[Coladam] Delete a backup file on DDP

geoff at oltmansfamily.org geoff at oltmansfamily.org
Thu Jan 28 16:02:21 CET 2010


Thanks.

I'm trying to get rid of a couple bugs in ADAMEm/SDL. Namely the disk image
write routines aren't working properly for some reason. 

For example if I attempt to use clone21 from TDOS and write a disk image to
a blank disk, it's not writing the blocks in the right locations. ADAM 160k
disk images are interleaved 5:1 (or is it 1:5?), so disk sectors aren't
stored sequentially. The code in ADAMEm does this calculation properly, but
when I look at the resulting image in a hex editor, things aren't correct.
For example, the first write that clone does should be to block 0, which
should also be offset 0 in the resultant disk image file. In my case
though, it is several kb past the beginning of the file.

It is using the C standard library functions fseek, fread, and fwrite for
disk image operations. The calculation for block 0 in fseek is correct, but
when the subsequent call to fwrite occurs, it is writing to the wrong
position in the file. I don't get it. I've used these functions before in
my own software, and disk reads appear to work just fine and the same
calculations to offsets in the file are correct there.

On Thu, 28 Jan 2010 08:28:14 -0500 (EST), "Rich Drushel" <drushel at apk.net>
wrote:
> On Wed, January 27, 2010 9:58 pm, Geoff Oltmans wrote:
>> Since we're on the subject of the ADAM filesystem, does anyone have
>> documentation describing on the filesystem (directory format)? I haven't
>> checked the ATM, I suppose it'll be in there.
> 
>     At the end of my commented EOS 5 (6) source listing is a description
> of the directory format:
> 
>     http://drushel.cwru.edu/atm/eos52.asm.html
> 
> and page down almost to the end.
> 
>     *Dr. D.*
> 
> -- 
> Richard F. Drushel, Ph.D.            | "They fell:  for Heaven to them no
> hope
> Department of Biology                |  imparts / Who hear not for the
> beating
> Case Western Reserve University      |  of their hearts."
> Cleveland, Ohio  44106-7080  U.S.A.  |         -- Edgar Allan Poe,
> "Al-Aaraaf"
> 
> 
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