"Write-aside" disk drives--do they exist?

  • Thread starter Thread starter Mxsmanic
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Mxsmanic

It has occurred to me that one could build a completely malware-proof
PC by installed special disk drives that do not actually accept write
operations, but instead write them aside into a temporary area that is
deallocated each time the drive is reset. Has anyone ever built such
a drive?

The idea is this: The drive has a complete OS and applications
installed. After the machine is booted, all physical writes directed
to the drive are in fact written into a cache memory (potentially a
reserved part of the disk). Whenever the disk drive is reset, the
cache is erased (all updated data is discarded), and the drive is back
where it began. Thus, no matter what happens while the PC is running,
the next time it is reset or booted, it comes up squeaky clean again.

The only way to disabled the write-aside would be through a hardware
switch that would be physically on the drive--one that could only be
flipped by hand, by a human being. This feature would be used to
initially install stuff on the disk and to make any subsequent
modifications.

So, has anyone done it? It would be great for Internet cafes in
particular.
 
Mxsmanic said:
It has occurred to me that one could build a completely malware-proof
PC by installed special disk drives that do not actually accept write
operations, but instead write them aside into a temporary area that is
deallocated each time the drive is reset. Has anyone ever built such
a drive?
Click to expand...
The idea is this: The drive has a complete OS and applications
installed. After the machine is booted, all physical writes directed
to the drive are in fact written into a cache memory (potentially a
reserved part of the disk). Whenever the disk drive is reset, the
cache is erased (all updated data is discarded), and the drive is back
where it began. Thus, no matter what happens while the PC is running,
the next time it is reset or booted, it comes up squeaky clean again.
Click to expand...
The only way to disabled the write-aside would be through a hardware
switch that would be physically on the drive--one that could only be
flipped by hand, by a human being. This feature would be used to
initially install stuff on the disk and to make any subsequent
modifications.

So, has anyone done it? It would be great for Internet cafes in
particular.
Click to expand...


Internet cafes often *do* use an arangement like this.
 
Mxsmanic said:
How does it work? You'd need actual hardware support to make it
secure.
Click to expand...

I use a system for my nephew taht allows me to restore with norton ghost
each week.Similar concept I guess
 
Mxsmanic said:
The idea is this: The drive has a complete OS and applications
installed. After the machine is booted, all physical writes directed
to the drive are in fact written into a cache memory (potentially a
reserved part of the disk). Whenever the disk drive is reset, the
cache is erased (all updated data is discarded), and the drive is back
where it began. Thus, no matter what happens while the PC is running,
the next time it is reset or booted, it comes up squeaky clean again.
Click to expand...

The same could be done with a RAMDisk, and it would also be faster.

You could also easily implement all writes to a disk (caches, temp files,
user files) by allocating a separate folder or logical drive for them. Have
the del *.* command for that folder/drive in a shutdown and/or startup batch
file.
 
Norton Ghost, or DiskImage2001 is virtually the same
thing. I use DiskImage, and I can restore an image
at 1.6 gig per minute. I keep a copy of the image on
my 160 gig USB drive. Also, I tend to update that
image as my system needs it .. if I trust the present
condition of the system files. For that reason, I
keep an older backup copy of the image in case
I discover a problem that I can't fix. I use this
technique to maintain stable operation of more
than 80 lab computers on my job. It works to
prevent vandalism and hacking, and minimize
downtime.

johns
 
johns said:
Norton Ghost, or DiskImage2001 is virtually the same
thing. I use DiskImage, and I can restore an image
at 1.6 gig per minute. I keep a copy of the image on
my 160 gig USB drive. Also, I tend to update that
image as my system needs it .. if I trust the present
condition of the system files. For that reason, I
keep an older backup copy of the image in case
I discover a problem that I can't fix. I use this
technique to maintain stable operation of more
than 80 lab computers
Click to expand...


Wow you doubled your computer pleasure in less than a month. Doesn't DELL
have ther own restore system?


on my job. It works to
 
Internet cafes often *do* use an arangement like this.
Click to expand...


