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Self Seek option (SS)
This option is provided as a method to continuously exercise the
drive.
with shorting plug SS installed, the drive continuously exe-
cutes a "butterfly" seek pattern.
The drive need not be connected to
a SCSI bus.
No test results are given, but if the drive stops, a
malfunction has occurred.
Drives are shipped from the factory with SS disabled (shorting plug
SS not installed).
Reset option (RO)
Shorting plug RO determines whether a drive responds to the SCSI bus
signal -RST (reset) with a cold reset (plug installed) or a warm reset
(plug not installed).
The Q250 and Q280 never assert -RST.
If cold reset is selected, (RO plug installed) the drive immediately
performs a POR (Power-On-Reset) when the -RST signal is detected: it
resets all drive functions including write to disk, performs a com-
plete recalibration, reevaluates all shorting plugs except wait Spin,
and goes to the SCSI bus free phase.
Unrecoverable read errors may
result if a drive is cold reset while writing.
Cold reset typically
takes six seconds, during which time the drive cannot respond to
commands.
If warm reset (RO plug not installed) is selected and the -RST signal
is detected, the drive completes writing the current sector, performs
a partial servo resynchronization, and goes to the SCSI bus free
phase.
Warm reset typically requires 200 ms.
It is particularly
useful when the host issues multiple -RSTs.
Both warm and cold resets meet the ANSI requirements for a "hard"
reset.
Drives are shipped from the factory set for warm reset (RO
plug not installed).
External LED (W1)
If an external LED will be connected to J6, remove shorting plug W1.
Leave W1 installed to use the LED on the face of the drive.
Drives are shipped with W1 installed.
Spare Shorting Plug (P1)
For the convenience of customers, drives are shipped from the factory
with a spare shorting plug installed in position Pl.
No drive func-
tion is affected by Pl.
2-18
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