ACT apricot - Disk Format; Disk Insertion;Removal; Write Protecting

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DISK DRIVE

Di~k

Insertion/Removal

Insert

the

disk

into

the

drive

shutter

side first,

with

the

metal

centering

hub

facing 'downwards.

The

disk

should

slide

into

the

drive

with

the

minimum

degree of force.

Immediately

the

disk is inserted,

the

head is

momentarily

loaded to

seat

the

disk

properly

onto

the

drive spindle.

This

causes

the

front

panel

activity

indicator to be briefly

illuminated.

Improper

insertion

results

in

the

disk

not

being

accepted by

the

drive.

Remove

the

disk by pressing

the

front panel disk eject

button.

The

disk eject

button

should

not

be pressed,

whilst

the

activity

indicator

is

illuminated.

Write Protecting

The

method

of

write

protecting

the

disk is different

on

the

two

versions of disk.

The

earlier versions feature a Write

Protect tab, located

on

the

rear of

the

disk

in

the

lower

right

corner. Breaking off

the

tab

prevents

any

further

data

being

written

onto

the

disk.

The

tab

then

should

be

inserted

into

the

bottom

of

the

recess

at

right

angles to

its

original

orientation

(i.e. as close as possible

to

the

lower edge of

the

disk). Write

protected

disks

can

be

rewritten

on, by

moving

the

tab

to

the

top of

the

recess.

On

the

later

versions of

the

disk,

write

protecting

the

disk

is achieved

by

sliding

the

tab

to

the

lower position, creating

a

window

in

the

lower

left corner of

the

disk.

To

allow

the

disk to be

rewritten

onto, slide

the

tab back over

the

window.

Disk

Format

Each of

the

70

tracks

on

the

disk

is

divided

into

sectors

under

software

control

(Le.

soft sectored),

with

the

beginning of

each

track

indicated

by

the

index

pulse

generated

by

the

drive

motor

assembly.

The

software format

chosen for

the

disks is a derivation of

the

IBM

system

34

format for 8

inch

disks.

This

uses

double

density

MFM

encoded data,

with

9 sectors

per

track

and

512 bytes per

sector.

The

total

storage capacity of

the

70

track

disk

is

thus

315 Kbytes of

formatted

data

(9x70x512 bytes).

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Other manuals for ACT apricot

Service Manual305 pages