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How does Win allocate drive letters?


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Guest Stephen Ford
Posted

WinXP SP2 (up to date with Win Update)

 

I have a problem where a third party device when plugged into a USB port

becomes accessible via a drive letter it creates and the drive letter

conflicts with an existing drive letter.

 

My PC has one HDD in three partitions and there is a CD drive. So the drive

letters are C:, D:, E: & F:

 

I use the following batch file at start up

 

echo on

subst H: D:\

subst J: D:\data

subst K: "D:\DATA\Acquire Home Services"

subst L: D:\DATA\Paradox

subst M: "D:\DATA\WP9 App data"

subst N: "C:\Documents and Settings\Office\Application

Data\Corel\PerfectExpert\9\Custom WP Templates"

Pause

exit

 

When the device is plugged in it creates "Removable Disk (G:)" &

"TomTom(H:)". the H: conflicts with the H: drive created by the batch file.

Yes, it's a TomTom sat.nav.

 

My initial discussion with TomTom support resulted in the comment "it's

Windows that creates the drive and causes the conflict, not TomTom". I can

believe it's feasible but I wonder if there is such a hole in the O/S such

that it tramples over drives created by the SUBST command. What might be

going on?

 

--

Regards

Stephen Ford

  • Replies 15
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Guest vista terminal ator
Posted

Re: How does Win allocate drive letters?

 

you can change the letters of hdd and cdroms and external devices from

 

control panel, administrative tools, computer managment, disk managment.

 

right click on the one you want and give it another letter...

 

I suggest you change the letters of the conflicting devices to somthing like

m, n, o, p so you can leave letter-space for the removable device you add

later

"Stephen Ford" <stephen_ford_NO_@_SPAM_uwclub.net> wrote in message

news:ea7xcQ57HHA.1212@TK2MSFTNGP05.phx.gbl...

> WinXP SP2 (up to date with Win Update)

>

> I have a problem where a third party device when plugged into a USB port

> becomes accessible via a drive letter it creates and the drive letter

> conflicts with an existing drive letter.

>

> My PC has one HDD in three partitions and there is a CD drive. So the

> drive letters are C:, D:, E: & F:

>

> I use the following batch file at start up

>

> echo on

> subst H: D:\

> subst J: D:\data

> subst K: "D:\DATA\Acquire Home Services"

> subst L: D:\DATA\Paradox

> subst M: "D:\DATA\WP9 App data"

> subst N: "C:\Documents and Settings\Office\Application

> Data\Corel\PerfectExpert\9\Custom WP Templates"

> Pause

> exit

>

> When the device is plugged in it creates "Removable Disk (G:)" &

> "TomTom(H:)". the H: conflicts with the H: drive created by the batch

> file. Yes, it's a TomTom sat.nav.

>

> My initial discussion with TomTom support resulted in the comment "it's

> Windows that creates the drive and causes the conflict, not TomTom". I can

> believe it's feasible but I wonder if there is such a hole in the O/S such

> that it tramples over drives created by the SUBST command. What might be

> going on?

>

> --

> Regards

> Stephen Ford

>

>

Guest Stephen Ford
Posted

Re: How does Win allocate drive letters?

 

Thanks for that.

 

I've just discovered elsewhere that removeable drive letters created when a

removable device is connected can conflict with non-hardware drive letters

(eg as created by network systems or the SUBST command).

 

So as you say, I need to move my non-hardware drive letters further up the

alphabet to leave room for removable drive letters. It would be nice if

Windows coped with this automatically.

 

--

Regards

Stephen Ford

 

 

"vista terminal ator" <-> wrote in message

news:46de69be$1@newsgate.x-privat.org...

> you can change the letters of hdd and cdroms and external devices from

>

> control panel, administrative tools, computer managment, disk managment.

>

> right click on the one you want and give it another letter...

>

> I suggest you change the letters of the conflicting devices to somthing

> like m, n, o, p so you can leave letter-space for the removable device you

> add later

> "Stephen Ford" <stephen_ford_NO_@_SPAM_uwclub.net> wrote in message

> news:ea7xcQ57HHA.1212@TK2MSFTNGP05.phx.gbl...

