Sharp FDD-412A - Page 105

S23
5.3.1
(1)
(2)
FDD412A/B
Medium Management
Necessity of Medium Management
Floppy disk-related errors (|
100b
100 100
| 1]
|
Figure 5.32 shows how errors
occurred in a device using
floppy disks.
As
can
be
seen
fromthe
figure,
the
errors
related
to
floppy
disks
were
on
the
rise
while,
the
device
was
boosted
in
reliability. This situation
cannot
be
tolerated.
Trend
(96
Jee
50k
Trend
of
error
Percentage
of
disk-'
reduction for entire | reduction for read/ relaced errors in |
. “ Idevice write section read/writ !
Figure 5.33 compares read/ ———_
write errors between work disk
and system disk, indicating a
disproportionately high fre-
quency of errors on work disks
that
are
more
often
handled
is
manually
than
system
disks.
100
Fig. 5.32 Trends of Error Occurrence
Given
such
a
close
relation-
ship
of
floppy
disks
to
read/
write
errors,
however,
adequate
ol
|
|
medium
management
procedures
|
Work
disk
errors
|
$
are
yet
to
be
established.
as
ie
es
ee
Medium
management
is
getting
more
important
as
floppy
disks
Fig.
5.33
A
Comparison
of
Work
Disk
are
more
often
used
for
more
Errors
with
System
Disk
data
density
from
now
on.
Errors
in
Percentage
50 |
vstem disk errors
Loss in system operation
The
losses
in
system
operation
due
to
floppy
disk~-related
read/write
errors
generally
fall
into
the
following
categories:
(a)
Loss
of
time
by
reexecution
of
job
(retry,
copy
into
another
floppy
disk,
reentry
of
all
data,
etc.)
(b)
Delayed
output
time
affecting
associated
departments
and/or
end
users
(c)
Increased
recoverable
errors
resulting
in
more
processing
time.
The
severity
of
actual
loss
will
depend
on
the
circumstances:
(a)
The
error
occurring
at
the
busiest
transaction
time
(b)
The
error
occurring
in
critical
data
(c)
The
error
occurring
near
the
computer
output
time
(d)
The
error
occurring
in
a
job
that
shows
significant
loss
when
_subject
to
reexecution.
As
described
above,
minimizing
losses
in
system
operation
requires
considerations
in
every
aspect
of
the
business
and
computing
en-
vironment.
—99—