dowson@utecfa.UUCP (Jim Dowson) (02/04/86)
I am trying to hook up a CDC 9877 (BK5XX) 80 Mb removable storage SMD drive
via a CDC 9090 multibus interface card to a Xenix system (3.0).
The pertinent specs for the drive are:
1) 20,160 bytes/track
2) 5 tracks/cylinder
3) 823 cylinders/spindle
4) 13,440 dibits/revolution (? allegedly)
The pertinent facts for the controller are:
1) 512 data bytes/sector
2) 63 bytes control information/sector
Here's the problem:
There are formulae in the installation manual that are as follows:
SL = 13440/RS (ignore remainder)
where SL = sector length
RS = required number of sectors (/track)
13440 = total dibits/revolution
PV = 4096 - SL
where PV = preset value to be encoded by the DIP
switches
Here's how I (tried to) figure it:
SL = 13440/35 = 384 (I want 35 sectors/track)
PV = 4096 - 384 = 3712
However, this doesn't work, nor does +/- 1 ...
Frankly, I don't understand where the 13,440 number came from - so I even
tried using 20,160 (the number of bytes/track) ... that didn't work either.
In all cases the error code from the controller indicated "sector pulse not
found".....
Help ......
Please mail responses to:
{ihnp4,allegra,decvax,linus}!utzoo!{spectrix,utecfa}!bml!jim
Jim Dowson