[Coco] Backup of HDB-DOS drives

[gene heskett]

On Tuesday, January 17, 2012 05:56:22 AM Bruce W. Calkins did opine:

> ----- Original Message -----
> From: "Jim Hickle"
> 
> I'd like to backup HDB-DOS drives from one device to another. I have
> SCSI drives. Perhaps I could use BACKUP in a loop but don't know if
> it's possible for HDB-DOS to address two different devices.
> 
> I'm thinking of using NITROS9 with a device descriptor set up for source
> and destination HDB-DOS, open each as a raw device, and copying 256 *
> 35 * 18 bytes. Do we have a program like Linux's 'dd' ?
> 
> ===========================
> 
> For my RGB-DOS system I wrote a FOR : set drives : BACKUP :switch drives
> : BACKUP : NEXT loop from one hard drive to my ram drive and back to
> the other hard drive.  I never did find any was to copy directly from
> one hard drive to the other.
> 
> Bruce W.

I wrote a dd.b09 3 or 4 years ago, but I haven't inflicted it on anyone 
else as it is very very slow for some reason even with verify turned off on 
the target disk.  Its a bit tricky because after the first sector, lsn0 has 
been written, os9 throws up a disc change error, so you have to write that 
sector, close the path, and re-open it before os9 will allow the image to 
continue to be written.  I'm sure there is a magic twanger that will write 
at a decent speed, usually in odd values of interleave from the default of 
3, but that then slows the subsequent read performance too.

On the face of it, a simple "copy #56k /d0@ /d1@" should work, but the disk 
change error kills it quickly.

For installing a new nitros9 release, I have been known to trick a second 
HD descriptor into thinking the .dsk image, once sz'd to the drive, was a 
separate floppy, and did the install without ever writing a floppy with 
that .dsk image.  But to make that work I believe you need to be using the 
Superdriver disk system which can do 'partition' offsets.

Lots of creative ways to skin that cat.

Cheers, Gene
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