>> WinXP SP2 (up to date with Win Update)

>>

>> I have a problem where a third party device when plugged into a USB port

>> becomes accessible via a drive letter it creates and the drive letter

>> conflicts with an existing drive letter.

>>

>> My PC has one HDD in three partitions and there is a CD drive. So the

>> drive letters are C:, D:, E: & F:

>>

>> I use the following batch file at start up

>>

>> echo on

>> subst H: D:\

>> subst J: D:\data

>> subst K: "D:\DATA\Acquire Home Services"

>> subst L: D:\DATA\Paradox

>> subst M: "D:\DATA\WP9 App data"

>> subst N: "C:\Documents and Settings\Office\Application

>> Data\Corel\PerfectExpert\9\Custom WP Templates"

>> Pause

>> exit

>>

>> When the device is plugged in it creates "Removable Disk (G:)" &

>> "TomTom(H:)". the H: conflicts with the H: drive created by the batch

>> file. Yes, it's a TomTom sat.nav.

>>

>> My initial discussion with TomTom support resulted in the comment "it's

>> Windows that creates the drive and causes the conflict, not TomTom". I

>> can believe it's feasible but I wonder if there is such a hole in the O/S

>> such that it tramples over drives created by the SUBST command. What

>> might be going on?

>>

>> --

>> Regards

>> Stephen Ford

>>

>>

>

>

Guest Uwe Sieber
Posted

Re: How does Win allocate drive letters?

 

 

It scans from C: upwards for the first availlable letter.

XP doesn't care about subst and net drive letters here.

Vista does but if you attach an USB drive for the first

time before your subst drives are created it may assing

a letter intended as subst drive, so the subst command

will fail later.

 

Either let some low letters unused for external drives

or install my tool 'USB drive letter manager'. Here

you can reserve you subst drive letters so they are

never used for othter drives.

http://www.uwe-sieber.de/usbdlm_e.html

 

You need an USBDLM.INI like this:

 

[ExcludedLetters]

Letter1=H

Letter2=J

Letter3=K

Letter4=L

Letter5=M

Letter6=N

 

Or define default letters for USB drives:

 

[DriveLetters]

Letter1=O

Letter2=P

Letter3=Q

Letter4=R

Letter5=S

Letter6=T

 

 

Greetings from Germany

 

Uwe

 

 

 

Stephen Ford wrote:

> WinXP SP2 (up to date with Win Update)

>

> I have a problem where a third party device when plugged into a USB port

> becomes accessible via a drive letter it creates and the drive letter

> conflicts with an existing drive letter.

>

> My PC has one HDD in three partitions and there is a CD drive. So the drive

> letters are C:, D:, E: & F:

>

> I use the following batch file at start up

>

> echo on

> subst H: D:\

> subst J: D:\data

> subst K: "D:\DATA\Acquire Home Services"

> subst L: D:\DATA\Paradox

> subst M: "D:\DATA\WP9 App data"

> subst N: "C:\Documents and Settings\Office\Application

> Data\Corel\PerfectExpert\9\Custom WP Templates"

> Pause

> exit

>

> When the device is plugged in it creates "Removable Disk (G:)" &

> "TomTom(H:)". the H: conflicts with the H: drive created by the batch file.

> Yes, it's a TomTom sat.nav.

>

> My initial discussion with TomTom support resulted in the comment "it's

> Windows that creates the drive and causes the conflict, not TomTom". I can

> believe it's feasible but I wonder if there is such a hole in the O/S such

> that it tramples over drives created by the SUBST command. What might be

> going on?

>

Guest Stephen Ford
Posted

Re: How does Win allocate drive letters?

 

Hi Uwe

 

A fantastic product! It might be small and simple (although I couldn't write

it) but it does the job; It does what you say it does and it has enabled me

to connect my TomTom without changing my list of drive letters on my PC.

