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Re: How can I install DOS without a floppy drive?

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Kulin Remailer <remailer@reece.net.au> wrote:

>Hi Dave and Rod,

>Thanks for your posts. I'm missing something here.

>I created a zip file of an installed DOS system and got it onto my Linux
>host. My plan was to try to boot a DOS boot disk and follow your
>instructions to format a partition I already have created, but for some
>reason the boot disk only recognized my A: drive. I got the abort/retry/fail
>prompt when I tried to dir c: or dir d: etc. 

>I was going to use one of my swap partitions as a home for a real DOS since
>it's 2G. Using Linux fdisk I changed the partition id to 06 hoping DOS would
>recognize it.

>But when I boot the DOS boot disk I can't get DOS fdisk to run, it says C:
>drive isn't accessible. If I could format/s the partition I was planning to
>just go back to my Linux box and unzip the installed DOS over the filesystem
>hopefully giving me a real bootable DOS. But the DOS bootdisk doesn't see
>the drive. I wonder if this is because I have partition types that weren't
>known to DOS.

>I am trying to find a tool that lets me install a bootloader in a FAT
>partition from Linux, that would solve the problem, because I can get the
>system over there, but I haven't found anything yet. I just can't get it
>bootable.

>I am afraid to try a more modern bootdisk (XP for example) since XP has a
>tendency to try to own the PC and feels free to write on the disk without
>asking. I don't want to lose my Linux.

>Do you have any idea what could be wrong, why doesn't DOS6.22 see the hard
>drive? Thank you.


Do you have anything odd or excessively modern in your hard drive setup?
DOS needs to access the drive via BIOS.

I still use DOS 5 for most of my DOS systems, but I believe 6.22 has similar
limitations:

DOS 5 doesn't support FAT32 and won't support a partition larger than
slightly under 2G ... And it accesses the drive through C,H,S addressing,
which can't support a cylinder larger than 1024.

For many systems, the combination of FAT16 and CHS addressing results in
a maximum usable partition size of just under 512M (Depends on how your
BIOS translates larger drives to this interface). I believe it is possible to
get DOS to work in LBA ... but I've never bothered to figure it out as 512M
is lots big for anything I do under DOS.

And to make matters worse, the partition offset has to be within the 1024
cylinder boundary from the start of the drive.

So - when multi-booting older DOS  it's best to make the DOS partition
first on the drive, and small.

"newer" DOS such as MS-DOS 7 (the DOS under Win9x), PCDOS-7,
OpenDOS-7 etc. know how to talk to larger drives may not be so
restrictive.

Dave

--
dave10@     Low-cost firmware development tools:  www.dunfield.com
dunfield.   Classic computer collection:  www.classiccmp.org/dunfield
com         

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Re: How can I install DOS without a floppy drive? Dave.Dunfield@use.techsupport.link.on.my.website (Dave Dunfield) - 2011-02-01 22:38 +0000
  Re: How can I install DOS without a floppy drive? Kulin Remailer <remailer@reece.net.au> - 2011-02-02 14:45 +0000
    Re: How can I install DOS without a floppy drive? Dave.Dunfield@use.techsupport.link.on.my.website (Dave Dunfield) - 2011-02-02 15:42 +0000

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