Hard disc recognition

[Andrew Borland]

I have a pair of caddy-mounted IDE hard discs which I use in rotation
for backup purposes. Each time I swap them over (cold swap), Windows
XP allocates a new drive letter and I have to rummage around in disc
management to reset it to the value expected by my backup routines.

What characteristic of the disc is Windows using to recognise that it
has changed? Is it the Volume ID, Volume Serial Number, or even some
invisible hardware serial number?

I would like to be able to be able to make these two discs appear
identical such that the caddy always get the same drive letter.

Alternatively, I'll settle for definitive proof that it can't be done!

Regards, Andrew Borland (UK)

 

[Guest]

The technique used in this utility may help:
http://www.uwe-sieber.de/usbdlm_e.html

Regards,
--PA

 

[Anna]

The technique used in this utility may help:
http://www.uwe-sieber.de/usbdlm_e.html

Regards,
--PA

Andrew:
I'm assuming that you're working with removable HDDs in their mobile racks,
not USB devices. That's right, isn't it?

1. These are PATA, not SATA drives, yes?

2. Assuming they are, are you dealing with two racks, or just one? If two
racks are involved, how are they configured with respect to their
connections to the IDE channels? I assume one is connected as Primary
Master, right? How is the second rack connected?

3. Are both drives identical - one being the clone of the other? Or are you
working with different operating systems in each HDD? What exactly do you
mean when you say "I use (them) in rotation for backup purposes".
Anna

 

[Andrew Borland]

Anna,

I'm assuming that you're working with removable HDDs in their mobile racks,
not USB devices. That's right, isn't it?

I think we may be using slightly different terminology here but you are
correct that I am using removable HDDs. I have one chasis (or rack) in the PC
tower case, and two discs, each in its own caddy (or tray). The rack is on
the Primary IDE cable as a slave.

(Having said that, I'll buy a couple of external enclosures and swap the
entire scheme to USB if that is going to make my life any easier).

1. These are PATA, not SATA drives, yes?

Yup. Parallel ATA drives on 80-way ribbon cables.

2. Assuming they are, are you dealing with two racks, or just one? If two
racks are involved, how are they configured with respect to their
connections to the IDE channels? I assume one is connected as Primary
Master, right? How is the second rack connected?

There is just one slot in the front of the PC case. This is what I think you
refer to as a rack and I know as the chasis. Into this one slot I insert one
of two caddies (or trays).

Disk connection/configuration is as follows:

IDE Primary Master is my fixed Boot drive (C:\)
IDE Primary Slave is the Rack for the removable drive (Normally Q:\)
IDE Secondary Master is DVD Drive (R:\)
IDE Secondary Slave is empty
There's a RAID controller providing my data partitions (D:\, E:\, F:\, G:\)
And finally a SCSI card for my faithful old Plexter CD-Rom (T:\)
USB sticks, card readers, etc occupy H:\ onwards.

3. Are both drives identical - one being the clone of the other? Or are you
working with different operating systems in each HDD? What exactly do you
mean when you say "I use (them) in rotation for backup purposes".

I'm not quite sure what you mean by clones. Both disks are Maxtor 6L250R0
units, both are used exclusively with this one Windows XP machine, but no
"disk imaging" software is involved. At any given instant, the data on the
two disks will be largely different.

By rotation I mean the following: On Sunday evening I put caddy number one in
the chasis, delete all the files on it and then copy the entirety of my fixed
disks to the caddy overnight. During the week I can make incremental updates
to the caddy (obviously much quicker). Next Sunday I'll do a final
incremental backup to caddy number one, then I remove caddy number one, insert
caddy number two, go through the palaver of reassigning it to Q:\ and then
repeat the sequence as above. In other words I've always got the previous
backup to fall back on if the current disk fails in mid operation. (This is a
trimmed down version of the triplicated approach I was taught to use with
Travan Tapes which were so unreliable I often needed that double fall-back).

