Switch the +5V supply to disk drive

[Vanguard]

in message

If the user is booting the other drive, no the other drive
becomes the "first" hard drive, unless using a boot menu off
the original drive, but honestly have you seen any boot
sector viri recently?

That wasn't my primary concern. Booting off the other drive but with
*all* drives powered on means the pests that are worried about on the
regular drive are still there and just as virulent to screw up the
secure drive. The expectation (but more like hope) is that user doesn't
run any programs from that regular drive -- but then the user is the one
that got that malware there in the first place. Expecting the user not
to run the infected files on the regular drive while the secure drive is
also powered up is just hoping the inevitable doesn't occur which has
already occurred.

No.

It will work just as I'd stated it, or to turn off the
alternate drive completely if that were desired so only one
is running at a time.

Wrong - but as you stated before in your other post. If *all* drives
are powered, it doesn't matter from which one the OS got loaded.
Executables on one drive are just as executable regardless of which
instance of the same OS got loaded from whatever drive. Only if the
regular drive is unpowered when the secure drive is powered can it be
guaranteed that the regular drive can't infect the secure drive - as you
now state. Problem is the same user is involved under any powerup
scenario.

I think we might actually be agreeing.

Secure drive powered
Regular drive powered
Pests on regular drive can infect the secure drive. Doesn't matter from
which drive the OS got loaded.

Secure drive unpowered
Regular drive powered
Pests on regular drive cannot do anything on the unpowered secure drive.
Secure drive is safe.

Secure drive powered
Regular drive unpowered
User can't run pests on regular drive because it is unpowered, so secure
drive is safe.

Only when the secure and regular drives are in opposite power states is
the secure drive safe from any pests on the regular drive. However, if
pests are showing up on the regular drive, they will show up on the
secure drive. Why not also do the same for the regular drive for
whatever supposedly made the secure drive more secure?

While the DPDT switch and its wiring harness is doable, I don't see it
as a better solution than using removable hard drives. The removed
"secure" drive won't be subject to the same shocks, surges, or other
physical damage while it is out of the host. Also remember that we have
yet to address the static that can be transferred through the switch
into the power leads for the hard drives. The toggle arm or rocker for
the switch would have to be electrically insulated from the contacts
cage getting moved inside the switch. An ordinary DPDT would transfer
the static discharge into the hard drives. With removable drives, the
user isn't touching the power or data lines.

 

[kony]

That wasn't my primary concern. Booting off the other drive but with
*all* drives powered on means the pests that are worried about on the
regular drive are still there and just as virulent to screw up the
secure drive. The expectation (but more like hope) is that user doesn't
run any programs from that regular drive -- but then the user is the one
that got that malware there in the first place.

Sure, but that's part of why I mentioned the issue - so it
was out there as something to be aware of.

Expecting the user not
to run the infected files on the regular drive while the secure drive is
also powered up is just hoping the inevitable doesn't occur which has
already occurred.

Seems pretty simple to me - now the OP knows that to prevent
that risk, nothing on the drive should be ran, opened, etc,
that has any risk of containing hostile code.

 

[Vanguard]

Wouldn't it be much simpler to just mount a Linux distribution?

<grins>

Only if the critical applications support that platform. Only boobs
pick an OS and then go hunting for their critical apps. We don't know
what applications are required by the OP for "financial transactions".
Could be browsing, might not. Could be a vertial market app that only
runs on Windows.