Apple 13-0010--001 Computer Drive User Manual


 
ELITE SERIES USER MANUAL APPEN. B - DOS NOTES
The high four bits (7-4) of each entry are the
drive type code, the next three bits (3-1) are
the seek rate code, and the low bit (0) is the
single phase per cylinder flag.
0000 XXXX = Disk II
0001 XXYX = Elite One
0010 XXXX = Elite Two
0011 XXXX = Elite Three
XXXX 000X = Spiral Cam Seek Rate
XXXX 001X = Lead Screw Seek Rate
XXXX 0l0X = Band Pulley Seek Rate
XXXX XXX0 = Two Phases per Cylinder
XXXX XXX1 = One Phase per Cylinder
An additional piece of information can also be
obtained by using the [AY] pointer returned by
the enhanced DOS. That is the version number of
the enhancements applied to the DOS in use. It
is stored as a word at location [AY]+$1C and
[AY]$ iD, low byte first, high byte last. The
version is kept in binary coded decimal (BCD) in
which the hexadecimal digits $WXYZ would repre-
sent the version number WX.YZ. The low byte (YZ)
is the minor revision number, and the high byte
(WX) is the major revision number.
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