IBM 5110 User manual

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IBM 5110
Basic Reference ,Manual ,...
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This manual contains specific information about the IBM
5110 Computer and its BASIC programming capability. Related Publications
IBM 5110 BASIC User's Guide, SA21-9307
Preface
Prerequisite Publication
IBM 5110 BASIC Reference Handbook, GX21-9309
IBM 5110 Customer Support Functions Reference
Manual, SA21-9311
IBM 5110 BASIC Introduction, SA21-9306
First Edition (January 1978)
Changes are continually made to the specifications herein; any such changes will
be reported in subsequent revisions or Technical Newsletters.
Requests for copies of IBM publications should be made to your IBM
representative or the IBM branch office serving your locality.
A Reader's Comment Form is at the back of this publication. If the form has
been removed,
address your comments to I BM Corporation, Publications,
Department 245, Rochester, Minnesota 55901. Comments become the property
of IBM.
© Copyright International Business Machines Corporation 1978
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Contents
l)
CHAPTER 1. OPERATION
Arrays .
61
IBM 5110 Overview Declaring Arrays 62
C~_)
Display Screen 2 Redimensioning Arrays
63
Keyboard 3 Arithmetic Arrays .
63
Special Keys . 7 Character Arrays 64
Switches. 9 Summary
of Naming Conventions 64
Indicators 9 System Functions .
65
Editing Input Lines 10 Expressions
67
Storage Capacity
11
Arithmetic Expressions and Operators.
67
C)
Character Expressions 70
CHAPTER 2. SYSTEM COMMANDS
13
Substring Function
71
Device Address Parameter 14 Concatenation 72
File Reference Parameter 14 Relational Expressions 72
ALERT Command 16 Array Expressions
73
AUTO Command 17 Data Files and Access
Methods.
74
CSKIP Command 19 Stream
I/O Data Files 74
GO Command 20 Record
I/O Files 74
LINK Command.
22 Record I/O File Buffer Requirements
78
LIST Command 23 File FLS
79
LOAD Command 25 National Character Sets 83
Keyboard Generated Data Files 28 Procedure File 84
Function Keys 28
MARK Command' . 31 CHAPTER 4. BASIC STATEMENTS
87
MERGE Command 33 Statement Lines 87
PROC Command 35 Desk Calculator Operations 88
l/' RD= Command 36 BASIC Statement Listing 88
RENUM Command 37 CHAIN.
90
REWIND Command 38
CLOSE.
92
RUN Command . 39 DATA
93
SAVE Command
41
DEF, RETURN, FNEND 95
SKIP Command . 43 Single Line Function 95
UTIL Command . 44 Multiline Function 96
Listing a File Directory 45 DELETE FILE
99
File Types. 47 DIM.
100
Renaming a File on Diskette 48 END.
102
Changing A Diskette Volume ID 49 EXIT 103
Eliminating or Discontinuing a File 50 FNEND 105
Assigning or Removing File Write Protection for Diskette FOR and NEXT 106
Files.
51
FORM 108
Selecting the Diskette Sort Feature . 52 Print Formatting with the FORM Statement 108
Changing the System Default Device Address 52 Record Formatting with the FORM Statement 114
(~,
[MAT] GET.
122
,,---,)
CHAPTER 3. DATA CONSTANTS, VARIABLES, AND GOSUB and RETURN 124
CONCEPTS.
53 GOTO 126
BASIC Character Set 53 IF . 127
Alphabetic Characters.
53 Image 129
Numeric Characters.
53 [MAT]
INPUT.
130
Special Characters 54 LET
132
Cr .. , Use
of Blanks 54 NEXT 134
" Arithmetic Data 55 ONERROR 135
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Arithmetic Data Formats 56 OPEN/OPEN FILE.
137
Arithmetic Constants 58 PAUSE 142
Internal Constants 58 [MAT] PRINT.
143
Internal Variables.
59 Print Zones 144
Arithmetic Variables
59
Spacing of Printed or Displayed Values 144
C)
Character Data 59 Standard Output Formats for Printing or Displaying . 145
Character Constants 60 Display Line Operation 146
Character Variables . 60 Print Line Buffer Operation 150
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[MAT] PRINT USING and Image/FORM . . . . . .
Conversion
of Data Reference Values with Image
Format Specifications
[MAT] PUT .. .
[MAT] READ ... .
[MAT] READ FILE. .
[MAT] REREAD FILE
REM
RESET [FILE]
RESTORE .
RETURN
..
[MAT] REWRITE FILE
STOP
..... .
USE ...... .
[MAT] WRITE FILE
Matrix Operations.
MAT Assignment Statements
MAT Assignment (Scalar Value)
MAT Assignment (Simple) ...
