>If it's an RX02 operating in double-density mode, you're not going to >read the disks with any commodity floppy controller. You will, however, >get the sector ID headers.
>DEC used a rather peculiar scheme where headers were recording in >single-density (FM), but the body of the sector (the data) is recorded >in a "peculiar" MFM, that employs some pattern substitutions to avoid >conflict with similar patterns in the headers. Thanks Chuck Hmm...I'll do some more checking with IMD and Anadisk tonight. I haven't looked at this disks in Anadisk yet. IMD did recognise some things...maybe it was the Sector ID headers. Even if I can't get anything off, I'm now very curious as to exactly what I'm dealing with. Terry On Fri, May 5, 2017 at 11:50 AM, Chuck Guzis via cctalk < cctalk@classiccmp.org> wrote: > On 05/04/2017 04:30 PM, js--- via cctalk wrote: > > > On 5/4/2017 6:16 PM, Terry Stewart via cctalk wrote: > >>> If these are from a VAX, could they be microcode disks for a > >>> 11/780? > >> There was a RX01 attached via a LSI-11 as console. > > > > And yet, if there were an RX02 somewhere on this VAX, I don't > > believe you'd be able to read them at all... RX02 seeming more likely > > with a VAX. > > If it's an RX02 operating in double-density mode, you're not going to > read the disks with any commodity floppy controller. You will, however, > get the sector ID headers. > > DEC used a rather peculiar scheme where headers were recording in > single-density (FM), but the body of the sector (the data) is recorded > in a "peculiar" MFM, that employs some pattern substitutions to avoid > conflict with similar patterns in the headers. > > A catweasel will work just fine--and there's code out there to handle it. > > --Chuck > > > > >
