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4. OPERATIONS
This chapter, which describes the operating characteristi cs
of the Cartridge Disk System, contains three main sections:
the first illustrates and describes the control panels that
appear on the equipment; another contains operating pro-
cedures that apply to the controller and the disk drives;
anda third contains procedures for handling disk cartridges.
CONTROL PANELS
A stcndard Xerox equipment cabinet, which houses the
controller, disk drives, and power supplies, contains
two principal control panels: an operator control panel,
located on the front of each drive, and the controller main-
tenance ponel, installed at the rear of the cabinet. The
operator control panel is described first.
OPERATOR CONTROL PANEL
The Model 7251/7252 Disk Drives have one control switch
and four indicator lights; see Figure 14.
The switch and
the indicators are described below and are summarized in
Table 12 for quick reference.
LOAD/RUN SWITC
H
The LOAD/RUN switch is a two-position, rocker-type
switch that starts and stops the disk drive. Cartridges may
be loaded and unloaded when this switch is in the LOAD
position - and the LOAD indicator is lighted. After a car-
tridge is loaded and the equipment drawer closed, switching
to RUN starts the drive and brings the disk up to its normal
~
operating speed in about 60 seconds. During this time, the
read/write heads are moved to cyl inder 0 at the extreme
outer edge of the disk and loaded.
When the switch is
moved bock to LOAD, the disk decelerates to a stop in
about 15 seconds and the LOAD indicator will light.
I
[ --·1
._.
After the operator moves the switch to LOAD, the unload
sequence is inhibited until the system detects an index
mark on the disk surface. During a write operation, this
could prevent garbl ing of data.
LOAD IND ICATOR
The LOAD indicator is a white signal light indicating that
cartridges can be loaded or unloaded. This light goes off
whenever the LOAD/RUN switch is set to RUN, and remains
off when the disk is rotating.
READY INDICATOR
The READY indicator is a yellow signal light indicating
that the drive is ready to accept and execute orders from
the disk
Vo
program. The light comes on when the disk
is rotating at its nominal speed, the read/write heads are
loaded, and no other conditions exist that prevent seeking,
reading, and writing. The light remains on throughout
VO
operations.
It is extinguished when the LOAD/RUN switch
is set to LOAD.
CHECK INDICATOR
The CHECK indicator is an orange signal light indicating
that because of an abnormal condition, the disk drive may
not be able to write. This condition may be reset by
movin~
the LOAD/RUN switch to LOAD and then bock to RUN.
PROTECT INDICATOR
The PROTECT indicator guards against inadvertent writing.
1
The indicator glows and writing is inhibited whenev~r the
LOAD/RUN switch is changed from the LOAD position to
RUN. Write-protect is turned off to allow writing when thE
operator depresses the PROTECT indicator.
The operator
can set write-protect at any time by moving the
LOAD/RU~
switch to LOAD and then back to RUN.
I
00
•
Figure
14.
Disk Drive Operator Control Panel
Operations
2')
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