2 drives what letter is on which drive

mrwebmaster
mrwebmaster used Ask the Experts™
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I am out of room on my c: drive
I have 2 drives and both have 2 partitions on each. for a total of drive letters
C: D: E: and F:

Does the first drive have C: and D: or C: and E:
I am told that with 2 drives with 2 partitions each, XP will skip a letter and have C: on the first and D: on the second.
 
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First drive will be labeled C & D and the Second Drive would be E & F

RIley

Commented:
"I am told that with 2 drives with 2 partitions each, XP will skip a letter and have C: on the first and D: on the second."

That statement would be partly true if you was running Win98
C= primary partition on first HD
D= primary on second HD
E= second partition on first HD
and if there was more then 2 partitions then they would be labeled in order.
F= second partition on second HD.
this would continue in order until all partitions had a "leter"
Ok with nearly everything drive letters can be changed so the best way to tell what drive has what letters assigned to it is to go to the control panel select administrative tools then computer management expand the storage Icon then Highlight disk management. It will lisk your Disks 0-1 0 being your primary and 1 being your secondary this will also show your partitions and what letter is assigned to each.

Hope this helps.

Dave
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Commented:
I go along with rayt333 in the numbering sequence of drives partitioned and formatted for windows98
cheers
Pete

Commented:
As usual, rayt333 is right about the default lettering sequence.

If you do add or subtract partitions, add or subtract drives, or change the assignment of letters, the installed programs (and shortcuts, of course) won't work any more.  Rather than manually reinstalling everything with the new drive letters (so the registry gets all the correct information), you can use Powerquest's Partition Magic utility, Drive Mapper.  It will update all the info on the system to match new drive letters.

You have to do the whole operation very carefully, though, and in the proper order.  For example, if you have your present configuration and added a third hard drive, C and D would remain the same, but the primary partition on the third hard drive would become E, then the second partition on the first hard drive (the old E) would become F and the second partition on the second hard drive (the old F) would become G.  If you were able to "map" all previous references to E and made them F, then "mapped" all references to F and made them G, you can see that you would have not only replaced the old F's with G, but you would have replaced all the "new" F's with G also, so your old E (new F) would be referenced incorrectly (there would be no references to F anywhere, since they'd all now be G).

You don't have to add a hard drive to have this problem, of course.  If you add a partition to your first hard drive, the following occurs:  C and D remain the same, but the second and third partitions on the first drive become E and F; the second partition on the second hard drive becomes G (it used to be F).

The instructions that come with the utility will help to make sure you do the operations in the correct order to keep this from being the mess it looks like the way I'm writing it here.  Actually, I guess it really is a mess, unless you clearly understand how drive lettering works.  Again, rayt333 has it right and jayriley25 does not.  To the best of my knowledge, the default lettering is no different between Win98 and WinXP.

Commented:
Actually there is difference between Win98 and XP, jayriley25's comment was correct for the default for XP, the drives are named by letters starting with all partitions on first HD then all partitions on second HD.
first HD
C
D
second HD
E
F

Commented:
Well, you learn something every day.  Sorry about the long post, then.  

Strangely enough, then on my system (WinXP Pro), the first drive has two partitions, the second and third drives have only one partition each.  Yet C, D, and E are the three primary partitions; F is the second partition on the first physical drive.  If XP did it differently then Win98, it seems that D would be the second partition on the first drive, my SCSI drive would be E, and the second IDE would be F....

Commented:
Well, you learn something every day.  Sorry about the long post, then.  

Strangely enough, then on my system (WinXP Pro), the first drive has two partitions, the second and third drives have only one partition each.  Yet C, D, and E are the three primary partitions; F is the second partition on the first physical drive.  If XP did it differently then Win98, it seems that D would be the second partition on the first drive, my SCSI drive would be E, and the second IDE would be F....

Commented:
rayt333:

Can't find a source for XP; however, this is what Microsoft says about drive letter assignment in Win2000 (and I thought XP did it the same):

The following are the basic disk drive letter assignment rules for Windows 2000:
-  Scan all fixed hard disks as they are enumerated, assign drive letters starting with any active primary partitions (if there is one), otherwise, scan the first primary partition on each drive. Assign next available letter starting with C:
-  Repeat scan for all fixed hard disks and removable (JAZ, MO) disks and assign drive letters to all logical drives in an extended partition, or the removable disk(s) as enumerated. Assign next available letter starting with C:.
-  Finally, repeat scan for all fixed hard disk drives, and assign drive letters to all remaining primary partitions. Assign next available letter starting with C:.
-  Floppy drives. Assign letter starting with A:
-  CD-ROM drives. Assign next available letter starting with D:.
=================================================
Do you know of a similar source for XP's assignment (if different)?

Commented:
Here is what I found on default drive letter assignment, but I have installed XP into 5 different computers and each of them defaulted to the order I mentioned above, first HD in order then second HD. I have one setup as dual boot with Win98 and Win98 sees them the old way but XP sees them in order.
Maybe something I did during the setup that caused it but I didn't do anything special as I remember.

Operating systems that use drive letter assignment:

    * CP/M
    * DOS
    * Windows 3.1
    * Windows 95/98/ME
    * Windows NT/2000/XP
* IBM OS/2

Each of these operating systems assign drive letters according to the following algorithm:

   1. Assign the drive letter 'A' to the boot floppy, and 'B' to the secondary floppy
   2. Assign a drive letter, beginning with 'C' to the first active primary partition recognized upon the first physical hard disk drive
   3. Assign subsequent drive letters to the first primary partition upon each successive physical hard disk drive, if present within the system.
   4. Assign subsequent drive letters to every recognized logical partition beginning with the first hard drive and proceeding through successive physical hard disk drives, if present within the system.

In the operating systems below, the assignment nominally follows the algorithm above, but can be manually changed by the system administrator:

    * Windows NT
    * Windows 2000
    * Windows XP
* OS/2

Commented:
Brain fart !!!!!!!!!!!!!!!!!!!!!!

Now I remember one important step I did take, only 3 of those computers had multi HD's and all of them have the extra HD in a removable caddy, and I do remember removing the caddy while installing XP, then after done with the installation I replaced the second HD and the letters fell into place after the CD-Rom's. My main computer looks like this:
A: floppy
C: first partition on first HD
D: second partition on first HD
E: third
F: fourth
G: fifth
H: sixth
J: CDR
K: CD-Rom
L: first partition second HD
M: second partition


I have each HD partitioned into 6 partitions and this is the way it defaulted to.
If you are using XP, just go into Control Panal,Admin Tools,Computer Manage,Disk Administrator you can see what drive letter is put on what, and you can change it also. But if you are on 98 then i agree with Rayt


Aren
Dave PuseyIT Support Specialist

Commented:
No comment has been added lately, so it's time to clean up this question.

I will leave the following recommendation in the Cleanup topic area:

Accept comment from mcmurrick

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Dave Pusey
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