11/93 rebuild

[Paul Koning]

> On May 27, 2019, at 12:14 PM, Holm Tiffe via cctalk <cctalk at classiccmp.org> wrote:
> 
> Rod Smallwood via cctalk wrote:
> 
>> Hi
>> 
>>     Whilst I wait to hear from Glen Slick who has got me this far 
>> (Thanks Glen) I'll restate the problem.
>> 
>> 1. I now have an old XP system with SIMH on it (PDP11.exe)
>> 
>> 2.  I have created RD54.dsk containing RSTS/E
>> 
>> 3. Attached to the system is a 2.1Gb SCSI drive via an adaptec 2940 
>> controller
>> 
>> 4. I need a tried and tested list of step by step instructions to put 
>> RD54.dsk on the SCSI drive.
>> 
>> 5. The drive will then be moved to a CQD-220A/TM SCSI controller on my 
>> KDJ11-E based 11/93 and must boot.
>> 
>> 6. Its just an image copy from one drive to another on the same system.
>> 
>> 7. Nobody has come up with a tried and tested list of step by step 
>> instructions yet.
>> 
>> 
>> Rod Smallwood
>> 
> 
> I don't think that you have any chance to get that to work, since the
> data structures on the floppy disk will be different to that needed
> structure on the scsi disk. As far as I know the controllers put some
> kind of partitioning information to the disks too...

Floppy?  I don't see that mentioned.

RSTS can handle image copies without trouble if the sizes match, or if destination is slightly bigger.

Partitions -- there is no such thing on RSTS.

Writing disks is no problem if you have a program that can write raw block devies, and an OS that lets you do this.  Sufficiently old Windows can do this via the BIOS I/O machinery; I've done it for RX50 floppies though not for hard drives (don't have any).

RX50 floppies do have two complications: 10 sectors per track rather than the PC standard 9, and a sector layout with interleaving and track skew.  It's not hard to deal with this in software once you have the details reverse engineered.  FLX does this, it's how I've created PRO boot floppies on my PC.

	paul