[vox-tech] rescuing winxp?

[Peter Jay Salzman]

On Fri 24 Sep 04, 12:21 PM, Mark K. Kim <lugod at cbreak.org> said:
> On Fri, 24 Sep 2004, Rick Moen wrote:
> 
> > That is correct.  SYS.COM copies several files (io.sys, command.com,
> > msdos.sys, and at least one other that I've mercifully forgotten about)
> > with the read-only, hidden, and system flags set, to the indicated FAT
> > filesystem.  One of those gets written to a specific physical location
> > so as to be findable by the Int13h boot service, early in the boot
> > process
> [snip]
> 
> Starting at some DOS version, the physical location thing became no longer
> necessary.  I'm not sure which version but somewhere around DOS 4-ish.
> Apparently the DOS bootstrap code became smarter and figured out ways to
> search for those files in the FS.  As a consequence, the "system" flag on
> those system files (which tells the OS and utility tools like Norton and
> PC Tools not to move those files from their physical location) no longer
> became necessary as they were before.
> 
> To re-install the MBR, another important component for booting DOS and
> Windows, uses FDISK's *undocumented* flag:
> 
>   FDISK /MBR
> 
> Once I told someone to do that over the phone and he freaked out (because
> "FDISK is dangerous!")  I'm not sure if he had the guts to go through with
> it...
> 
> -Mark

>From Rick's earlier posts, it sounds like all the nameless MS 0th order
bootloader does is pass control to the zeroth sector of the bootable
partition.

Does that mean that XP has the same MBR as Win95?

What I'm getting at is, can I use an old DOS fdisk to rewrite a MBR on a Win
XP machine?

Pete

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