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

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> Do you have anything odd or excessively modern in your hard drive setup?

I don't think so, but...

> 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.

I'm really not sure how I set up my emulated DOS except for DRDOS 7.03 is
happy with a 2 gig drive and calls it FAT16B > 32M. I *thought* I gave my
MSDOS 6.22 system 2G also but fdisk on it only shows me 1G. 

> 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.

I am starting to remember this now. My real DOS partition that I stole from
my Linux swap is 2G and that's how big I built the filesystem...and DRDOS
and 98SE boot disks can read it fine and so can FreeDOS. But...it's more
than 1024 into the drive which from your explanation I am wondering if this
is why fdisk on the real drive either fails or on DRDOS 7.03 gives me a
weird partition table that I am afraid to touch. Format failed also, did
nothing. I was able to exec my autoexec.bat and my system was ok, I just
can't get the darn thing bootable. It is probably related to what you are
saying and at this point I have no way to get it on a real box because I'm
out of space other than my swap files which start about 6-10G into the
drive. 

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

Yeah thanks. I had in mind to create 3 2G partitions so I could install
several DOS but that may not even be possible. I wonder if jacking up the
numbers so the cylinders are bigger will help or if the limitation is not
just on cylinders.

I thought 512M would be plenty too but after I installed only a few DJGPP
zips and OpenWatcom it was already getting pretty full so I figured I would
go for the biggest DRDOS would tolerate which seems to be 2G. I'll have to
plan a little more carefully when I learn the limits of each DOS version.

> "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.

Yes, it does seem to work better and even run after I booted into it with a
boot CD and did my autoexec bat after switching to C:. But I didn't check
to see if MASM/PWB would crash it yet.

I may look into creating my own boot disk with the full DRDOS install using
some tools I found on the net. That seems to be the only hope for installing
on my present setup but because of the CHS stuff that may not work either. 
It will be a little while until I get my old box fixed up. Bummer for me!

Thanks guys.

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Re: How can I install DOS without a floppy drive? Kulin Remailer <remailer@reece.net.au> - 2011-02-02 17:50 +0000

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