Siemens 100-8, Техническое руководство

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R E C O R D I N G F O R M A T
T h e r e c o r d i n g f o r m a t
l s
d e p e n d e n t u p o n r e q u i r e m e n t s o f t h e c o n t r o l l e r . T h e t r a c k
a n d s e c t o r o r g a n i z a t i o n o f d a t a Is d e p e n d e n t o n t h e f o r m a t .
E n c o d i n g S c h e m e
T h e d r i v e a l l o w s d o u b l e - d e n s I t y o r s I n g l e - d e n s I t y e n c o d i n g s c h e m e s . I n d o u b l e -
d e n s i t y r e c o r d i n g , e a c h b i t c e l l Is 2 m i c r o s e c o n d s w i d e , In s i n g l e - d e n s Ity r e c o r d ­
i n g , e a c h b i t c e l l Is 4 m i c r o s e c o n d s w i d e ( s e e F i g u r e 1 - 3 ) .
T r a c k F o r m a t
T h e f l o p p y d i s k c o n t a i n s 77 t r a c k s . T h e f i r s t ( o u t s i d e ) t r a c k i s t r a c k 0 0 , a n d t h e
l a s t ( I n s i d e ) t r a c k Ls 76. D u r i n g t h e w r i t e o p e r a t i o n , a n e r a s e c o l l i n t h e
r e a d - w r l t e h e a d e r a s e s t h e o u t s i d e e d g e s o f t h e d a t a j u s t w r i t t e n , n a r r o w i n g t he
d a t a t r a c k . I n t h i s m a n n e r , a g u a r d b a n d Is e s t a b l i s h e d to p r o t e c t t h e d a t a f r o m
a d j a c e n t t r a c k c r o s s t a l k w h e n r e a d i n g .
-► 1 CELL
12
m
SEC
- * - ( 5 0 '0 KBS)
1 1 0 0 I 0 1 1 1 0 0 1
WRT DATA
FT
- ► ] 2
m
SEC f— -
I I
I I
I I
j u i m j u if
CLOCK CLOCK DATA DATA DATA
DOUBLE-DENSITY ENCODING (MFM)
CLOCK DATA
-
BIT CELL
4
iu
SEC
(250 KBS)
1
1
0
0 0 1
I
i i ! i i
WRT DATA
i n n n n r
¥
u n n r
j 2
m
SEC h - CLOCK DATA CLOCK CLOCK CLOCK
SING LE-DENSITY ENCODING (FM)
CLOCK DATA CLOCK
F i g u r e 1- 3. S i n g l e and D o u b l e D e n s i t y E n c o d i n g
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