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The head is positioned over the desired track by means of a stepper motor/band assembly and its
associated electronics. This positioner employs a 3.6 degree rotation to cause a one-track linear
movement. When a write-protected diskette is inserted into the drive, the Write Protect sensor
disables the write electronics of the drive, and a Write Protect status output signal is available to the
interface.
When performing a write operation, a 0.013-inch wide (nominal) data track is recorded. This track is
then tunnel erased to 0.012 inch (nominal).
Data recovery electronics include a low-level head amplifier, a differentiator, a zero crossing
detector, and digitizing circuits.
No data-clock separation is provided.
In addition, the drive is supplied with the following sensor systems:
1. A track 00 sensor that senses when the Head Carriage Assembly is positioned at Track 00.
2. The two index sensors, each of which consists of a L.E.D. light source and a phototransistor,
are positioned so that a signal is generated when a index hole is detected. The drive can
determine whether a single- or double-sided diskette is installed. This output signal is present
at the interface.
3. The Write Protect sensor disables the drive's write electronics whenever a write-enable tab is
removed from the diskette (see Section 1.12).
1.4
DISKETTES
The drive uses a standard eight-inch diskette. Diskette$ are available with a single index hole orwith
index and sector holes. They also are available double- or single-sided.
Single index hole diskettes are used when sector information is pre-recorded on the diskette (soft
sectoring). Multiple index hole diskettes provide sector pulses by means of the index sensor and
electronics (hard sectoring).
1.5
MECHANICAL AND ELECTRICAL SPECIFICATIONS
The mechanical and electrical specifications of the drive are listed in Table 1-1.
1.6
POWER REQUIREMENTS
The power requirements of the drive are listed in Table 1-2.
1.7
INTERFACE CIRCUIT SPECIFICATIONS
The interface circuits are designed so that a disconnected wire results in a false signal.
Levels:
True
= +0.4 V, maximum
False = +2.4
V,
minimum
1.8
INCOMING INSPECTION CHECKS AND PROCEDURES
There are two kinds of recommended incoming inspection checks and procedures:
static and
dynamic ones.
The static incoming inspection checks include the minimum steps that should be taken to ensure
that the drive is operational when received.
1-2
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