RLV11/RL02 ->11/73? - test-drb@ccmp.vtda.org

4 Apr 1999

...
 Zane H. Healy wrote:
 >I'e done it with both using the correct backplanes.  As I remember the
 >SMS1000 is a bit strange in the boot deperatment. Jerome Fine replies:
...
 My box has a single 8" floppy which is DSDD in
capacity for a total of
1976 blocks.  The drive is also set up the detect SSDD floppy media
as well as DSSD and SSSD media.  BUT, the device type is for the
MSCP emulation.  AND the DSDD interface switches from side 1 to
side 2 for each cylinder (or track since there is only one double-sided
surface) within the firmware.  Since this behaviour is outside the control
of the device driver (MSCP is DU:), the use of DSDD media is quite
a surprise as compared to the RX03 implementation on a DSD
880/30 which uses the same floppy media, but uses the whole first
side of the media followed by the second side of the media as
programmed within the DY(X).SYS software device driver in
RT-11. 
These block-numbering issues are addressed by Chester Wilson's
"DYC" handler, to an extent.  To quote from the documentation:

*This handler is designed for Sigma/Dilog RX03 controllers, with optional
*assembly  for  DEC,  MTI,  and DSD ones.  It may need minor modification
*(notably to the extended  addressing  and  formatting  code)  for  other
*manufacturers' boards.
*...
*In version 4, support for the SMS flavour of RX03 format has been  added
*(courtesy of discs from Billy Youdelman).

Sources to this code are available at

http://metalab.unc.edu/pub/academic/computer-science/history/pdp-11/rt/bill…

This code also knows how to format completely blank floppy disks into
DEC-compatible RX01 or RX02 on many third-party controllers under RT-11/TSX.

...
 As soon as I finish my tax returns and clean up a few
other
things 
Don't you have till April 30th up there?  (I have to get the
Canadian forms for the money I earned in Canada last year, still...)

-- 
 Tim Shoppa                        Email: shoppa(a)trailing-edge.com
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