Booting off any CD that has a run-from-CD setup will do what you want.
If the hard disk hs a partition marked as swap space it will increase
performacwe nicely and there will be security issues only if people
working for three-letter agencies are looking for your data.

I think you could use bartPE to do something like this for
Windows.

Windows 98 is nice for this as it's tiny and boots faster. I know a
huge internet Cafe (100+ machines) that are booted fresh for each use
from a server over 100mb ethernet. The disk is reimaged each time.
 
Mxsmanic said:
It has occurred to me that one could build a completely
malware-proof PC by installed special disk drives that do
not actually accept write operations, but instead write them
aside into a temporary area that is deallocated each time
the drive is reset. Has anyone ever built such a drive?
Click to expand...

Yes, most of the commercially packaged systems have a restore capability.
The idea is this: The drive has a complete OS and applications
installed. After the machine is booted, all physical writes directed
to the drive are in fact written into a cache memory (potentially a
reserved part of the disk). Whenever the disk drive is reset, the
cache is erased (all updated data is discarded), and the drive is back
where it began. Thus, no matter what happens while the PC is running,
the next time it is reset or booted, it comes up squeaky clean again.
Click to expand...

Makes more sense to use a standard hard drive and just
restore that as required. Completely trivial to automate.
The only way to disabled the write-aside would be through
a hardware switch that would be physically on the drive--
one that could only be flipped by hand, by a human being.
This feature would be used to initially install stuff on the
disk and to make any subsequent modifications.
Click to expand...
So, has anyone done it? It would be great for Internet cafes in particular.
Click to expand...

Yep, many cafes do that using a restore. That not only protects
against malware etc but protects the user's privacy etc as well.
 
Mxsmanic said:
It has occurred to me that one could build a completely malware-proof
PC by installed special disk drives that do not actually accept write
operations, but instead write them aside into a temporary area that is
deallocated each time the drive is reset. Has anyone ever built such
a drive?

The idea is this: The drive has a complete OS and applications
installed. After the machine is booted, all physical writes directed
to the drive are in fact written into a cache memory (potentially a
reserved part of the disk). Whenever the disk drive is reset, the
cache is erased (all updated data is discarded), and the drive is back
where it began. Thus, no matter what happens while the PC is running,
the next time it is reset or booted, it comes up squeaky clean again.

The only way to disabled the write-aside would be through a hardware
switch that would be physically on the drive--one that could only be
flipped by hand, by a human being. This feature would be used to
initially install stuff on the disk and to make any subsequent
modifications.

So, has anyone done it? It would be great for Internet cafes in
particular.
Click to expand...

I always like your posts. You have such interesting questions.

This has a little to do with your question. I'm reminded that this new
technology of "hybrid drives" or "ready drives" is coming soon!

http://en.wikipedia.org/wiki/Hybrid_drive

At the moment, the flash portion of the drive is slated for 1GB. That would
be more than enough for normal computing, and with the appropriate tweaking
you'd think you could get a very easy hardware based solution to the problem
of high-risk computing.

I'm anxious to see these things in operation.

~e.
 
Big said:
I use a system for my nephew taht allows me to restore with norton ghost
each week.Similar concept I guess
Click to expand...

But restoring with software raises the possibility of the software
being corrupted by malware. I suppose if you boot directly from a CD
you can get around this. Still, restoring is slower than just
declaring all cached writes invalid.
 
Rod said:
Makes more sense to use a standard hard drive and just
restore that as required. Completely trivial to automate.
Click to expand...

Restoring is much slower than invalidating a cache.
 
Mxsmanic said:
Big Brian writes
Click to expand...
But restoring with software raises the possibility of the
software being corrupted by malware. I suppose if you
boot directly from a CD you can get around this.
Click to expand...

Yep, completely eliminates any possibility of corruption.
Still, restoring is slower than just declaring all cached writes invalid.
Click to expand...

