A drive may
be
designated a particular unit number, subject
to
the restriction that different
units
on
the common
110
bus must not
have
the same number assigned. Since the
switches in different units
are
not interlocked, if two (or more) drives are accidently
assigned the same unit number and that number is then selected by the
controller,
undefined operation may occur.
CAUTION
LOSS OF
DA
TA
MA Y OCCUR IF THE UNIT NUMBER
SELECTOR SWITCH IS REPOSITIONED DURING A
WRITE OPERA TION.
3.9
CE
AUGNMENT
Prior to plaCing the disk drive into operation, It Is recommended that the
CE
alignment
procedure contained in Section
VI
be
performed. Because misalignment
of
only
200
jJ.inches
is significant
and
PERTEC
cannot control the amount
of
shock a unit may
encounter during shipping,
it
is recommended that the
CE
alignment procedure
be
performed on
100
tpi models; the
CE
alignment Is mandatory
on
200
tpl models.
3.10
PERIODIC MAINTENANCE
Periodic
maintenance requirements
of
the disk drive
are
detailed
In
Section
VI
of
this
manual.
Periodic cleaning
of
heads and disks,
and
fitter changing should
be
performed
according
to
the prescribed schedules and procedures.
3.11
INTERLOCK
PROTECTION
The operator should not attempt to torce or override the various protection Interlocks
provided by the disk drive. These Interlocks
are
designed to prevent damage to data
contained in disk cartridges,
and
to
the disk drive equipment. Front load models are
interlocked by a switch which senses when a cartridge is correctly Inserted
Into the
receiver. When a cartridge is not inserted in the receiver, or the cartridge is Incorrectly
inserted, the switch
will not
be
actuated and this condition is sensed by the logic which
prevents the disk drive from responding to
RUN/STOP operator commands and STARTI
STOP
DISK
DRIVE
interface line commands.
If the door is not properly closed on front load models, either
as
a result
of
the cartridge
being incorrectly inserted or because
of
operator error, the switch will not
be
actuated by
the cartridge; this results from the fact that
as
the receiver lowers a properly inserted
cartridge down onto the spindle clutch, the cartridge body
(If
it
Is In the correct position)
actuates the switch lever. Additionally, the door is locked whenever the disk drive is not in
a
Safe condition. The Safe condition is indicated when the SAFE indicator is illuminated.
Top load models are interlocked
by
a switch which senses the postlon
of
the cartridge lock
arm. This switch
will
be
actuated only when the lock arm is fully rotated toward the spindle
and when the correct height is sensed
by
the cartridge lock arm. This condition will exist
when a cartridge has
been
correctly seated on the aligning keys and the cartridge bottom
cover has
been
correctly positioned over the top of the cartridge. In the case
of
an
incorrectly inserted cartridge, or when a cartridge having a non-compatible bit density
rating is inserted, the correct height
will not
be
sensed by the switch and therefore the disk
drive will
be
unable
to
respond to RUN/STOP operator commands
or
START/STOP
DISK
DRIVE
interface line commands. Additionally,
if
a cartridge is inserted without a cover, or
only a cover is inserted, the correct height
will not
be
sensed
and
the disk drive will not
respond to commands.
3-9
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