Specifications
:
--
- .
:
_I
- .
:
...
:
'.'
:
..
'
•
u
.1
· u
• u
•
II
• u
•
\t
· \
-STEP
-SEEK
COMPLETE
-DRIVE
SELECT X
NOTE: VARIES WITH SeEK
L~NGTH.
11
••
mMC
MIN,
.a.o
maec MAX.
FIGURE
2·8.
BUFFERED
STEP
MODF
Shipping
Zone
The read/write heads can
be
accessed to the shipping zone
by
doing.
seek
to
cylinder
353
.
NOTE
STEP pulses with periods between 200"sec
and
3.0 msec are not permitted. Seek ac-
curacy
is not guaranteed
If.
this
timing requirement is
violated.
2.2.4 Head
Select
2-
and
2
1
These
two
lines
provide
for
the selection
of
each individual read/write
head
In a"binary coded sequence.
HEAD
SELECT
2°
is
the least
significant
line. When
all
HEAD
SELECT
11nes
are
false,
head 0
will
be
seleded. Table 2·1
shows the
HEAD
SELECT
sequence and
model
variations
for
the
HEAD
SELECT
lines.
See
figure
2-7
for
the
tim-
ing sequences.
,"
TABLE
2·1.
HEAD
SELECT
(1
=FALSE, 0 =
TRUE)
!
HEAD
SELECT
LINE
HEAD
SELECTED
HEAD
SELECTED
20
2
1
701
712
1
1
0
0
0 1 1
1
1
0
IMPROPER
SELECT
2
0
0
IMPROPER
SELECT
3
I
••
l
• I
·
·
'-'
· -
••
1
· -
••
I
• !
..
,
•••
HEADS SWITCHED
READ DATA
VAUD
+ WRITE GATE
WRITE DATA
(FROM
CONTROLLER)
VALID
-...-..--...1
-.f
~
8 "lee
MAX
-.-.-_1
l I 8 "aec
-
.....
-
....
1
'1
~(
FORMAT SENSITIVE)
~
~
400
naec
MAX
____
I
1-.
__
FIGURE
2·7.
HEAD
SELECTION TIMING
2·5