Commodore CBM 2040 User manual

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COMMODORE
CBM
DUAL
DRIVE
FLOPPY
DISK
MODEL
2040
USER
MANUAL
P/N
320830-4
and
is
believed
to
be
entirely
curacies.
The
material
in
this
t
to
change
without
notice.
anual
has
been
reviewed
however,
is
assumed
for
inac
urposes
only,
and
is
subjec
The
information
in
this
m
reliable.
No
responsibility,
manual
is
for
information
p
©Commodore
Business
Machines,
Inc.,
July
1979
“All
rights
reserved."
Commodore
Business
Machines
3330
Scott
Boulevard
Santa
Clara,
California
95050
que
ти
س󰾯
ma
em
n
сле
vh
n
cm
a
—
———
mr
Bán
Й
ұт
B

Table
Of
Contents|
Page No
Section
1:
GENERAL
INFORMATION
.................-
ne
1
DESCRIPTION
ано
Esc
ovd
e
ee
rare
ата
PR
Von
ее
1
Front
Paral
veces
к
ы
iau
yates
ERA
AUS
IO
GER
EO
EFE
Un
eden
1
Back
Panel
Seas
екен
бекет
аннан
enatis
i
ie
ebd
es
ipee
3
Interior
Configuration
.............-ЗеЗеңеееееее
нежен
bos.
3
The
Diskette
«crus
rere
se
een
PU
каакы
Me
НИНА
e
ues
nie
qs
em
dnt
3
Specifications.
лире
ssbb
sd
usi
оне
нение
emu
men
3
CARE
OF
THE
2040
ororo
i
benan
pane
Жа
коньяком
ници
вик
hte
iar
GARE
OF
THE
DISKETTE
ео
exer
eere
Ka
a
качи
Y
никаква
senator
sees
6
UNPACKING
THE
2040
.....................
еее
ТТТ
6
Section
2:
PREPARING
TO
USE
YOUR
2040
.................................??.?“--
9
CONNECTING
THE
2040
TO
THE
СОМРОТЕН...............................???,”?ғ
е”
9
PERFORMING
THE
POWER-ON
TEST
................269ЗЗеЗЗееезеееееезееебеезеееееесееегее:
10
THE
PERFORMANCE
TEST
...............
неее
hme
11
Section
3:
USING
YOUR
2040
................-.----ЗЗЗееебеееебеееезебеееееееееееее-”
15
2040-ASSOCIATED
BASIC
COMMANDS
.....
eee
Án
Mn
16
The
OPEN
Command
............
оне
они
оне
оо
rh
нии
чна
16
The
CLOSE
Command
.................--.
aai
Us
wp
qe
tet
CREDAS
17
The
SAVE
Command
„и
енене
hh
етт.
17
The
VERIFY
Command
„неее
nennen
17
The
LOAD
Command
....................-
2
ббзеееееебезеееееееееее:
usb
en
pa
NE
ae
18
The
РАИМТ#
Command
....-......--...........
4...
а
Eno
PR
УШ
ТЕ
Т
e
18
PREPARING
TO
USE
A
DISKETTE
.................
nn
hehe
19
Preparing
a
Blank
Diskette
......................-.-.--Зеееееееееееееезееееееенееее”
19
Preparing
to
Reuse
an
Old
Diskette
.........
ета
ee
parece
nee
hmm
rnnt
20
Preparing
a
"Currently-In-Use"
Diskette
„...
essent
21
WRITING
A
PROGRAM
TO
A
DISKETTE
1:22
ісікке
ven
ER
ER
EYE
VERI
ERES
EAT
22
READING
A
PROGRAM
FROM
А
DISKETTE
..............
ине
еее
22
DISPLAYING
THE
DISKETTE
DIRECTORY
....
d
ehh
een
23
WORKING
WITH
YOUR
DISKETTE
ҮЙ
ИШКЕ
КУЛТ
Л
Л
ыл
“уы
24
The
VALIDATE
Disk
Command
..............
ehh
25
The
DUPLICATE
Disk
Command
...................5-
ete
25
The
COPY
Disk
Command
„иене
nme
hme
26
The
RENAME
Disk
Command
„неее
26
The
SCRATCH
Disk
Command
.............-.---
езе
енто
венно»
27
DETERMINING
THE
FILE
TYPE
...
ии
еее
неее
28
i
ar apg тсе өч