Phew, thank goodness!

 

I'm amazed by the unhelpfulness of TomTom (not a small company!). They have

just replied to my support request by saying they can;'t help. They have not

even explained the problem with Windows and suggested a route (and do they

know about finding routes*!?) for me to take in my search for a solution.

 

My search this morning has resulted in finding your product (or did you find

me :-) ) and a number of other interested people. I am going to post your

details on the Expansis.com web site where I have had some help and I will

give all your details to TomTom.

 

I have purchased a licence.

 

Good luck with your other business ideas.

 

--

Regards

Stephen Ford, Cambeley, UK

Guest Stephen Ford
Posted

Re: How does Win allocate drive letters?

 

I hope you don't mind me helping with some words in your reply.

 

The word "assing" needs to be "assign" (typo I think...), and the word "let"

in "Either let some low letters .." needs to be "leave" ie "Either leave

some low letters .."

 

HTH

--

Regards

Stephen Ford

 

 

"Uwe Sieber" <mail@uwe-sieber.de> wrote in message

news:5k7c56F2fav6U2@mid.individual.net...

>

> It scans from C: upwards for the first availlable letter.

> XP doesn't care about subst and net drive letters here.

> Vista does but if you attach an USB drive for the first

> time before your subst drives are created it may assing

> a letter intended as subst drive, so the subst command

> will fail later.

>

> Either let some low letters unused for external drives

> or install my tool 'USB drive letter manager'. Here

> you can reserve you subst drive letters so they are

> never used for othter drives.

> http://www.uwe-sieber.de/usbdlm_e.html

>

> You need an USBDLM.INI like this:

>

> [ExcludedLetters]

> Letter1=H

> Letter2=J

> Letter3=K

> Letter4=L

> Letter5=M

> Letter6=N

>

> Or define default letters for USB drives:

>

> [DriveLetters]

> Letter1=O

> Letter2=P

> Letter3=Q

> Letter4=R

> Letter5=S

> Letter6=T

>

>

> Greetings from Germany

>

> Uwe

>

>

>

> Stephen Ford wrote:

>> WinXP SP2 (up to date with Win Update)

>>

>> I have a problem where a third party device when plugged into a USB port

>> becomes accessible via a drive letter it creates and the drive letter

>> conflicts with an existing drive letter.

>>

>> My PC has one HDD in three partitions and there is a CD drive. So the

>> drive letters are C:, D:, E: & F:

>>

>> I use the following batch file at start up

>>

>> echo on

>> subst H: D:\

>> subst J: D:\data

>> subst K: "D:\DATA\Acquire Home Services"

>> subst L: D:\DATA\Paradox

>> subst M: "D:\DATA\WP9 App data"

>> subst N: "C:\Documents and Settings\Office\Application

>> Data\Corel\PerfectExpert\9\Custom WP Templates"

>> Pause

>> exit

>>

>> When the device is plugged in it creates "Removable Disk (G:)" &

>> "TomTom(H:)". the H: conflicts with the H: drive created by the batch

>> file. Yes, it's a TomTom sat.nav.

>>

>> My initial discussion with TomTom support resulted in the comment "it's

>> Windows that creates the drive and causes the conflict, not TomTom". I

>> can believe it's feasible but I wonder if there is such a hole in the O/S

>> such that it tramples over drives created by the SUBST command. What

>> might be going on?

>>

Posted

Re: How does Win allocate drive letters?

 

Left to it's own, XP automatically assigns Local drive letters

(non-floppy) starting with C: and working up. Network drive letters will

be automaticaly assigned starting with Z: and working their way down. IF

someone starts assigning letters manually, then they take the

responsibility of sorting out the conflicts.

 

Stephen Ford wrote:

> WinXP SP2 (up to date with Win Update)

>

> I have a problem where a third party device when plugged into a USB port

> becomes accessible via a drive letter it creates and the drive letter

> conflicts with an existing drive letter.