Regards, Andrew Borland (UK)

 

[Andrew Borland]

The technique used in this utility may help:
http://www.uwe-sieber.de/usbdlm_e.html

Interesting. I'm not sure I can apply it to removable hard drives, but
it does hold out the prospect of an alternative USB based approach.

Regards, Andrew Borland (UK)

 

[Anna]

(Andrew's original posting...)

Anna,


I think we may be using slightly different terminology here but you are
correct that I am using removable HDDs. I have one chasis (or rack) in
the PC
tower case, and two discs, each in its own caddy (or tray). The rack is
on
the Primary IDE cable as a slave.

(Having said that, I'll buy a couple of external enclosures and swap the
entire scheme to USB if that is going to make my life any easier).


Yup. Parallel ATA drives on 80-way ribbon cables.


There is just one slot in the front of the PC case. This is what I think
you
refer to as a rack and I know as the chasis. Into this one slot I insert
one
of two caddies (or trays).

Disk connection/configuration is as follows:

IDE Primary Master is my fixed Boot drive (C:\)
IDE Primary Slave is the Rack for the removable drive (Normally Q:\)
IDE Secondary Master is DVD Drive (R:\)
IDE Secondary Slave is empty
There's a RAID controller providing my data partitions (D:\, E:\, F:\,
G:\)
And finally a SCSI card for my faithful old Plexter CD-Rom (T:\)
USB sticks, card readers, etc occupy H:\ onwards.


I'm not quite sure what you mean by clones. Both disks are Maxtor 6L250R0
units, both are used exclusively with this one Windows XP machine, but no
"disk imaging" software is involved. At any given instant, the data on
the
two disks will be largely different.

By rotation I mean the following: On Sunday evening I put caddy number
one in
the chasis, delete all the files on it and then copy the entirety of my
fixed
disks to the caddy overnight. During the week I can make incremental
updates
to the caddy (obviously much quicker). Next Sunday I'll do a final
incremental backup to caddy number one, then I remove caddy number one,
insert
caddy number two, go through the palaver of reassigning it to Q:\ and then
repeat the sequence as above. In other words I've always got the previous
backup to fall back on if the current disk fails in mid operation. (This
is a
trimmed down version of the triplicated approach I was taught to use with
Travan Tapes which were so unreliable I often needed that double
fall-back).

Regards, Andrew Borland (UK)

Andrew:
If I correctly understand your basic objective it is to have a backup copy
of your day-to-day working HDD that you can use for recovery/restore
purposes should that HDD fail or for one reason or another become unbootable
and dysfunctional. When all is said & done, that's what we're about, right?

If that be so...

Would it not be practical for you to simply employ a disk imaging program
such as Acronis True Image and routinely clone the contents of your (fixed,
internal) day-to-day working HDD to your removable HDD? Would that not meet
your objective in a reasonably simple, straightforward, and effective way?

In so creating this "clone", the recipient HDD (your removable HDD) would,
in effect, be a duplicate of your day-to-day working HDD and be instantly
bootable. It would have the same drive letter assignments of the source disk
that has been cloned. Using a disk imaging program, in lieu of the
disk-to-disk cloning operation, you could also consider creating a disk
image of your day-to-day working HDD (in effect, a file that is a "snapshot"
of the source disk) and use that disk image for purposes of restoration if &
when the need arises.

I'm not entirely clear on your need for two removable HDDs in your present
hardware configuration although it's obvious you can use that second
removable HDD for other purposes, e.g., different OS, additional storage,
etc.
Anna

 

[WillofAustralia]

I use a 2nd internal HDD just for the same purpose as you , and cannot find
a better way of backup than using Norton Ghost {Ver9} to backup on a daily
basis < backing up to the same folder on my slave disk {overwriting all data
per day} or you could have a different folder for each day, depending on
your HDD capacity

 

[Andrew Borland]

From: "Anna" <[email protected]>
Subject: Re: Hard disc recognition
Date: Tue, 6 Mar 2007 18:18:22 -0500
Newsgroups: microsoft.public.windowsxp.hardware


(Andrew's original posting...)