USING THE DATA CHANNELS рае 28
i The OPEN Command (Complete Version) .............................. Я 28
Closing the Data Channel ео роль аа 29
Glosing the Command Channel „роке A RA RAE RAO 30
Data Transfer to the Diskette ее e EOS ее Gls eee meee Re wT 30
Data Transfer from Diskette ........ rr cer TP 31
| REQUESTING ERROR MESSAGES. ................................................. 31
| Recovering DOS Errors "пе оаа о SN CEP I RES овои 32
SIMPLIFYING THE USE OF 2040-RELATED COMMANDS ........................... 35
Loading the DOS SUPPORT Program eodd toe REESE aW Ina rrr а ақық» 36
Using the DOS SUPPORT Symbols: > and @ .................................... 36
Loading a Program with the / „оаа сао вае реа 37
Loading and Running a Program with $ sS E am du way ded pa баз, — 37
Special DOS SUPPORT information ............................................ 38
Section 4: ADVANCED DISK PROGRAMMING ...................................... 39
DISK OPERATING SYSTEM (DOS)... yx саналаараа оеган аана жааз 39
Special OPEN and CLOSE Statements for Direct Access ......................... 40
DISK UTILITY COMMAND SET Jus xus ооо араа р оока оаа .. 40
The BLOCK-READ Command uso soe ei doo ое анна Бион 42
The BLOCK-WRITE Command «rior ао E E RA ұзына 42
The BLOCK-EXECUTIVE Command ............................................ 43
The BUFFER-POINTER Command 2.42.5 ge er ex XAR ҰБ тыз анта 43
The BLOCK-ALLOCATE Command ............................................. 43
The MEMORY-WRITE Command ............................................... 44
Тһе MEMORY-READ Command :!............................................... 44
The MEMORY-EXECUTE Command ............................................ 44
The USER Command: о dme чове дыз ac каа кыр морате 44
RANDOM ACCESS: EXAMPLE: „а eH зак зы ыы a su ev a aras Rs 45
APPENDICES
APPENDIX A: SUGGESTED READING ......................................... A-1
APPENDIX B: VARIABLE ABBREVIATIONS USED IN COMMAND SYNTAXES ... A-2
APPENDIX C: EXAMPLE PROGRAM — READING & WRITING
SEQUENTIAL -FIEES зама Vale Ka ka X EO Ue RR RR алға ҚЫЗДА A-3

in
Section 1
GENERAL
INFORMATION
With
the
purchase
of
your
Commodore
2040
Dua!
Drive
Floppy
Disk
you
have
greatly
enhanced
the
computing
power
of
your
Commodore
CBM
2001
Series
computer.
This
User
Manual
contains
the
information
you
need
to
connect,
check
out,
and
operate
your
Dual
Drive
Floppy
Disk.
To
get
the
most
out
of
your
system,
you
should
also
consult
your
computer's
User
Manual,
and
if
necessary,
one
of
the
BASIC
manuals
listed
in
Appendix
A.
For
ease
of
reference,
the
Commodore
2040
Dual
Drive
Floppy
Disk
will
be
referred
to
in
this
manual
as
"the
2040."
DESCRIPTION
The
2040,
shown
in
Figure
1,
is
a
dual-drive
diskette
storage
device.
It
consists
of
read/write
control,
drive
motor
electronics,
two
drive
mechanisms,
two
read/write
heads,
track
positioning
mechanisms,
and
removable
diskettes.
The
2040
conforms
to
IEEE-488
interface
requirements.
Because
your
2040
is
an
"intelligent"
peripheral,
it
requires
no
space
in
your
computer's
memory.
This
means
you
have
just
as
much
computer
memory
available
to
you
as
when
you
do
not
have
the
2040
attached.
Front
Panel
The
2040's
front
panel
(Figure
2)
consists
of
an
identification
panel
across
the
top;
slots
in
which
to
insert
two
diskettes;
and
doors
to
close
after
inserting
the
diskettes.
When
you
close
the
door,
the
diskette
is
clamped
onto
the
diskette
spindle
hub.
Also
on
the
front
panels
are
three
LED
indicator
lights.
The
one
on
the
right
is
called
the
Drive
8
Active
Indicator,
and
it
lights
when
Drive
0
is
active.
The
LED
on
the
left
does
thesame
for
Drive
1.
The
indicator
inthe
middle
lights
whenever
a
disk
error
occurs.

