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(4) Removing disks from the disk drive
The procedure for removing disks from the disk drive is as follows.
STEP 1
Check to make sure that the drive select indicator is not illuminated before
pressing the push button. If the drive select indicator is illuminated,
execute CLOSE or RESET statement before you eject the disk. The drive
select indicator will turn off a few seconds after the execution of one of the
above statements.
Fig. 2.8 Removing Disks from the Drive
STEP 2
Firmly press the push button of the disk drive from which you wish to eject
the disk. The push button will return to the OFF position and the disk will
be ejected 2-3 cm from the drive.
CAUTIONS
1) Insert the disk into the drive slowly and carefully.
2) Check the orientation of the disk (write protect notch up, identification
label to the right) before setting the disk in the drive. (If the orientation
of the disk is not correct, the TF-20 will not operate.)
3) Always remove disks from the drive after checking to make sure that
the drive select indicator is extinguished. If you eject a disk while the
drive select indicator is illuminated, you risk losing the data stored on
your disk.
2-6
Push buttons
select indicators (LED)
3. DISKS
3.1 Disk Format
The flexible disks used in the TF-20 are double-sided, double-density
flexible disks. Double-sided means that data may be stored on both sides
(sides 0 and 1) of the disks by means of the read/write heads operating
through the access holes. Double density refers to the density with which
data can be stored on the disks.
The recording surface of the flexible disk is divided into 40 concentric
bands, called tracks. These are referred to, from the outermost to the
innermost, as tracks 0 to 39.
Each track is further divided into 16 sectors. These are the basic physical
unit of data storage on the disk. At the start of each sector is an area that
shows the start of the sector and contains the address data for the sector.
This is referred to as the identification or ID field. The ID field is followed by
the data field. This is where the data which the user wishes to store is
actually written. The amount of data that can be stored in a single sector is
256 bytes, or 4K bytes (1K byte = 1,024 bytes) per track for a total capacity
of 320K bytes for the entire disk.
3-1
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