>

> My PC has one HDD in three partitions and there is a CD drive. So the drive

> letters are C:, D:, E: & F:

>

> I use the following batch file at start up

>

> echo on

> subst H: D:\

> subst J: D:\data

> subst K: "D:\DATA\Acquire Home Services"

> subst L: D:\DATA\Paradox

> subst M: "D:\DATA\WP9 App data"

> subst N: "C:\Documents and Settings\Office\Application

> Data\Corel\PerfectExpert\9\Custom WP Templates"

> Pause

> exit

>

> When the device is plugged in it creates "Removable Disk (G:)" &

> "TomTom(H:)". the H: conflicts with the H: drive created by the batch file.

> Yes, it's a TomTom sat.nav.

>

> My initial discussion with TomTom support resulted in the comment "it's

> Windows that creates the drive and causes the conflict, not TomTom". I can

> believe it's feasible but I wonder if there is such a hole in the O/S such

> that it tramples over drives created by the SUBST command. What might be

> going on?

>

Guest Stephen Ford
Posted

Re: How does Win allocate drive letters?

 

I use the batch file to create a standard look and feel to my PCs. All s/w

is then configured the same. I don't know if there is a better way. It cause

this removable disc prob though. USBDLM seems to have solved that.

 

--

Regards

Stephen Ford

Guest Uwe Sieber
Posted

Re: How does Win allocate drive letters?

 

 

Thanks :-)

 

Stephen Ford wrote:

> I hope you don't mind me helping with some words in your reply.

>

> The word "assing" needs to be "assign" (typo I think...), and the word "let"

> in "Either let some low letters .." needs to be "leave" ie "Either leave

> some low letters .."

>

> HTH

Posted

Re: How does Win allocate drive letters?

 

Bob I wrote:

> Left to it's own, XP automatically assigns Local drive letters

> (non-floppy) starting with C: and working up. Network drive letters

> will be automaticaly assigned starting with Z: and working their way

> down. IF someone starts assigning letters manually, then they take the

> responsibility of sorting out the conflicts.

 

I'm curious though as to why the OS can't sort out these conflicts? I

realize it's a different mechanism for assigning a drive letter to a

physical hard drive than mapping a network share (or even using the subst

command), but you wouldn't think it'd be that hard for the OS to check if

that particular letter is in use. The OS has to know at some level that

it's in use or not.

Guest Stephen Ford
Posted

Re: How does Win allocate drive letters?

 

> I'm curious though as to why the OS can't sort out these conflicts? I

> realize it's a different mechanism for assigning a drive letter to a

> physical hard drive than mapping a network share (or even using the subst

> command), but you wouldn't think it'd be that hard for the OS to check if

> that particular letter is in use. The OS has to know at some level that

> it's in use or not.

 

Well exactly. I mean, MS have built and entire O/S - so they must know

something about this sort of issue. You say "I realize it's a different

mechanism for assigning a drive letter ..." - I don't have clue how this is

done - not my field at all, but in the end the process for look for drives

must be able to sense "a drive letter" whatever it's type (I mean isn't this

C++'s forte?) and if it exists then (surely) don't trample over it...

Guest Lil' Dave
Posted

Re: How does Win allocate drive letters?

 

"Stephen Ford" <stephen_ford_NO_@_SPAM_uwclub.net> wrote in message

news:ea7xcQ57HHA.1212@TK2MSFTNGP05.phx.gbl...

> WinXP SP2 (up to date with Win Update)

>

> I have a problem where a third party device when plugged into a USB port

> becomes accessible via a drive letter it creates and the drive letter

> conflicts with an existing drive letter.

>

> My PC has one HDD in three partitions and there is a CD drive. So the

> drive letters are C:, D:, E: & F:

>

> I use the following batch file at start up

>

> echo on

> subst H: D:\

> subst J: D:\data

> subst K: "D:\DATA\Acquire Home Services"

> subst L: D:\DATA\Paradox

> subst M: "D:\DATA\WP9 App data"

> subst N: "C:\Documents and Settings\Office\Application

> Data\Corel\PerfectExpert\9\Custom WP Templates"

> Pause

> exit

>

> When the device is plugged in it creates "Removable Disk (G:)" &

> "TomTom(H:)". the H: conflicts with the H: drive created by the batch

> file. Yes, it's a TomTom sat.nav.

