Jonathon Jongsma wrote:
> 
> On 2/12/07, Erik Anderson <erikerik at gmail.com> wrote:
> > On 2/12/07, Jonathon Jongsma <jonathon.jongsma at gmail.com> wrote:
> > >
> > > Note that this flash-drive-as-swap is supposedly one of the new
> > > features of Windows Vista.  This is from the FAQ [1]:
> > > Q: Won't this wear out the drive?
> > > A: Nope. We're aware of the lifecycle issues with flash drives and are
> > > smart about how and when we do our writes to the device. Our research
> > > shows that we will get at least 10+ years out of flash devices that we
> > > support.
> > >
> > > I have no idea how long a device would last with a similar setup under linux...
> > >
> > > [1] http://blogs.msdn.com/tomarcher/archive/2006/06/02/615199.aspx
> >
> > This is really immaterial.  They're assuming that the flash device
> > will be used as flash devices normally are - as portable data transfer
> > media, not as swap.  It really doesn't matter which OS the device is
> > used with...rather, it's *how* the device is used.
> 
> Huh?  did you read the article?  It was *all* about using the flash
> drive as swap.
> 

Well, given the way the blog article referenced starts out, we can safely
ignore any conclusions about performance it draws.

	> Back in April, I posted a blog entry on the ReadyBoost
	> feature - the Windows Vista feature that allows you
	> to use a USB key as virtual memory in order to enhance
	> performance.

Using virtual memory of any kind never enhances performance.  It does
allow you to run larger and/or more applications at the same time.

Based on what I've seen scanning WWW sites about flash drives, most are
only good for about a million write cycles... no more.  Further, the top
rated speeds aren't achieved until reading > 64 KB or writing > 2048 KB,
which depending on how your box uses swap space, may be the wrong sizes
for good swap performance.

If you check out http://en.wikipedia.org/wiki/List_of_device_bandwidths,
you'll find a table of various bus-speeds.  Note that the maximum bus
speed can limit the maximum device speed when devices are faster than
the bus.  There are dozens of other disclaimers about observed versus
theoretical maximum rates of transfer, but in general, the faster a bus
is rated, the faster it will be in practice.

When visiting that page, compare USB "Hi-speed" against whatever kind
of disks you have in your computer.  Most modern disks operate at faster
bus speeds than the fastest available USB.

Which, in the end, means that if you want to slow your computer down,
substitute a USB flash drive for your current disk-resident swap space
(or, for that matter, any other kind of filesystem).

Just because you can doesn't mean you should.

Hope this helps,

-S