Ve ARMATA usn
E + эй “ Ни m зе
MEE Ui oc ЖОЛАЙ
же аы EE қш vut
Tiu
Figure
1.
Model
2040
Dual
Drive
Floppy
Disk
(
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> . : 5

(m
Back
Panel
The
back
of
the
2040
as
shown
in
Figure
3
contains
an
IEEE-488
interface
connector.
Nearthe
рапе!'ѕ
lower
edge
is
the
rocker
switch
for
turning
power
on
and
offto
the
2040.
Thereis
also
a
"slow
blow"
fuse,
and
the
cord
to
the
AC
power
outlet.
interior
Configuration
The
inside
of
your
2040
contains
two
Shugart
390
disk
drives.
All
the
logic
for
your
2040
is
housed
on
the
underside
of
the
lid.
The
mechanical
devices
are,
for
the
most
part,
located
beneath
the
diskettes.
See
Figure
4forasimplified
schematic
of
the
interior
of
your
2040.
(Only
one
disk
drive
is
shown.)
The
Diskette
The
diskette
(also
known
as
à
minifloppy,
floppy
diskette,
minidiskette,
etc.)
is
similar
to
the
standard
flexible
disk.
There
are
several
reputable
manufacturers
ofthe
5%-inch
diskettes.
You
should
make
sure
that
you
buy
diskettes
for
soft
sectored
format.
Your
authorized
Commodore
dealer
can
supply
your
needs.
Figure
5
shows
a
diskette
in
its
jacket.
Specifications
Table
1
contains
the
specifications
tor
the
Commodore
2040
Dual
Drive
Floppy
Disk.
AC POWER
1 6/10А

Table 1
Specifications:
Model
2040
Dual
Drive
Floppy
Disk
Physical:
Material:
18
ga.
steel
Dimensions:
Height
6.5"
Width
15"
Depth
14.35"
Electrical:
Power
requirements:
Voltage
120
VAC
Frequency
60
Hertz
Power
50
watts
IC's:
Controller:
6504
microprocessor
6530
I/O,
RAM,
ROM
6522
1/O,
interval
timers
Interface:
6502
microprocessor
6532
(2)
МО,
RAM,
interval
timers
6332
(2)
ROM
Shared:
6114
(8)
4x1K
RAM
Drives:
Shugart
5А390
(2)
Diskettes
Standard
mini,
54“
Storage:
Total
capacity
176640
bytes
Sequential
170180
bytes
Random
|
170858
bytes
Sectors
per
track
17
to
21
Bytes
per
sector
256
Tracks
35
Blocks
690

Ly 0000 00022009060
Е omang
ЕЕ
LOGIC
CONTROL
ПП
г | READ/WRITE
CONTROL
UNDERSIDE OF LID
INDICATOR
STEPPER
MOTOR LIGHT (LED}
Figure 4. Model 2040: Internal Representation
INSERT INTO DRIVE
WRITE
PROTECT
NOTCH
WHEN COVERED, DISKETTE
CONTENTS CANNOT
BE ALTERED 0902
; змоаойиоо
Figure 5. Position for Diskette Insertion