>

> My initial discussion with TomTom support resulted in the comment "it's

> Windows that creates the drive and causes the conflict, not TomTom". I can

> believe it's feasible but I wonder if there is such a hole in the O/S such

> that it tramples over drives created by the SUBST command. What might be

> going on?

>

> --

> Regards

> Stephen Ford

>

>

 

My experience: XP assigns "drive" letters on first come/first serve basis

beginning at installation time. The former hierarchy that msdos had used is

no longer valid in XP. That's why as soon as the XP install is done, I

assign a letter like "S" or "T" to a CD or DVD device. Reassign any other

partition lettering as well at that time in accordance with the msdos drive

hierarchy as this is very familiar to me. The only thing I don't bother

myself with in my USB thumb drive that takes "W".

 

If I were to assign a folder a "drive" letter, I would do the same thing as

above. Then, assign subsequent letters to each folder.

Dave

Guest Paul Randall
Posted

Re: How does Win allocate drive letters?

 

Maybe each OS keeps doing the same wrong thing to maintain compatibility

with the previous OS. By now there could be millions of people relying on

this behavior.

 

-Paul Randall

 

"Stephen Ford" <stephen_ford_NO_@_SPAM_uwclub.net> wrote in message

news:%23Jo9ZJG8HHA.1184@TK2MSFTNGP04.phx.gbl...

>> I'm curious though as to why the OS can't sort out these conflicts? I

>> realize it's a different mechanism for assigning a drive letter to a

>> physical hard drive than mapping a network share (or even using the subst

>> command), but you wouldn't think it'd be that hard for the OS to check if

>> that particular letter is in use. The OS has to know at some level that

>> it's in use or not.

>

> Well exactly. I mean, MS have built and entire O/S - so they must know

> something about this sort of issue. You say "I realize it's a different

> mechanism for assigning a drive letter ..." - I don't have clue how this

> is done - not my field at all, but in the end the process for look for

> drives must be able to sense "a drive letter" whatever it's type (I mean

> isn't this C++'s forte?) and if it exists then (surely) don't trample over

> it...

>

Posted

Re: How does Win allocate drive letters?

 

> "Stephen Ford" <stephen_ford_NO_@_SPAM_uwclub.net> wrote in message

> news:%23Jo9ZJG8HHA.1184@TK2MSFTNGP04.phx.gbl...

>>> I'm curious though as to why the OS can't sort out these conflicts?

>>> I realize it's a different mechanism for assigning a drive letter

>>> to a physical hard drive than mapping a network share (or even

>>> using the subst command), but you wouldn't think it'd be that hard

>>> for the OS to check if that particular letter is in use. The OS

>>> has to know at some level that it's in use or not.

>>

>> Well exactly. I mean, MS have built and entire O/S - so they must

>> know something about this sort of issue. You say "I realize it's a

>> different mechanism for assigning a drive letter ..." - I don't have

>> clue how this is done - not my field at all, but in the end the

>> process for look for drives must be able to sense "a drive letter"

>> whatever it's type (I mean isn't this C++'s forte?) and if it exists

>> then (surely) don't trample over it...

>Paul Randall wrote:

> Maybe each OS keeps doing the same wrong thing to maintain

> compatibility with the previous OS. By now there could be millions

> of people relying on this behavior.

>

> -Paul Randall

 

I understand what you're saying and in some contexts it would make some

sense. However, in this case I don't quite understand how anyone could be

relying on this type of behavior? Why would anyone want Windows to take

over drive letter when it's already in use by you and/or the system.

Guest Paul Randall
Posted

Re: How does Win allocate drive letters?

 

 

"GO" <aa533@remove.this.chebucto.ns.ca> wrote in message

news:%23epDW%23O8HHA.3400@TK2MSFTNGP03.phx.gbl...

