Mail Archives: opendos/2001/03/20/20:06:40
Hi, Rob,
Rob McGee wrote:
> What I would like to do is leave Boot Manager out. Suppose for some odd
> reason you're not using some trick to multi-boot. That second primary
> partition on the primary master device would get letter "D" before the
> search goes to other physical devices, correct?
>
> The text you quoted from PowerQuest (before my initial post I tried
> consulting their Web site for this, too, but came up with nothing there)
> seems to say that only the first recognized primary partition per device
> gets the drive letter. That implies that subsequent primary partitions
> would get letters along with the logical partitions. But it does not
> specifically say so.
I mentioned Boot Manager only because it is probably the simplest way
(along with LILO) to organise a multi-boot system. Anyway, I have had
more experience with BM and OS/2's FDISK than I have had with LILO.
I know from experience that if I create two primary partitions on the
primary master and two on the primary slave, the drive letters will be
assigned as follows:
Drive Partition Letter
----- --------- ------
Master 1 C:
Slave 1 D:
Master 2 C: (Hidden)
Slave 2 E: etc.
Logical drives created after that will be assigned starting with all logical
drives on the Master and then all those on the slave.
Neither DOS nor OS/2 will recognise another primary partition on the master,
so it won't get a drive letter. FDISK can see them, but the OS can't.
> We know the primary master is first and the secondary
> slave comes last. But what's the order in the middle? :)
I have only ever had a maximum of three IDE hard disks attached (the fourth
IDE device is a CD-ROM), but the letters are still assigned to hard disks
on the primary controller before they are assigned to hard disks on the
secondary controller.
> Similarly, if a DOS-recognized partition type holds a non-DOS filesystem
> then DOS will just think it's unformatted. Unformatted media can have a
> drive letter. (You have to have a drive letter to use format.com.)
Currently, I have two hard disks and an IDE CD-ROM on my system. I have
Boot Manager and two C: partitions installed on the first hard disk. The
second hard disk (slave on the primary controller) is entirely divided into
logical drives, some of which are formatted for FAT32, and some of which are
formatted for HPFS. I boot Win98 from the first primary partition on the
primary master, and OS/2 from the second primary partition on the primary
master. Win98 cannot see the HPFS drives, but OS/2 can see the FAT32 drives,
because I am using a special FAT32 IFS for OS/2.
The partitions are organised as follows (Disk 1 is the primary master,
whilst Disk 2 is the primary slave):
Disk Partition Partition File Win98 OS/2
No No Type System Drive Drive
---- --------- --------- ------ ----- -----
1 1 Primary Boot Manager None None
1 2 Primary FAT32 C: C: (Hidden)
1 3 Primary HPFS C: (Hidden) C:
2 4 Logical FAT32 D: D:
3 5 Logical FAT32 E: E:
4 6 Logical HPFS None F:
5 7 Logical HPFS None G:
6 8 Logical HPFS None H:
The CD-ROM is Drive F: under Win98 and Drive I: under OS/2.
I can't tell Win98 to format hard disk Drive F:, because it thinks Drive F: is
the CD-ROM, and I can't tell it to format Drive G:, because it can't see the
partition. It will return an "Invalid Drive Specification" error. Win98 can
only see the HPFS partitions under FDISK, but they are not assigned a drive
letter.
Also, I was running RedHat Linux 6.0 for a while, and it had to be booted from
a partition on the primary master. I was obliged to create a small partition
(mounted as /boot) on the first hard disk. I created this partition with OS/2's
FDISK, then used RH Linux's Disk Druid to mark the partition as ext2. I also
made it a primary partition. OS/2's FDISK subsequently recognised the partition
as Type 83, and the other Linux partitions as 83 or 82 (for the Linux Swap
partition). However, OS/2 would not assign drive letters to any of the Linux
partitions without the use of a special IFS driver for ext2, and then they were
assigned out of order. (/boot, the last primary partition on the primary master
was assigned Drive I: and the other Linux partitions (I can't quite remember how
many there were) all got drive letters, and the CD-ROM still came last. (I think
the CD-ROM ended up as something like Drive M:)!
> PQ> Finally, CD-ROM drives and other types of removable media drives
> PQ> are assigned a drive letter.
>
> This isn't quite true. If your Zip is IDE or ATAPI and the media is
> present at boot time, its partitions will be assigned drive letters
> along with the real hard drives. The same is true for SCSI removables
> like Zip and Jaz, *if* the SCSI adapter has a BIOS. The distinction is
> whether or not a *software driver* needs to be loaded for the device by
> the OS, as opposed to BIOS recognition.
The information about removable media drives is from the User Guide for
PartitionMagic V3.0. Since PartitionMagic is now up to Version 6, I suspect
that that particular bit of info may be out of date. (The manual has a
copyright date of 1997).
Also, I have never owned a Zip, Jaz or SCSI drive, so I really don't know.
I do know that I can set my 1997 BIOS to boot from A:, C:, Zip, Jaz, SCSI
or CD-ROM, but how that works, I haven't the slightest idea.
> It is an interesting matter.
It certainly is.
Best regards
Chris Souter
(Sydney, Australia)
(csouter AT seltek DOT com DOT au)
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