Date   : Tue, 25 Aug 2009 12:49:43 +0000 (GMT)
From   : debounce@... (Greg Cook)
Subject: ANN: High Density: EDOSpat 4.82 / 5.12

Dear all,

I have updated EDOSpat to version 4.82 and split off a new version,
5.12.  EDOSpat applies speed and compatibility patches to Opus EDOS 0.4,
a double density DFS by Alan Williams.

http://homepages.tesco.net/rainstorm/#prog.edospat

Changes since version 4.40 include a fix to fast Tube transfers in
OSGBPB, large loads/saves in OSFILE and *RUN and various API
improvements.  EDOSpat now supports the following interfaces:

- WD1770, BBC B/B+ (tested in BeebEm)
- WD1770, BBC Master
- WD1770, Opus
- WD1770, Watford
- WD2791, Opus (tested)
- Opus Challenger (tested)
- Slogger Pegasus 400

Version 5.12 with the appropriate hardware will also read and write quad
density (high density) floppy discs, storing up to 592 KB and 248 files
per side.

The higher data throughput is achieved by simple NMI service routines
using the A and X registers for persistent storage.  I have checked the
ISRs for correct operation up to one NMI every 16us, even 15us in most
cases -- for the principle, see the article on BeebWiki:

http://beebwiki.jonripley.com/Quad_density_floppy_disc_access

Version 5.12 supports the WD2791 (tested) and WD1772PH02-02 'Ajax', and
only works with modified interfaces.  See readme.txt in the distribution
for details.  You'll be able to see a working example at the upcoming
Retro Reunited.  For stock interfaces please use version 4.82.

Sincere thanks for contributions from J.G.Harston and Steve Bass.

Regards,

Greg Cook
debounce@...
http://homepages.tesco.net/rainstorm/