САВЕ
ОЕ
ТНЕ
2040
Your
2040
should
be
kept
оп
а
flat
surface
free
of
vibration.
It
is
important
that
dust
particles
be
.
кері
аға
minimum
since
а
buildup
of
these
particles
can
interfere
with
optimum
operation.
f
you
should
experience
à
failure
of
the
2040,
contact
your
authorized
Commodore
dealer.
An
attempt
to
correct
the
problem
yourself
could
result
in
the
voiding
of
your
warranty.
CARE
OF
THE
DISKETTES
Your
diskettes
should
be
handled
with
care.
Follow
these
instructions
to
maintain
the
quality
of
your
diskettes
and
protect
the
integrity
of
your
data:
4.
Return
the
diskette
to
its
storage
envelope
whenever
it
is
removed
from
the
disk
drive.
2.
Keep
the
diskettes
away
from
magnetic
fields.
Exposure
to
a
magnetic
field
can
distort
the
data
on
the
disk.
3.
Never
remove
a
diskette
from
its
plastic
jacket.
4.
Do
not
write
on
the
plastic
jacket
with
a
lead
pencil
or
ball-point
pen.
Use
a
felt
tip
pen.
5.
Heat
and
contamination
from
a
carelessly
dropped
tobacco
ash
may
damage
а
disk.
6.
Do
not
expose
diskettes
to
heat
or
sunlight.
7.
Do
not
touch
or
attempt
to
clean
the
diskette
surface.
Abrasions
may
cause
loss
of
stored
data.
UNPACKING
THE
2040
Before
you
unpack
your
2040,
inspect
the
shipping
carton
for
signs
of
external
damage.
if
the
carton
15
damaged,
be
especially
careful
when
inspecting
its
contents.
Carefully
remove
all
packing
material
and
the
contents
of
the
carton.
DO
NOT
discard
any
packing
material
until
you
have
made
sure
you
nave
located
all
the
contents
of
the
carton!
The
package
should
contain:
|
4.
Commodore
Model
2040
Dual
Floppy
Disk
Drive
2.
Model
2040
User
Manual,
Number
320830
3.
TEST/DEMO
Diskette,
P/N
321500
4.
Warranty
card
5.
Miscellaneous
informational
literature

“
.
|f
any
of
these
items
are
missing,
notify
your
Commodore
dealer
immediately.
cable
from
yout
Commodore
dealer
to
connect
Additionally,
you
must
obtain
the
appropriate
ge
9
for
information
about
which
IEEE
cableto
your
2040
to
your
computer.
See
Section
11,
Pa
buy.
ға
Be
мы
ә.
sa
momen,
ыз
EL
XO
ATE
и
СЫСЫ
АРЛЫ,
meh
T
——
олсе
оа
заснето
CAU
n
Mt
O
Da
tn
acm
ب
ر󰾯
ре
E
еа

Section 2
PREPARING
TO
USE
YOUR
2040
Before
starting
to
use
your
2040,
you
should
make
sure
it
is
in
good
working
condition.
This
includes
properly
connecting
it
directly
to
your
computer
or
to
another
IEEE-488
peripheral
device, giving
it
a
power-on
and
initial
checkout,
and
finally
giving
it
a
performance
test
using
the TEST/DEMO
diskette.
CONNECTING THE 2040 TO THE COMPUTER
One of two connector cables is required to connect the 2040 to your computer.
1. PET-to-IEEE cable P/N 320202
Use this cable, if the 2040 is to be the only (or first) IEEE device connected to your computer.
2. IEEE-to-IEEE cable, P/N 905080 |
Use this cable if the 2040 is to be connected ("daisy-chained") to another peripheral device
such as the Commodore Model 2022 or 2023 Printer.
Follow these steps to connect the 2040 to your computer:
1. Turn off the AC power to your computer.
2. Place the 2040 in a convenient location as close as possible to the computer. DO NOT
connect the 2040 to an AC outlet at this time.
3. Connectthe PET-to-IEEE cable between the IEEE-488 interface connector on the computer |
and
the
connector
on
the
2040.
If
additional
IEEE
devices
are
to
be
connected,
the
IEEE-to-
IEEE cable(s) must be used. See Figure 6.
4. Connect the 2040 power cord to an AC outlet. DO NOT turn on power at this time.
2 ^" та "t я PME ЗС Le Ed

