Archived from groups: alt.sys.pc-clone.dell (
More info?)
On Sat, 17 Apr 2004 04:55:18 GMT, in alt.sys.pc-clone.dell, "Thomas G.
Marshall" <tgm2tothe10thpower@replacetextwithnumber.hotmail.com> wrote:
>Are you sure that it wasn't the practice of assigning drive letters to
>primary partitions on all drives (hard or cd or whatever) before assigning
>letters elsewhere?
>
>I seem to always notice that (assuming only 1 partition per drive) the
>primary/master was always C: no matter what. And if something was on the
>secondary/master (no matter what it was) it became d:
Yes, I'm quite sure.
CD-ROM drives were assigned drive letters after the
internal hard drives.
A common plea in Win9x newsgroups was: "I just added a new hard drive (or
partitioned my existing drive), and now my CD-ROM drive letter is different
and that broke a whole bunch of stuff. HELP!"
This happened to me the first time I added a new hard drive to a PC with a
CD-ROM drive.
Ever since, I've made a habit of always changing the
CD-ROM drive to 'M:' when I get a new computer; that leaves me lots of room
to add new hard drive partitions without changing the CD-ROM letter.
There were also regular pleas for help in the Win9x newsgroups from people
who added a second hard drive and discovered that some of the partitions on
their first hard drive (i.e., D: and above) wound up with new drive letters.
(Caused by creating a primary partition on the new drive.) This also
happened to me the first time I added a second hard drive to a PC.
Note: the newer operating systems allow drive letters to be changed by the
user, but I believe most current versions of Windows still default to the
same letter sequence that has been used since MS-DOS days.
Here's part (somewhat edited) of a canned post I used to post regularly when
I was hanging around in Win9x newsgroups:
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Here's some more detailed information on how drive letters are assigned:
The first floppy disk drive will always be 'A:', a second floppy (if
present) will be always be 'B:'.
When MS-DOS/Win9x starts up, it assigns drive letter C: to the first primary
partition on the master drive on IDE channel 0. Then it assigns drive
letters in sequence to the first primary partition (if any) on additional
internal hard drives.
Once the first primary partition on each drive is assigned a drive letter,
then the OS starts over with logical drives in extended partitions. Any
logical drives on the first physical drive are assigned letters first, then
the logical drives on each additional physical drive in sequence.
After the first primary partitions and all the logical drives in extended
partitions are assigned letters, the OS then assigns letters to any
additional primary partitions on the hard drives, starting with the master
drive.
Once all the hard drives are done, the OS then assigns letters to CD-ROM
drives, Zip drives, etc.
So if you have two physical hard drives you can, to some extent, change the
order in which drive letters are assigned by choosing which type of
partition(s) will be on each drive. You have to have at least one primary
partition on your master (boot) drive; on the slave drive it's optional.
CD-ROM letter drive letters will always be assigned *after* the hard
drive letters. You can go into Device Manager and specify the drive
letters for CD-ROMs. On a new system, I usually set my CD-ROM drive to a
high letter (M:, for example) so it doesn't get changed if I add a new hard
drive or create more partitions.)
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I'm not sure about the order for external USB/Firewire drives, but they were
probably done after all the internal IDE/SCSI drives (of whatever type).
And I have no idea about the order used when a system has both IDE and SCSI
drives; I would _guess_ that the IDE drives would have been assigned letters
first, but that's just a guess.
--
Nick <mailto:tanstaafl@pobox.com>
"Natural laws have no pity." R.A.H.