Spectravideo SVI 318 Service – Technical Manual page 118

A l s o du r i d n g wr i t e , two a dd i t i o na l s i g na l s a r e p ro v i d e d f o r w r i t e p recompen­
s a t i o n . The s e are
th e W D p u l s e a p p e a r i n g o n ( P in
whe n t h e W D pu l s e i s t o be wr i t t en
th e WO pu l s e i s p re s e n t , t h e WD pu l s e i s t o b e w r i t t e n a t nom i na l .
p r e c ompe n s a t i o n va l u e s va r y f rom d i s k ma nu f ac t u re r t o d i s k ma n u f ac t u re r , t h e
ac t u a l va l u e i s d e t e rm i n e d by s e ve r a l o n e s h o t s o r de l a y l i n e s wh ich a r e
l o c a t e d e x t e r n a l t o t h e FD 1 7 9 3 .
LATE
a re v a l i d f o r t he du r a t i on o f
WR ITE ?RE COMP EN SAT ION
Wr i t e
p re c ompe n s a t i o n ( wh i c h c o un t e r a c t s th e
a re p l a ce d c l o s e toge t h e r o n t he m o r e c r ampe d i n s i d e t racks ) i s ava i l ab l e t o
t h e u s e r on a n y t r ack s th a t h e f e e l s ne c e s s a r y .
STATUS REGISTER SUMM A RY
1
A LL TYPE
B I T COMMAN D S
R
NOT EADY
S 7
S 6 WR I TE
PROTECT
s s
HEAD LOAD ED
S EEK ERROR
S 4
!
CRC ERROR
S 3
I
I
0
S 2
TRACK
S l I N DEX
BUSY
s o
EARLY
( P i n 1 7 ) a n d
30 )
i s to b e w r i t t e n e a r l y .
LATE .
The wr i t e p re c ompe n s a t i on s i gna l s
WD
READ READ
A DDRE S S S ECTOR
NOT READY NOT READY
0
0
R ECORD
TYP E
RNF RNF
CRC ERROR CRC ERROR
LOST DATA L OST DATA
Q Q
DR DR
BUSY BUSY
4 . 85
LATE EARLY
( P i n 1 8 ) .
I EARLY
f bo t h
FM Mfll
in b o t h a n d
' d r i f t i ng ' when f l u x t ra n s i t i o n s
READ
TRACK
NOT READY
0 0
0
0
0
LOST
DATA
Q
DR
BUSY
is a c t i ve t r u e whe n
LATE i s ac t i v e t r u e
LATE
and a r e l ow whe n
S in c e wr i t e
EARLY
a n d
f o rma t s .
WR ITE
WR ITE
S ECTOR TRACK
NOT . READY NOT R EADY
WR ITE WRITE
PROTECT PROTECT
WR ITE WR ITE
FAULT FAULT
0
RNF
0
CRC ERROR
LOST DATA LOST
DATA
Q
DRQ DR
BUSY BUSY