Readyboost deletes cache on reboot

[Bob]

Just poking around under Vista's hood and it seems that Ready Boost deletes
it's cache and reforms it when a computer is rebooted. This appears to be
normal operation for Ready Boost..I had thought that once it sets up it's
cache that it would remain rather than rebuilding it on each boot as it
takes time to build it each time.
Bob

 

[Andy Pritchard]

Mine does this as well, why is this?

My computer is unusable for 5 minutes after start-up whilst it updates the
readyboost drive

Andy.

 

[Steve Thackery]

Really? I don't think mine is doing that. Tell me how you know it is
reformatting and reloading, and I'll check mine.

Thanks,

Steve

 

[Bob]

Really? I don't think mine is doing that. Tell me how you know it is
reformatting and reloading, and I'll check mine.

Thanks,

Steve

Go here:
Control Panel
System Maintenance
Performance Information and Tools
in the left pane, Advanced tools
View performance issues in event log
Microsoft/ReadyBoost /Operational

Click on the "Information" categories on the top left side and in the bottom
"General" tab it will say what operation was completed.
You will see an entry for the time at which you shutdown/rebooted that says
" A ReadyBoost cache was successfully deleted on the device (USB FLASH
DRIVE)

At your boot up time you will see an entry that reads:
"A ReadyBoost cache was successfully created on device (USB FLASH DRIVE) of
1960MB ( I'm using a 2GB flash drive so this size will vary depending on the
size of your flash drive)

Another thing I notice is this message:
"A defrag has completed. A boot plan will be calculated soon. Defrag
timestamp (UTC) :3/21/2007 5:36:03 PM "

So it appears to mean that the ReadyBoost cache is being defragged on it's
own ?
I have my computer set to defrag the hard drives once a month on the 1st so
I know this defrag is not controlled by my settings. Must be built in to
the ReadyBoost program?

Bob

 

[Richard Urban]

If the cache remained it would be a security hazard for corporations and
business'.

--


Regards,

Richard Urban MVP
Microsoft Windows Shell/User

 

[Bob]

If the cache remained it would be a security hazard for corporations and
business'.

--


Regards,

Richard Urban MVP
Microsoft Windows Shell/User

Makes sense...I thought that the data was encrypted to prevent that from
happening.
Good info to know.
Bob

 

[Steven Wimer]

I'm suprised an MVP would say that when Tom Archer's Blog says this:
http://blogs.msdn.com/tomarcher/archive/2006/06/02/615199.aspx

Q. Isn't user data on a removable device a security risk?

A: Everything that is written to the flash device is secured by ReadyBoost's
128-bit encryption, which means you don't have to worry about data security.

And Technet says:
http://www.microsoft.com/technet/technetmag/issues/2007/03/VistaKernel/

The driver encrypts each block it writes using Advanced Encryption Standard
(AES) encryption with a randomly generated per-boot session key in order to
guarantee the privacy of the data in the cache if the device is removed from
the system.

 

[Richard Urban]

Hey! We don't have the time to read everything. The fact remains that the
cache IS deleted when you shutdown/reboot. If you shutdown and boot up into
Windows XP the cache is no longer there. All the drives space is available
for Windows XP to use.

It either adds to the encryption, or is a "real" bug - not one of the
imaginary ones that the trolls write about.

--


Regards,

Richard Urban MVP
Microsoft Windows Shell/User

 

[Andy Pritchard]

I have had a look through the registry for any obvious settings like
doNotDeleteCache=0 but to no avail. As an MVP are you able to contact an
internal support team about the issue?


Andy.

 

[Steve Thackery]

Bob,

Mine is definitely not doing it. I've rebooted a couple of times, and all
it shows is 'Caching was enabled for device...', followed by another entry
entitled 'Summary of ReadyBoost performance'.

Steve

 

[Steve Thackery]

The fact remains that the cache IS deleted when you shutdown/reboot.