Yes, but thats no big deal if its scheduled for when the system isnt being used.

And has the big advantage of just using completely standard hardware.

I cant see your approach as being very viable,
most would want to at least keep their emails etc.
 
Mxsmanic said:
How does it work? You'd need actual hardware support to make it
secure.
Click to expand...

My ideas about this are somewhat vague, but it's not all down
with one machine. There is a master server that downloads
a clean environment to each user system when it is booted up.
Users are not allowed to run any software except what is pre-loaded
(including
software on removable media of course).
AFAIK, this is a variation of an arangmeent intended to allow users to
"hot desk"
with a downloaded profile that follows them around, except that
the persistence feature is swtiched off.
 
Mxsmanic said:
Rod Speed writes
Click to expand...
Restoring is much slower than invalidating a cache.
Click to expand...

Yes, but its completely trivial to automate so it happens
when you arent around so the time doesnt matter.

I cant see it being viable for other reasons, there must be few
who dont ever want to keep anything, particularly emails etc.

You should be able to get the result you want by using a ram drive.
 
Rod Speed said:
Yes, but its completely trivial to automate so it happens
when you arent around so the time doesnt matter.

I cant see it being viable for other reasons, there must be few
who dont ever want to keep anything, particularly emails etc.

You should be able to get the result you want by using a ram drive.
Click to expand...

It'd be pretty trivial to install knoppix on a write protected hard
drive. That way you'd have exactly what you want, everything
ends up in the ram drive and is gone when you reboot.
 
visions said:
I always like your posts. You have such interesting questions.
Click to expand...

Are you being serious or sarcastic?
This has a little to do with your question. I'm reminded that this new
technology of "hybrid drives" or "ready drives" is coming soon!

http://en.wikipedia.org/wiki/Hybrid_drive

At the moment, the flash portion of the drive is slated for 1GB. That would
be more than enough for normal computing, and with the appropriate tweaking
you'd think you could get a very easy hardware based solution to the problem
of high-risk computing.
Click to expand...

Perhaps so; certainly it would be more useful for that than for the
nominal purpose described in the article.

I have to confess that with respect to normal computing it appears to
be a solution looking for a problem. And Microsoft's involvement
makes me nervous: normally hardware features like this are transparent
to software, and if Microsoft is involved, that means that MS wants to
write code to manage something that should be transparent to the OS,
which means that the solution is not transparent (and is thus
error-prone) and that MS wants to use support for this type of
jury-rigged arrangement to motivate upgrades and maintain a revenue
stream. It's a bit like Intel using USB to sell hardware.
I'm anxious to see these things in operation.
Click to expand...

I think I'll pass. First, I don't need to worry about power or heat;
neither of them is significant on an ordinary desktop machine.
Second, starting and stopping a disk regularly does not improve
reliability at all. Nothing is more stressful to a drive than
starting and stopping, especially if it has flying heads (as most do).
This is even worse if the drives will be driven past spec speeds, as
the article implies. Third, flash memory has an asymmetric
access-time profile, as I recall, with writes requiring a lot more
time than reads. Fourth, flash memory can only be rewritten a finite
number of times. Fifth, starting the drive will introduce random,
long delays, and some software cannot tolerate this. (Besides, it's
already frustrating enough to have to wait ten seconds for an optical
drive to come up to speed.) None of this appeals to me.

I guess if it stays on laptops, I won't care, since I don't use
laptops, anyway.
 
Rod said:
I cant see your approach as being very viable,
most would want to at least keep their emails etc.
Click to expand...

You could keep some data on a server. Some e-mail systems and
protocols allow for the actual messages to be held on a server.
 
Rod said:
It'd be pretty trivial to install knoppix on a write protected hard
drive. That way you'd have exactly what you want, everything
ends up in the ram drive and is gone when you reboot.
Click to expand...

Do standard hard drives have a hardware switch for write protection?
I don't recall seeing anything like that, but I don't deal with drives
very often at that level.
 
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