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

  • Thread starter Thread starter Mxsmanic
  • Start date Start date
Mxsmanic said:
Rod Speed writes
Click to expand...
Do standard hard drives have a hardware switch for write protection?
Click to expand...

Nope, but it isnt hard to do with a modified ribbon cable.
I don't recall seeing anything like that, but
I don't deal with drives very often at that level.
Click to expand...

Some scsi drives did, havent bothered with those for years tho.
 
Mxsmanic said:
Are you being serious or sarcastic?
Click to expand...

LOL! I'm being serious. Without stuff like this, these groups are boring.
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.
Click to expand...

Yeah. The ideal thing would to have the software showing how the flash
portion of the drive is interacting with its traditional portion. I'm
guessing that code is going to be very proprietary for a while. Like, these
will be drives with only a few manufacturers. It seems like it would be a
difficult thing to juggle just (like you said) for the variations in timing
involved. They say the things work, but I'm guessing the claims are a bit
exaggerated too.
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.
Click to expand...

Yeah. Me neither.

I don't know about the starting and stopping. I mean a scrap space of a Gig
seems to mean the drive would hardly start at all. I don't know. I'm
curious to see the final result. It makes me wonder if you couldn't adapt a
flashcard in a flashcard reader for the exact same purpose.

But yeah, it seems custom made for laptops which means I'll probably never
actually own one.

Cheers!

~e.
 
visions said:
I don't know about the starting and stopping. I mean a scrap space of a Gig
seems to mean the drive would hardly start at all.
Click to expand...

What about the paging file?
I don't know. I'm
curious to see the final result. It makes me wonder if you couldn't adapt a
flashcard in a flashcard reader for the exact same purpose.
Click to expand...

Flash cards seem to operate very slowly compared to disk drives,
especially when being written.
But yeah, it seems custom made for laptops which means I'll probably never
actually own one.
Click to expand...

I hope it will remain limited to laptops.
 
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.
Click to expand...

The problem is, part of what gives modern OS their
desirability is that they allow customization (even in minor
ways) that will need be remembered, not discarded, unless
the box is nothing more than a public kiosk where the
priority is a static interface for many different users.
The only way to disabled the write-aside would be through a hardware
switch that would be physically on the drive
Click to expand...

Why?

It's not as though you'd deploy a HDD image like this and
not have a backup of it, and since there are no user changes
possible,it's not even a big deal to restore such backup,
there is nothing that would've been lost- so the need to
make it 100% secure may be gone.

--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...

Quite a few things write to disk. I think more than you
realize.

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

The real question is what your exact goals are, not whether
a specific thing with a HDD is possible.

BIOS or a drive might be set for read-only, but what is a
reasonable prevention and what is foolproof, are different
things. Nothing is really foolproof, in the end some joker
will come along and take a sledgehammer or a box or just
kick it hard.

If all you want to do is redirect writes to cache memory,
take a look at EWF,
http://msdn.microsoft.com/library/d...ry/en-us/xpehelp/html/xerefewfdefinitions.asp

it is meant for XPe, Embedded, and suggested for removable
drive/device such as CDROM or flash memory based drive, but
that doesn't preclude use w/HDD, and a few have hacked it
into a regular XP too (middle of page),
http://www.windowsdevcenter.com/pub/a/windows/excerpt/CarPCHacks_Chap1/index.html?page=2

Then again, for those internet cafes it might be as well to
use XPe.
 
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.
Click to expand...


A CD disk is write-protected.
 
kony said:
The problem is, part of what gives modern OS their
desirability is that they allow customization (even in minor
ways) that will need be remembered, not discarded, unless
the box is nothing more than a public kiosk where the
priority is a static interface for many different users.
Click to expand...

I was thinking mainly of a public kiosk or hot-desk configuration,
although the same principle could be applied to some other systems if
their use is sufficiently generic.
Why?
Click to expand...

Because allowing anything to be done in software makes it vulnerable
to malware. If the switch is inaccessible to software, no virus or
trojan, no matter how clever, will be able to get around it.
If all you want to do is redirect writes to cache memory,
take a look at EWF,
http://msdn.microsoft.com/library/d...ry/en-us/xpehelp/html/xerefewfdefinitions.asp

it is meant for XPe, Embedded, and suggested for removable
drive/device such as CDROM or flash memory based drive, but
that doesn't preclude use w/HDD, and a few have hacked it
into a regular XP too (middle of page),
http://www.windowsdevcenter.com/pub/a/windows/excerpt/CarPCHacks_Chap1/index.html?page=2

Then again, for those internet cafes it might be as well to
use XPe.
Click to expand...

Nothing implemented in software would be secure.
 
kony writes:



I was thinking mainly of a public kiosk or hot-desk configuration,
although the same principle could be applied to some other systems if
their use is sufficiently generic.



Because allowing anything to be done in software makes it vulnerable
to malware. If the switch is inaccessible to software, no virus or
trojan, no matter how clever, will be able to get around it.



Nothing implemented in software would be secure.
Click to expand...
This concept doesn't have meaning to this home user. My experience with
computers goes back to 386 SX machines. In all that time I have never
been infected by virus or effected by malware. One time a friend gave
me a floppy to view. My anti virus flagged a Michaelangelo virus. But
it never got into the system. It was killed in the A: drive.

Unless you are a librarian or someone who has a lot of people using your
machines this paradigm is limited in application. For every black box
that is built someone will come along with the means to get into that
black box. They will do it if for no other reason than the challenge of
breaking that black box.

--
________
To email me, Edit "blog" from my email address.
Brian M. Kochera
"Some mistakes are too much fun to only make once!"
View My Web Page: http://home.earthlink.net/~brian1951
 
I was thinking mainly of a public kiosk or hot-desk configuration,
although the same principle could be applied to some other systems if
their use is sufficiently generic.


Because allowing anything to be done in software makes it vulnerable
to malware. If the switch is inaccessible to software, no virus or
trojan, no matter how clever, will be able to get around it.


Nothing implemented in software would be secure.
Click to expand...


If you are doing it to hardware sitting in front of a human,
what makes that secure, particularly when not that person's
property?

Nothing is "really" secure, just be glad there aren't more
crackers out there looking to flash your bios... there
aren't so many unique bios these days, and blocking HDD
write wouldn't prevent that.

If the real interest here is an internet cafe, why not just
ask one or two what they recommend?
 
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.
Click to expand...


Depends on your definition of "easily".
yes you can specify the ramdrive for many things, but to get
ALL of them (which write to HDD) is not same thing, not
necessarily easy and possibly time consuming if possible.
That is, unless you can accept that some things meant to be
written were lost, that it might impair functionality in
some cases.

For example, registry, several system or function-related
logs, error dumps, any apps that don't give an option on
where they write. Far too many windows-oriented things make
a basic presumption that you don't care how/where they work,
and that you don't care if they're incessantly writing to a
hard drive.
 
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.
Click to expand...
I didn't catch the entire message thread, so this may not be what you
are looking for. In case it can be of any help, I'll pass it along. I
recall reading that Microsoft has software to restore a computer back
to it's original status each day. I believe it's free.

Microsoft Shared Computer Toolkit for Windows XP

http://www.microsoft.com/windowsxp/sharedaccess/default.mspx
 
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