Only sometimes. See my post in reply to Bob above. Mine is definitely not
deleting the cache on shutdown/reboot.

This is obviously a bug affecting only some people.

Steve

 

[Andy Pritchard]

Just spotted the bit below:

"randomly generated per-boot session key"
http://www.microsoft.com/technet/technetmag/issues/2007/03/VistaKernel/

So what we need then is a doNotEncrypt option for home users

Andy.

 

[Bob]

Bob,

Mine is definitely not doing it. I've rebooted a couple of times, and all
it shows is 'Caching was enabled for device...', followed by another entry
entitled 'Summary of ReadyBoost performance'.

Steve

The first thing that tipped me off was seeing the date and time on .sfcache
file that gets created on the USB drive, after a reboot. I had previously
looked at the file date and it was dated from 2 days before ( last time I
had rebooted the machine). After a reboot I checked the file date and it was
the time of the reboot, so I dug a little deeper into Vista's tools and
found the delete and recreate entries. I also notice that on boot up the
flash drive's led flashes for 3 or 4 minutes, as I now know the new cache is
being created ( and populated?). I'll be watching to see if it's a bug to be
fixed or maybe some setting that needs to be changed somewhere.
Bob

 

[Victek]

That may be, but if ReadyBoost actually degrades performance instead of
improving it what's the point?

 

[Steve Thackery]

As stated above, the degradation only occurs on some people's machines, and
looks very much like a bug.

Thack

 

[cquirke (MVP Windows shell/user)]

On Sat, 24 Mar 2007 01:42:50 -0000, "Steve Thackery"

As stated above, the degradation only occurs on some people's machines, and
looks very much like a bug.

The Vista team were aware that the benefits of ReadyBoost would be a
trade-off that depends on whether the USB flash drive is fast and
large enough to make it worthwhile.

That's why Vista will test such drives, and refuse to enable
Readiboost of the drive is "too slow".

So the next thing we see, are hacks to force Vista to do Readiboost on
slow USB flash drives.

If, OTOH, you're using a drive that Vista doesn'thave to be hacked to
use, and it's still slower than without it, then there's either a bug,
or Vista's estimation of the break-even point was off, or there's
something particular to your system and the way you use it that is at
odds with the assumptions made by the Vista team in their assessment.

It will certainly delete the cache on reboot, else could be open to
exploits that pre-seed the contents between sessions.

-------------------- ----- ---- --- -- - - - -

Tip Of The Day:
To disable the 'Tip of the Day' feature...

 

[Guest]

The service crashed perhaps.

That all makes sense, but how do we explain the instances where the
readyboost cache is NOT deleted between reboots? I'm observing that it IS
deleted on my system, but some people say it's persistent.

 

[Victek]

On Sat, 24 Mar 2007 01:42:50 -0000, "Steve Thackery"


The Vista team were aware that the benefits of ReadyBoost would be a
trade-off that depends on whether the USB flash drive is fast and
large enough to make it worthwhile.

That's why Vista will test such drives, and refuse to enable
Readiboost of the drive is "too slow".

So the next thing we see, are hacks to force Vista to do Readiboost on
slow USB flash drives.

If, OTOH, you're using a drive that Vista doesn'thave to be hacked to
use, and it's still slower than without it, then there's either a bug,
or Vista's estimation of the break-even point was off, or there's
something particular to your system and the way you use it that is at
odds with the assumptions made by the Vista team in their assessment.

It will certainly delete the cache on reboot, else could be open to
exploits that pre-seed the contents between sessions.

That all makes sense, but how do we explain the instances where the
readyboost cache is NOT deleted between reboots? I'm observing that it IS
deleted on my system, but some people say it's persistent.

 

[Andy Pritchard]

It's not crashing because on shutdown in the event log it says:

"A ReadyBoost cache was successfully deleted on the device (Kingston
DataTraveler R)."

Andy.

 

[Bob]

So... do we know if it's supposed to be deleted on shutdown or not ? What do
the people who developed the program say..?
Bob