Floppy Disk Modei 2040
CBM 2001 Series Computer
IEEE-to-IEEE Cable
(P/N 905080)
PET-to-IEEE Cable
(P/N 320101)
Printer Model 2022 or 2023
Figure 6. Floppy Disk Hookup
PERFORMING THE POWER-ON TEST
You are now ready to proceed with the power-on part of the checkout:
1. Turn on AC power to the computer and verify that it is working correctly.
2. Open both drive doors on the 2040. Make sure that there are no diskettes in either drive. If
you
find
a
diskette,
take
it
out.
:
3. Turn on AC power to the 2040. All three indicator lights (LEDs) on the front panel light -
briefly then go out. If any indicator light remains lit for more than aboutthree seconds, turn
off the power to the 2040. Wait five minutes andtry again. If any light still remains lit, contact
your Commodore dealer immediately.
- 10 -

THE
PERFORMANCE
TEST
When
the
previous
steps
have
been
completed
successfully,
you
may
proceed
with
the
performance
test.
Don't
worry
if
you
don't
fully
understand
exactly
what
is
happening
in
this
test.
All
commands
and
results
are
explained
in
Section
3.
At
this
point,
just
enter
the
commands
by
rote
to
get
a
feel
for
what
you
can
do
with
your
2040.
If
unexpected
results
are
.
obtained
during
any
step
of
the
test,
stop
and
start
over
again.
The
most
likely
cause
ofa
problem
is
an
improperly
entered
command.
This
is
to
be
expected
until
you
become
familiar
with
your
2040.
АН
commands
that
you
type
at
the
keyboard
should
be
followed
by
a
carriage
return:
the
key
on
your
Keyboard.
NOTE:
You
must
enter
the
commands
exactly
as
shown
on
the
instructions
below.
Do
not
insert
any
spaces
in
the
commands
unless
shown
in
the
instructions.
If
the
error
indicator
lights
up,
you
may
be
able
to
continue
the
example
anyway.
Re-enter
your
last
command.
И
the
light
goes
out,
your
correction
was
successful
and
you
may
continue.
à
1.
Insert
the
TEST/DEMO
diskette
into
Drive
8
as
shown
in
Figure
7.
Insert
a
blank
diskette
in
Drive
1.
Remember
to
close
both
drive
doors.
2.
On
the
keyboard,
type:
E
@
+0,
35
Pree pee sit
OPEN
4,845
ЕСЕ”
i
This
command
opens
logical
file
1
on
device
8
(your
2040).
The
secondary
address
of
15
opens
the
command
channel
to
the
2040.
The
screen
displays
your
entry
followed
by
READY.
NOTE
FOR
BUSINESS
KEYBOARD
USERS
ONLY:
if
you
have
a
business
keyboard,
you
may
wish
to
set
your
computer
for
upper
case
character
entry.
You
do
this
by
typing:
POKE 59468,12
and
pressing
the
[RETURN]
key.
Although
it
is
not
absolutely
necessary
to
give
this
command
prior
to
communicating
with
your
2040,
it
does
permit
easy
entry.
In
addition,
the
examples
in
this
manual
can
be
duplicated
exactly
when
you
use
only
upper
case.
|
-11-

Figure
7.
Inserting
the
Diskettes
3. On the keyboard, type:
o equ i
PRINT
41,"
NEWT:TEST,99"
Жағы
PRINT#1
sends
the
command
string
to
the
2040.
It
formats
(soft-sectors)
the
diskette
in
Drive
1,
gives
the
diskette
the
name
TEST,
and
an
ID
of
99.
The
computer
displays
your
entry
and
then
READY.
The
Drive
1
Active
indicator
LED
lights
and
the
drive
motor
runs
for
about
one
minute.
Then
the
motor
stops
and
the
light
goes
out.
. On the keyboard, type:
t=)
<
|
"OL
aL
PRINTH
"ID"
Е
This
command
initializes
Drive
0.
(Drive
1
was
initialized
as
part
of
the
formatting
pro-
cedure
in
number
3).
The
initialization
procedure
places
the
magnetic
head
of
the
drive
in
the
proper
position
above
the
diskette.
The
computer
displays
your
entry,
then
the
word
READY.
The
Drive
9
Active
indicator
lights
up
and
the
Drive
0
motor
runs
briefly.
Then
the
motor
stops
and
the
light
goes
out.
5242»
m

