1.2 ACCESS TIME DEFINITION AND TIMING
Access
time
is defined as the
time
from the leading edge
of
the first
step pulse received to
Seek Complete (including settling). All seek
times are
true
statistical averages and are calculated with a step pulse
period of
10 psec.
at
nominal power and temperature.
Track-to-Track:
Average:
Full-Stroke:
Average Latency:
8 msec. max.
40
msec. max.
95
msec. max.
8.33
msec.
1.3 STEP PULSE PERIOD AND SEEK METHOD
The step signal is a 2psec. minimum width pulse which initiates read/
write head motion. The step pulse period determines the access
method. The number of pulses determines the seek length. The step
pulse period must
be
between
3/lsec.
and 200/lsec.
Step pulses may
be
lost at periods greater than 200jJsec. For additional
information
on
step pulses and seek methods consult the Seagate
ST412
Interface
Manual.
1-2
ST251
1251
RI277R
Product
Manual, Rev.A
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