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1.
APLCHK
-
Application
Check.
This
is
a one work
'magic'
number
(5F10
hex)
used
to
determine
whether
this
is
an
application
load
file.
Its
presence ensures
that
a
simple
misnaming
of
a
file
to
have an
application style
extension
will
not
cause
a catastrophe.
It
should
be
noted
that
attempting
to
execute a
badly
formed
application
load
file is
quite
likely
to
cause
the
handheld
software
to
crash causing
in
memory
file
system
damage.
2.
AMICOD
-
AMI
(application
work
space)
Code.
The number
in
this field
is
used
to identify
an
AMI
(application
work
space)
file
as
belonging
to
a
particular application
program.
Each
application
in
the
system
should
have
a unique
number
in
this
field.
Numbers
in
the
range
0-8FFFh
are reserved
for
use by
Microsoft.
Numbers
in
the
range
8000h-FFFFh
are
for
use by
ISV's
for their
own
applications.
When
an
application
program
terminates, the
O/S
places
this
code
number
into
a
field
in
the
header
of
the
AMI
file.
When
the
application
program
is
reactivated, the
AMI
codes
in
the
application
header
and
the
AMI
header
are
checked
to
ensure
that
the
application actually
owns
the
AMI.
If
an
application
program were
to
be
run using
an
AMI
file
owned
by another
application,
the
result
whould be a system
crash
that
would
almost
certainly
destroy the
machine's
internal
file
system.
This
mechanism
is
a
safeguard
to
help prevent
that
from
occuring.
3.
LDRID
-
Loader
Id
Code.
This
is
used by
the
handheld
operating
system
EXEC
call
to
determine
the type
of
application
being
run,
and
mode
information
about the
exec
being performed.
The LDRID
byte
is
divided
into
two 4
bit
fields.
The
low
order
4
bits
identify
what
type
of
program cod
the application
file
contains.
The
following
values are
defined:
0,1,3
8086
native
code
application
2,4
Microsoft
qCode
application
5
Application
indirection
file
The
high order
4
bits
contain
bit
encoded
mode
information
about
the exec.
The
following
bits
are defined:
1
0h
-
reserved
20h
-
reserved
40h
-
Application
header
contains
optional
fields
80h
-
Use system workspace
file
KJXSYS006.
SYS
as
the
workspace
for this
program.
1.
Bit
40h
-
If
this
bit is
set,
the application
header
contains the
optional
fields
listed
below,
and
their
values
will
be checked
during the
exec
process.
e
114
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