(
5.
On
the
keyboard,
type:
n
d
why
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40
340
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)
|
pa
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нетке
es^
j
Lj
dt
e
£,
2.
^f
LOAD
"5O",B
—
wey
9
42
214
фр"
Ша
t
This command loads the file directory from the TEST/DEMO diskette into the computer's
internal memory.
The computer display now shows:
LOAD "$0",8
SEARCHING FOR $0
LOADING
READY.
At the same time, the Drive 6 indicator lights and the Drive motor runs briefly.
. On the keyboard, type:
LIST
This command requests the display of the TEST/DEMO diskette file directory which
was placed in the computer's memory during step 5. The screen now displays your entry
and the entire file directory for TEST/DEMO.
Notice that the BASIC command LIST involves no interaction with the 2040 since
the directory is retrieved from your computer's memory.
. On the keyboard, type:
LOAD"G:DIAGNOSTIC BOOT",8
This
command
loads
the
Diagnostic
Boot
program
from
the
diskette
in
Drive
@
with
the
computer's
memory.
The computer displays your entry and:
SEARCHING FOR @:DIAGNOSTIC BOOT
LOADING
READY.
Simultaneous
with
the
screen
display,
the
Drive
Ø
indicator
lights
and
the
Drive
0
motor
runs.
Before
going
on
to
step
8,
make
sure
you
remove
the diskettes
when
directed
to
by
the
screen
display.
‚
On
the
keyboard,
type:
RUN
The
program
is
executed.
It
checks
for
malfunctions
іп
I/O
ICs,
RAMs,
and
ROMs.
Follow
the
directions
on
the
screen.
If
all
three
indicators
flicker
continuously,
thetest
is
passed.
If
all
indicators
remain
lit
in a
steady
pattern,
the
directions
оп
the
screen
can
be
used
to
find
the
problem
area.
Contact
your
Commodore
dealer
for
help.
After
30
seconds
of
operation,
reset
the
2040
by turning
the
rocker
switch
on
the
2040
off,
then
back on.
dre

9.
10.
11.
12.
On your keyboard, press:
RUN
STOP
Then
press
the
key
simultaneously
with
the
Rhe
|
key.
Now
return
the
diskettes
to their respective drives.
On the keyboard, type: `
РНІМТЯ 15,410"
LOAD “РЕТ DISK",8
This
program
loads
the
file
containing
the
PET
DISK
program
from
the
diskette
in
Drive
0
to
the
computer's
memory.
The computer displays your entry and:
SEARCHING FOR @:PET DISK
LOADING
READY.
The
Drive
9
motor
runs
simultaneously
with
the
display
shown
above.
On the keyboard, type:
RUN
The
PET
DISK
demonstration
program
is
displayed
continuously
unti!
you
terminate
it.
Notice
that
you
can
hear
the
Drive
0
motor
run
intermittantly
as
one
program
calls
the
next.
On the keyboard, press:
RUN
STOP
Then
press
the[
sHiFT
|кеу
simultaneously
with
the
key.
This
completes
the
Model
2040 Dual Drive Disk performance test.
You
now
know
that
your 2040
works.
You
have
had
a
taste
of
operating
it.
Now
you
are
ready
to
really
make
it
perform.
-14-
алынды санага са tpm

Section 3
USING YOUR 2040
Your
2040 adds
to
your
computing
power
with
added
storage
and
file
handling
capability.
You
control
it
directly
with
BASIC
commands
given
from
the
keyboard,
from
BASIC
statements
within
programs,
and
with
special
disk
commands.
In
this
section
you
will
learn
how
to
apply
these
commands
and
statements
to
the
2040.
The
section
is
organized
in
such
a
way
that
the
functions
and
syntaxes
ofthe
BASIC
commands
andthe
special
disk
commands
are
described
first.
Then
instructions
on
how
to
use
these
commands
to
perform
2040-related
tasks
are
given.
For
the
most
part,
the
instructions
in
this
section
apply
to
program
(PRG)
files
that
contain
BASIC
programs.
Before
you
attempt
to
use
your
2040,
make
sure
you
know
how
to
do
the
following:
1. Operate your Commodore computer
2.
Do
elementary
programming
in
BASIC
3. Open and close files
You
should
refer
to
your
computer's
User
Manual
for
this
information.
This
section
uses
certain
conventions
to
indicate
specific
actions
or
requirements:
Example
Description
dn
italicized
lowercase
letters
in
a
syntax
indicate
that
you
should
enter
something
(a
variable
name)
in
place
of
the
letters.
[i
4
Brackets
indicate
optional
usage.
- 15-

