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Note:
You can read only the sectors that fall BEFORE the dam-
aged
sector(s).
All other sectors after the damage cannot be
accessed
.
As a result
,
it would be best to COPY the good files on
the damaged diskette to a new diskette to avoid any further prob-
lems
.
If the file itself is damaged
,
you can also
use
the Get
Byte
pro-
gram to transfer each good sector from the damaged
file into
a
recovery
file.
The A(]TOR(]N.SYS File
When an AUTORUN .SYS file exists on the diskette in Drive
1,
that file will automatically be loaded into
RAM
and executed (if
appropriate) every
time
you boot the system
.
This entire process
is completed before control of the system is returned to you
.
The
AUTORUN .SYS file can be data
;
it can also be object code that is
loaded but not executed
;
or
it
can be object code
that is loaded
and then executed as soon as
the load is
complete
.
The
following sample program shows
the use
of AUTORUN .SYS
to boot up
directly to
DOS
even
if built-in BASIC
or a cartridge is
present
.
After
execution,
AUTORUN .SYS normally returns
to
the
DOS initialization
routine.
If
it does not return during your appli-
cation
,
or if you
use
!
Reset
)
before the return
,
the
system initializa-
tion must be completed before proceeding
.
You can do
this
by
modifying two operating system storage locations: COLDST at
address 244 (hex) and
BOOT
at address 9 (hex)
.
COLDST
should be cleared to 00 and
BOOT
set to 01
.
The
sample program sets these two
locations
to
the proper
value
and then jumps indirectly to the start
DOS
vector.
If
you
do
not
have
an Assembler
Editor
cartridge,
you can create
the equivalent
file using BASIC POKE
statements and
then
sav-
ing the binary file in
DOS. Enter
and RUN the following
:
80
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