>

>> "Stephen Ford" <stephen_ford_NO_@_SPAM_uwclub.net> wrote in message

>> news:%23Jo9ZJG8HHA.1184@TK2MSFTNGP04.phx.gbl...

>>>> I'm curious though as to why the OS can't sort out these conflicts?

>>>> I realize it's a different mechanism for assigning a drive letter

>>>> to a physical hard drive than mapping a network share (or even

>>>> using the subst command), but you wouldn't think it'd be that hard

>>>> for the OS to check if that particular letter is in use. The OS

>>>> has to know at some level that it's in use or not.

>>>

>>> Well exactly. I mean, MS have built and entire O/S - so they must

>>> know something about this sort of issue. You say "I realize it's a

>>> different mechanism for assigning a drive letter ..." - I don't have

>>> clue how this is done - not my field at all, but in the end the

>>> process for look for drives must be able to sense "a drive letter"

>>> whatever it's type (I mean isn't this C++'s forte?) and if it exists

>>> then (surely) don't trample over it...

>

>>Paul Randall wrote:

>> Maybe each OS keeps doing the same wrong thing to maintain

>> compatibility with the previous OS. By now there could be millions

>> of people relying on this behavior.

>>

>> -Paul Randall

>

> I understand what you're saying and in some contexts it would make some

> sense. However, in this case I don't quite understand how anyone could be

> relying on this type of behavior? Why would anyone want Windows to take

> over drive letter when it's already in use by you and/or the system.

 

Your last sentence indicates you got the point of my backhanded statement.

How do nasty little things like this not get fixed generation after

generation? By accident? By not knowing the problem exists? By wanting it

not to get fixed?

 

-Paul Randall

Posted

Re: How does Win allocate drive letters?

 

Paul Randall wrote:

> "GO" <aa533@remove.this.chebucto.ns.ca> wrote in message

> news:%23epDW%23O8HHA.3400@TK2MSFTNGP03.phx.gbl...

>>

>>> "Stephen Ford" <stephen_ford_NO_@_SPAM_uwclub.net> wrote in message

>>> news:%23Jo9ZJG8HHA.1184@TK2MSFTNGP04.phx.gbl...

>>>>> I'm curious though as to why the OS can't sort out these

>>>>> conflicts? I realize it's a different mechanism for assigning a

>>>>> drive letter to a physical hard drive than mapping a network

>>>>> share (or even using the subst command), but you wouldn't think

>>>>> it'd be that hard for the OS to check if that particular letter

>>>>> is in use. The OS has to know at some level that it's in use or

>>>>> not.

>>>>

>>>> Well exactly. I mean, MS have built and entire O/S - so they must

>>>> know something about this sort of issue. You say "I realize it's a

>>>> different mechanism for assigning a drive letter ..." - I don't

>>>> have clue how this is done - not my field at all, but in the end

>>>> the process for look for drives must be able to sense "a drive

>>>> letter" whatever it's type (I mean isn't this C++'s forte?) and if

>>>> it exists then (surely) don't trample over it...

>>

>>> Paul Randall wrote:

>>> Maybe each OS keeps doing the same wrong thing to maintain

>>> compatibility with the previous OS. By now there could be millions

>>> of people relying on this behavior.

>>>

>>> -Paul Randall

>>

>> I understand what you're saying and in some contexts it would make

>> some sense. However, in this case I don't quite understand how

>> anyone could be relying on this type of behavior? Why would anyone

>> want Windows to take over drive letter when it's already in use by

>> you and/or the system.

>

> Your last sentence indicates you got the point of my backhanded

> statement. How do nasty little things like this not get fixed

> generation after generation? By accident? By not knowing the

> problem exists? By wanting it not to get fixed?

>

> -Paul Randall

 

Aaaah....sarcasm eh? Gotcha. My apologies. I thought you were being

serious....I'm getting too used to the flamewars going on over in the Vista

group. :)


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