Archiving MFM and RLL drives (Was: Re: Default password for Pick system on an AT?)

[Jules Richardson]

On Fri, 2005-06-17 at 01:35 -0500, Tim Riker wrote:
> Vintage Computer Festival wrote:
> >>As long as you don't hit a bad block.
> > 
> > Someone (I think Jules or Philip) figured out there's an option you can
> > specify on the command line to tell dd to skip bad blocks and replace any
> > bad sectors with zeroes.
> 
> dd conv=noerror,sync
> 
> is probably what you're after.

That's the one. It'll pad output with zeros where any bad blocks occur.
Keep a note of the dd output that goes to the terminal too (otherwise
you won't know years later which were bad blocks and which were
intentional blocks of zeros :)

Including output of 'fdisk -l' on the drive on the archive is useful too
as it'll tell you what geometry Linux is using for the drive (as well as
a dump of the partition table if it's of a type that fdisk understands).

In the case of MFM / RLL drives it'd be worth making a note of what
model disk controller the drive was hooked up to.

I have a feeling dd is available under Windows in the gnu utils port -
but it wouldn't surprise me if it doesn't understand reading from raw
disk devices (even assuming that Windows has the necessary support for
MFM/RLL disk controllers in the first place)

As for DOS - you'd *probably* end up writing some code to talk to the
disk controller; how complex that'd be I don't know.

cheers

Jules