> On Sep 14, 2017, at 12:27 PM, jim stephens via cctalk <cctalk@classiccmp.org>
> wrote:
>
>
>
> On 9/14/2017 9:19 AM, Fred Cisin via cctalk wrote:
>> You have some .dsk images of SSDD 96tpi for 11/73.
> I have some also, and would love if there is a writeup of a known working
> procedure to use as a reference.
>
> Having a list of programs and systems is great, but I'd also like to know a
> few formulas that absolutely worked for someone as a starting point.
>
> We have copies of a VMS 4.3 floppy set on RX50's which we will image as well,
> and using something other than the DEC hardware will be useful.
It's easy on Linux. PC 5.25 inch drives have settable format parameters. The
PC default is 9 sectors per track, but you can set it to 10 for RX50
compatibility.
At one point you'd do that with an entry in /etc/fdprm:
rx50 800 10 1 80 0 0x23 0x01 0xDF 0x50
There's still a command line approach, I forgot the command name though. You
can also do it under program control with the the FDSETPRM ioctl. I have some
Python code (in my "FLX" utility for operating on RSTS file systems) that does
this.
One complication: if you have an image which has the blocks in logical order,
you need to shuffle them to account for the strange track numbering,
interleaving, and track to track sector skew. Here's a program that will do
that. (It operates on image files, not on the actual floppy drive.)
paul
