6.14
CE
ALIGNMENT
PROCEDURE
The circumferential and radial alignment of a disk drive is performed using a special
CE
disk cartridge that
can
usually
be
identified by a special top color
and/or
label. The
CE
cartridge disk contains two pre-recorded cylinders which are used to adjust the
Read/Write head radial alignment and the index to data Circumferential alignment.
CE
alignment procedures for a front load disk drive
differ
from that used with a top load
model. Primarily, the differences are due to the differences between the top load and front
load
CE
disk cartridge configurations. The alignment tracks used are at different locations
and the
read
data patterns
for
radial alignment
are
dissimilar. Therefore, separate
CE
alignment procedures
are
given for front load disk drives and top load disk drive. The
200
tpi radial alignment procedure is given separately in order to stress key elements.
Paragraphs
6.14.1
and 6.14.2 provide descriptions
of
front and top loading
CE
disk
cartridges; Paragraph 6.14.3 describes the environmental stabilization requirements for
the
CE
cartridges.
The test configuration for both top loading and front loading machines is given in
Paragraph 6.14.4.
Paragraphs 6.14.5 and 6.14.6 detail the radial
and
circumferential alignment procedures,
respectively, for front loading models. Paragraphs 6.14.7 and 6.14.8 detail the radial and
circumferential alignment procedures, respectively, for top loading models.
6.14.1
FRONT LOADING
CE
DISK CARTRIDGE
The
100 tpi front loading
CE
disk cartridge contains two pre-recorded cylinders
(095
and
100) which
are
used during adjustment procedures to the head/arm carriage assembly and
to the (upper) photoelectric sensor. The
200
tpi
CE
disk cartridge is identical to the 100 tpi
cartridge except that the two pre-recorded cylinders
are
190
and
200.
CAUTION
CARE SHOULD BE TAKEN
TO
ENSURE THAT CYLINDERS
090 THROUGH 110
ON
100
TPI,
OR CYLINDERS 180
THROUGH 210
ON
200 TPI,
ARE
NOT
INADVERTENTL Y
WRITTEN
ON;
WRITING
ON
THESE CYLINDERS WILL
CAUSE THE PRE-RECORDED DATA
TO
BE DESTROYED.
6.14.1.1
Cylinder
100
(100
tpi)
Cylinder
100 is used for adjustment
of
the head/arm location
on
100 tpi disk drives.
Cylinder
100 consists of
an
eccentric cylinder with
an
average radius of cylinder 100.
Radial adjustment
of
the head is carried out by monitoring the
read
signal envelope at
cylinder
100. Due to the amount of eccentricity, when a head is reading the pattern
and
the
head is mis-aligned from the true cylinder radius, then a lobed envelope pattern
will
be
produced. As the head is aligned to the true cylinder radius, a pattern with no lobes, or
minimal envelope lobing,
will
be
produced when the IBM or 3M-type
CE
cartridge is used.
When
using the CDC-type
CE
cartridge, the pattern will
be
as
shown in Figure 6-25.
6.14.1.2
Cylinder
200
(200
tpi)
Cylinder
200
is used for adjustment
of
the headlarm location
on
200
tpi disk drives.
The
alignment pattern for
200
tpi front load is identical to that used
on
200
tpi top load disk
drives. Refer to Paragraph
6.14.2.1
for description.
6·51
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