Need good disk dump utility

Dwight K. Elvey dwight.elvey at
Mon Apr 25 13:17:18 CDT 2005

Hi Sellam
 I wrote some code to talk to a standard disk controller
that runs on a AT. I wrote it because I needed to get
the MFM information from disk that had the first track
set to FM while the others were MFM. I tried 22disk
without success being that my controller doesn't do
FM. In my case, the first sector being FM wasn't an issues
since I could format on my M20 but I needed to read the
other tracks.
 The code is written in Forth ( sorry about that ). If
you'd like to look at it, I can dig it out. It does
the standard DMA transfers on an AT. I don't recall
but I suspect it has little error checking.

>From: "Vintage Computer Festival" <vcf at>
>On 25 Apr 2005, Christian Groessler wrote:
>> > From Jules Richardson, 25. April 2005 16:25
>> >
>> > One thing that'd be useful would be a patched version of dd that could
>> > also retry reading bad blocks n times up to some command-line supplied
>> > maximum; quite often I find for marginal data (such as flakey floppies
>> > and hard disks) an initial read might work but one or more subsequent
>> > reads work find. Far as I know standard dd won't retry reading data at
>> > all.
>> I think sdd does all this.
>> See
>Thanks for all the feedback, everyone!
>I checked out sdd and it does not mention anything about errors.
>Nonetheless, I'll take everyone's input and get a Linux system running
>(something I've been meaning to do anyway).  If need be, I'll hack dd to
>make it work in a sane manner with errors, and will let everyone know
>about it at that time.
>In the meantime I've written a file extractor that handles the sector
>headers embedded in the Anadisk images and it seems to work pretty well.
>It was just more complicated than it needed to be.
>Sellam Ismail                                        Vintage Computer Festival
>International Man of Intrigue and Danger      
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