[Coco] Backup of HDB-DOS drives

[Mark Marlette]

Just to be clear, this is not a limitation of hardware, but software, specifically HDB-DOS. 

Boisy wanted to retain the compatibility and not grow in to a 16k ROM. 

Under NitrOS-9 and SuperDriver, you can copy/backup/read/write from /x0-x3 to /i0-i1, s0-s7, etc..... 

Regards, 

Mark 
http://www.cloud9tech.com 

----- Original Message ----- 
From: "Robert Gault" <robert.gault at att.net> 
To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com> 
Sent: Tuesday, January 17, 2012 6:37:51 AM 
Subject: Re: [Coco] Backup of HDB-DOS drives 

Jim Hickle wrote: 
> 
> 
> 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' ? 
> 
> 

The Ken-Ton scsi interface used with the RGBDOS system could only address one 
scsi device at a time. I'd be surprised if the Cloud-9 interface is 
significantly different in this regard. As a result of the hardware limitation, 
RGBDOS could not copy or backup directly from one scsi drive to another. 

Bruce's suggestion of using an intermediate RAM drive (if you have 512K RAM) 
is a good one and about the only thing that will work with RGBDOS (or I suspect 
HDBDOS.) 
As Gene indicated, using OS-9 to backup HDBDOS drives needs to be done 
carefully to avoid errors generated by changing LSN0. Whether you run into this 
type of error will depend on the driver you use to access the HDBDOS drives. 
Written correctly, the driver should only see LSN0 of the OS-9 partition for 
the two scsi drives. The HDBDOS drives will be accessed using a sector offset 
value so there would not be a change to the LSN0 values. With this scheme, you 
would need a custom track copy program, Backup would not work. 

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