Re: Dual Boot - Two Physical Drives


"Timothy Daniels" <NoSpam@xxxxxxxxxxxxx> wrote in message
news:%23c1tl0cCIHA.2004@xxxxxxxxxxxxxxxxxxxxxxx

"Pegasus (MVP)" wrote:

"Mac McMicmac" wrote:
I have two physical hard drives (IDE) - each running a single copy
of XP Pro/SP2. How can I have the computer somehow prompt
me for which HD I want to use when the computer starts up?
I have been physically switching the power cable and IDE ribbon
cable to the drive I want to use, while leaving the other drive
completely disconnected (both power and IDE).

My understanding of "standard" dual boot techniques (which
I could easily google for) is that those techniques assume two
OS installations on a single hard drive... which is NOT my
situation... thus the question here.


AFAIK you cannot do this with the basic Windows boot loader.
I assume that each disk has Windows installed on drive C:. While
both are installed then one would appear as drive D: or E:, which
will cause havoc.

Ntldr (the standard NT/2K/XP boot loader) can boot multiple
OSes from the same HD and from multiple HDs. The entries
in the boot.ini file which designate the OS locations (called
"ARC paths") have a parameter called "rdisk()" which
designates the physical HD. The argument "x" in "rdisk(x)"
stands for the position (beginning with 0) of the HD in the
BIOS'es Hard Drive Boot Order (i.e. HD boot priority).
The HD at the top of the list is "rdisk(0)", and the files in the
Primary partition that is marked "active" on the HD will
control booting. Other HDs in the Hard Drive Boot Order
will be designated as "rdisk(1)", "rdisk(2)", and "rdisk(3)",
depending on the number of HDs in the system. The
*default* Hard Drive Boot Order is a subset of:
Master on IDE ch. 0, Slave on IDE ch. 0,
Master on IDE ch. 1, Slave on IDE ch. 1.
If there is not a HD at one of the above positions, that position
is merely skipped when the BIOS builds its Hard Drive Boot
Order list. And of interest to the Original Poster, that order
can be manually adjusted in the BIOS by the User at startup
time. That setting will persist in ROM from startup to startup.
Thus, with a separate OS on each HD, each with its own
boot files, one can accomplish multi-booting via the BIOS.

Since the OP's two copies of XP were apparently installed
independently (i.e. one being out of view of the other OS's
installer), each will call its own partition "C:" WHILE IT IS
RUNNING, and it will call the other partitions by other single-
letter names. This is NOT a problem as long as the partitions
do not have shortcuts that refer to OTHER partitions.

*TimDaniels*



Thank you for the informative and helpful answer. FWIW, I'm a developer and
support a production system based on .NET 1.1 and SQL Server 2000. We are
migrating the whole thing to .NET 3.5 and SQL Server 2008 (both of which are
not yet RTM). So I have two development environments which should have
nothing to do with each other - thus the separate physical disks. When the
2008 products are finally RTM I'm going to reimage the disk that currently
has the beta versions. When I'm working in one environment there is
absolutely no need to see the other - so no shortcuts between the two disks.
I do not want to have two completely separate development workstations - so
two physical disks gets me what I need and want. I rarely switch between the
two environments - but I do it enough that it's a hassle and I'd prefer a
way to chose from a menu when I power up.

Thanks again!


.

Relevant Pages

  • Re: Dual Boot - Two Physical Drives
    ... I have been physically switching the power cable and IDE ribbon ... BIOS'es Hard Drive Boot Order. ... and it will call the other partitions by other single- ...
    (microsoft.public.windowsxp.general)
  • Re: IDE and SATA
    ... SATA drive you should have no problems. ... Enable IDE hard drive as first hard drive boot device ...
    (microsoft.public.windowsxp.general)
  • Re: IDE and SATA
    ... Enable IDE hard drive as first hard drive boot device ... I'm thinking of SATA. ... I know that back in the days of NT, if I had both IDE and SCSI in a pc ...
    (microsoft.public.windowsxp.general)
  • Re: IDE and SATA
    ... Enable IDE hard drive as first hard drive boot device ... I'm thinking of SATA. ... I know that back in the days of NT, if I had both IDE and SCSI in a pc ...
    (microsoft.public.windowsxp.general)
  • Re: Boot.ini question
    ... that utterly flouts the whole point of the rdisk() parameter. ... Having the rdiskparam the ordinal in the hard drive ... One problem is that if the order in the hard drive boot order list ...
    (comp.sys.ibm.pc.hardware.storage)