Andrew:
If I correctly understand your basic objective it is to have a backup copy
of your day-to-day working HDD that you can use for recovery/restore
purposes should that HDD fail or for one reason or another become unbootable
and dysfunctional. When all is said & done, that's what we're about, right?

If that be so...

Would it not be practical for you to simply employ a disk imaging program
such as Acronis True Image and routinely clone the contents of your (fixed,
internal) day-to-day working HDD to your removable HDD? Would that not meet
your objective in a reasonably simple, straightforward, and effective way?

In so creating this "clone", the recipient HDD (your removable HDD) would,
in effect, be a duplicate of your day-to-day working HDD and be instantly
bootable. It would have the same drive letter assignments of the source disk
that has been cloned. Using a disk imaging program, in lieu of the
disk-to-disk cloning operation, you could also consider creating a disk
image of your day-to-day working HDD (in effect, a file that is a "snapshot"
of the source disk) and use that disk image for purposes of restoration if &
when the need arises.

I'm not entirely clear on your need for two removable HDDs in your present
hardware configuration although it's obvious you can use that second
removable HDD for other purposes, e.g., different OS, additional storage,
etc.
Anna

Thanks Anna,

Down the years I have used various different drive imaging tools (PowerQuest
Drive Image (until it was brought out by Symantec), Paragon Drive Backup and
Acronis True Image) and they are all good tools, but none of them currently
provide quite what I'm looking for.

They would still leave me with the problem of the wandering drive letter each
time I swapped the hard disks over.

The reason for having the two removable disks is simple paranoia. I do backups
to protect against failure of the fixed disk, I rotate removable drives as
protection against failure of the removable drive. It also means I don't
delete one backup until after the next is complete. The same would still apply
if I was using imaging software.

"I'm not paranoid, they are out to get me".

Regards, Andrew Borland (UK)

 

[Andrew Borland]

As I noted to Anna, I have used and, in some other cases, still do use
disk imaging software but it doesn't quite fit the bill on the current
system.

I would also _never_ overwrite my most recent backup because, as sure
as eggs is eggs, that's the day when the hardware will fail half way
through.

Regards, Andrew Borland (UK)

 

[Anna]

As I noted to Anna, I have used and, in some other cases, still do use
disk imaging software but it doesn't quite fit the bill on the current
system.

I would also _never_ overwrite my most recent backup because, as sure
as eggs is eggs, that's the day when the hardware will fail half way
through.

Regards, Andrew Borland (UK)

Andrew:
All I can tell you is that based upon our experience of using a number of
different disk imaging programs over the years (we currently work mainly
with the Acronis True Image program in an XP environment) we've probably
carried out disk-to-disk cloning and/or disk imaging operations thousands of
times involving a multitude of different systems and by & large we've found
these programs to be reliable and effective. Not to say that issues/problems
don't arise from time to time (after all we're dealing with PCs here,
right?).

Having said this, we have a saying here in the colonies to the effect that
"Yer pays yer money and yer makes yer cherce".
Anna

 

[Andrew Borland]

Having said this, we have a saying here in the colonies to the effect that

According to my reading of the global economic climate, I think that _we_
are now the colony!

Regards, Andrew Borland (UK)

 

[Andy]

Go to <http://www.goodells.net/multiboot/partsigs.htm>, and read the
section "How does Windows XP remember drive letters?"
In order for Windows to think it's looking at the same disk, both
disks have to have the same disk signature in the MBR (see
<http://mirror.href.com/thestarman/asm/mbr/Win2kmbr.htm>), and the
partition(s) on the disks has to start at the same location(s).

 

[Andrew Borland]

Thanks Andy,

I spent most of last weekend Googling without finding either of those two
pages which, between them, appear to explain _everything_ I need to know
in this connection. It'll probably take me most of this weekend to fully
understand what they're trying to tell me.

Regards, Andrew Borland (UK)

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