (Has a link there)

 

[kamper]

How is putting encrypted data on a usb stick just like adding more ram? What are the average bandwidths/latencies to and from memory/usb key/disk? I would have assumed that usb is much closer to the disk than to memory.

 

[TGHI]

...uh.... that seems like an awful idea on MS's behalf. For running 'optimally' Vista requires a SATA2 drive (which are capable of a 300MB/s burst transfer rate) and at least DDR400 RAM ( 3200MB/s), even using a standard IDE 133 HD you still get speeds gusting to 133MB/s. NOW, compare that to USB 2.0 which is 480Mbits/s ... meaning that the fastest speeds you can achieve are at best 73% slower than the standard IDE drives nowadays. SO: who in their right mind would use a device on USB as RAM when you can have a larger pagefile on a hard drive - or even better: RAM is cheap, why not buy some more?

 

[Mark R]

meaning that the fastest speeds you can achieve are at best 73% slower than the standard IDE drives nowadays

Page file access is inherently pretty much random. This means that for virtually every read the OS makes there's a delay of 10-20 ms. (An age in computer terms - accessing a 2kB chunk of data can take as long as loading 2 MB once the access has completed). Flash memory, OTOH, although limited in bandwidth - has essentially instantaneous access, and this is what counts.

 

[spyordie007]

I think part of the idea with superfetch is that eventually motherboards will have built-in flash memory for storing certain things. Part of the hopes may be that it is quicker than current flash memory. The idea is not just for applications but for OS components as well (so you can make the computer boot up much faster).

I havent followed the superfetch info very closely though; so I could be wrong about this.

Whichever the case may be the last couple of posts make some very important points:
1. If you can increase your RAM it's going to be faster than flash memory regardless.
2. If you have a very fast storage system anyways it isnt going to help.
-2a. Of course laptops have much slower storage than desktops, so this may help more on laptops than desktops

So the moral of the story is to drop a 15k RPM SCSI array in your machine w/ 4GB of RAM and you can (righly) state "I dont care about superfetch!"

 

[kamper]

Originally posted by: spyordie007
I think part of the idea with superfetch is that eventually motherboards will have built-in flash memory for storing certain things. Part of the hopes may be that it is quicker than current flash memory. The idea is not just for applications but for OS components as well (so you can make the computer boot up much faster).

That sounds kinda icky. I don't want an operating system installed on my motherboard, I want it on my hard drive.

But at any rate, built in memory on a motherboard couldn't really be used as general purpose storage could it? I mean, with ram, you can keep adding more up to practical limits. But a fixed size bucket seems out of place. Would this fit between ram and disk in the storage hierarchy? Or would it be a branch, beside ram?

 

[spyordie007]

My guess would be a branch outside of RAM; filling the gap between fast volitile storage and slow(er) non-volitile storage.

I think the idea is that you could "boot" a PC for basic activities (i.e. playing a DVD) "instantly"; if you wanted to run the full-blown OS than it probably wouldnt help as much.

 

[bsobel]

Originally posted by: TGHI
...uh.... that seems like an awful idea on MS's behalf. For running 'optimally' Vista requires a SATA2 drive (which are capable of a 300MB/s burst transfer rate) and at least DDR400 RAM ( 3200MB/s), even using a standard IDE 133 HD you still get speeds gusting to 133MB/s. NOW, compare that to USB 2.0 which is 480Mbits/s ... meaning that the fastest speeds you can achieve are at best 73% slower than the standard IDE drives nowadays. SO: who in their right mind would use a device on USB as RAM when you can have a larger pagefile on a hard drive - or even better: RAM is cheap, why not buy some more?

Guys, to me it appears they are just storing the prefetch information here (see your prefetch dir on your harddrive). This way a) the data is read without moving the heads (prefetch in some ways conflicts with itself as they need to read the data from the same drive today) and b) on large memory systems they may agressively pre-fetch even for apps you haven't launched yet.

They have a second initiave to add flash caches to harddrives. It's possible that they are looking to augment that scheme here also with any flash memory device used as the cache. But since they say the device can be removed at ANY point, I don't think that is the case (otherwise you would REQUIRE a flush event from flash to the HD).

Bill