Multi-platform distribution format (Was: Backups [was

Paul Koning paulkoning at
Mon Sep 21 11:34:03 CDT 2015

> On Sep 21, 2015, at 12:28 PM, Jay Jaeger <cube1 at> wrote:
> On 9/21/2015 4:30 AM, Johnny Billquist wrote:
>> On 2015-09-21 02:11, Jerome H. Fine wrote:
>>>> Chuck Guzis wrote:
>>> Note that the RX50 was the same.  DEC finally changed
>>> their marketing policy with the RX33 drive which used the
>>> same 3.5" HD floppy media as the PC.  It was actually
>>> possible to FORMAT those floppies under RT-11.
>> No, DEC actually did support users formatting RX50 floppies on their
>> own, but only on the Rainbow.
>>    Johnny
> There was also a standalone PDP-11 diagnostic program available that
> could do it.

For RX50?  On standard PDP11s, those used an MSCP controller, which means the controller would have to do it.  Did it?  The only MSCP controller I remember that did formatting was the UDA50.

I suppose you could on a Pro, since that had its own particularly disgusting junk controller.  But I haven't seen RX50 formatting there.  My impression was that they came factory formatted, with the DEC-specific 10 sector per track format.


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