МЕСЕ س󰾯
NOTE: The BASIC statements described in this manual apply specifically to
use with the 2040. Certain of the commands and statements may follow a
stightly different syntax or produce different results from those described here
when they are used for the computer or for other peripheral devices. Consult
the appropriate manual for the exact usage of these commands and statements
in other contexts. ;
2040-ASSOCIATED BASIC COMMANDS
Several BASIC commands that allow you to communicate with and transfer data to and from
your 2040 are described in this section. These commands are:
OPEN VERIFY
CLOSE LOAD
SAVE PRINT#
Let's take а quick look at the syntax of each of these commands and find out what each one
does. Then, in subsequent sections, you will see how to use these commands to perform
certain 2040-related tasks. For more about these commands, and peripheral devices in
general, read Chapter 7 of your computer's User Manual.
The OPEN Command
This command sets up a correspondence between a file number and the 2040. It also opens a
specified channel between the computer and the 2040. The syntax of OPEN is:
OPEN /fn,dn,sa
Where: ип is а logical Не number. You assign this number
arbitrarily and it may be any number between 1
and 255.
dn is the device number. This number must be 8
since that is the number assigned to it at the
factory.
$a is the secondary address. The secondary
address is used to open channels between the
2040 and the computer. At this point, we will
deal with Channel 15 exclusively. Channel 15is
the command and error message channel.
Later, we will explore the use of other second-
ary addresses.
-16-

The
CLOSE
Command
The
CLOSE
command
closes
a
file
opened
by
the
OPEN
command.
Its
syntax
is:
CLOSE ifn
Where:
Ип
is
the
logical
file
number
of
a
file
opened
by
the
OPEN
command.
You
should
always
close
a
file
after
working
with
it.
You
are
not
aliowed
to
have
more
thanten
open
files
in
the
computer
and
five
in
the
2040,
so
it
is
well
to
make
a
habit
of
closing
files
as
soon
as
possible.
This
way
you
will
always
have
the
maximum
number
of
files
available
for
use.
The
SAVE
Command
The
SAVE
command
transfers
programs
from
the
computer’s
memory
to
the
specified
diskette.
SAVE
always
assigns
a
file
type
of
PRG
(for
program)
to
files
that
are
written
to
the
diskette
with
it.
The
syntax
of
SAVE
is:
SAVE
"dr:fn",dn
Where:
dr
is
the
disk
drive
number.
It
must
be
0
or
1.
т
is
any
file
name
of
16
characters
or
less
you
wish
to
assign
to
the
file
to
be
transferred
to
the
diskette.
Blanks
are
counted
as
characters.
dn
is
the
device
number
and
it
must
be
8.
Another
syntax
of
SAVE
is:
SAVE
“@dr:fn”,dn
Where:
@
means
to
replace
the
contents
of
an
existing
diskette
file.
In
is
the
name
of
the
diskette
file
whose
contents
is to be replaced.
The
VERIFY
Command
|
The
VERIFY
command
performs
a
byte-by-byte
comparison
of
the
file
just
written
to
the
diskette
against
the
file
in
the
computer's
memory.
The
syntax
of
the
VERIFY
command
is:
VERIFY "dr:fn",dn
Where:
dr
is
the
same
drive
number
as
used
in
the
imme-
diately
preceding
SAVE
command.
т
is
the
same
file
name
as
used
inthe
immediate-
ly
preceding
SAVE
command.
dn
is
the
device
number,
in
this
case
8.
aie