MAT Assignment (Addition and Subtraction)
MAT Assignment (Matrix Multiplication)
MAT Assignment (Scalar Multiplication)
MAT Assignment (Identity Function). .
MAT Assignment (Inverse Function) ..
MAT Assignment (Transpose Function)
MAT Assignment (Ascending Index) .
MAT Assignment (Descending Index) .
CHAPTER 5. MORE INFORMATION ABOUT YOUR
SYSTEM .- ................. .
5110 BASIC Compatibility
with IBM 370/VS BASIC.
BASIC Compatibility with IBM 5100 BASIC
Tape Cartridge Handling and Care .
Storage Considerations
Diskette Handling and Care
Operation
..... "
Handling Defective
Cylinders.
Handling Precautions .
Storage ...... .
Shipping and Receiving
APPENDIX A. 5110 BASIC CHARACTERS AND
153
154
155
160
162
164
166
167
168
170
171
172
174
175
177
178
178
179
181
183
185
187
189
191
193
195
196
197
197
198
199
200
201
201
201
202
206
207
HEXADECIMAL REPRESENTATION 209
APPENDIX B. 5103 PRINTER
How to Insert Forms
Continuous Forms . . . .
Forms Path
for Singlepart Forms
Forms Path
for Multipart Forms
Cut Forms ......... .
How to Adjust the Copy Control Dial for
Forms Thickness . . . . . . . . . . .
How to Replace a Ribbon (Part Number 1136653)
Installing the 5103 Printer Stacker. . . . . . . .
APPENDIX C. 5100 HEXADECIMAL
REPRESENTATIONS ..... ..
APPENDIX D. BASIC ERROR MESSAGES AND
213
214
214
214
214
216
217
217
220
.
.. 221
OPERATOR RECOVERY 223
I/O Errors . . . 224
Execution Errors 227
APPENDIX E. ATTACHING A TV MONITOR 241
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Chapter 1. Operation
IBM 5110 OVERVIEW
... _.'--_. ,-----
The IBM 5110 Model 1 (Figure 1) is a computer designed for direct l;Ise by the
user
for solving problems. The 5110 Model 1 has a display screen, a
combined alphameric and numeric keyboard, a tape unit, switches, and
indicator lights. The 5110 Model 2 is identical
to Model 1 except that it has
no
built-in tape unit. The display screen and indicator lights communicate
information
to the user, and the keyboard and switches allow the user to
control the operations the system will perform. Figure 1 shows a combined
BASIC/ APL 5110.
PROCESS
IN PROCESS
Indicator REVERSE
DISPLAY
Switch BASIC/APL
Switch
Switch DISPLAY
REGISTERS/NORMAL
Switch
Display
Screen
CMD Key
Shift Keys
Figure 1. The IBM 5110 Computer
L ~~:::1.1 JU J.--I-H-.f---- Ar ith metic
EXECUTE Key
Operator
Keys
_. __ ._.".,--._."_ .... ",,,,----------
Operation

2
DISPLAY SCREEN
The display screen (Figure 2) can display 16 lines of data at a time, with up to
64 characters in each line. Input data (information supplied by the user) as well
as output data (processed information) is displayed. The bottom line contains
status information. The number in the lower right (NNNNN) indicates the
number
of character positions (bytes) in storage available to the user.
Line 1 (input line) contains information entered
from the keyboard. The cursor
(flashing horizontal line) indicates where the next input from the keyboard
will
be displayed. If the cursor is moved to a position that already contains a
character, that character flashes, As BASIC processes the input, all lines
of the
display (except the bottom line) are moved up so information can be entered
on line 1 again. The number following
NNNNN in the lower right (001)
identifies the current cursor position relative to the start of the input. This
number
can be up to 896 (14 lines of 64 each).
Line I
~'-------64 Character Positions -------~, I
Numbers __ --------------------------------------------~
15
14
13
12
11
10
9
8
7
6
5
4
3
2
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READY
Figure 2. The 5110 Display Screen Format
NNNNN
Cursor (flashing)
Status Line
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-----_ .. --_. __ ._. __ .-_ .... _ ...
KEYBOARD
The APL/BASIC system keyboard (Figure 3) combines alphameric and numeric
characters. The keyboard provides
two modes of character keying selection:
standard BASIC character mode and lowercase character mode.
When you
turn the system
power on, you are in standard BASIC character mode. In
standard BASIC character mode, you can enter uppercase alphameric
characters (without using the
shift key), the uppercase symbols (using the shift
key), the BASIC statement keywords (on the front of the alphameric keys), and
BASIC commands (above the top row of numeric keys) using the CMD key.
In lowercase character mode, you can enter lowercase (without using the shift
key) and uppercase (using the shift key) alphameric characters, along with the
uppercase symbols (selected using the CMD key). In lowercase character
mode, you cannot select the BASIC statement keywords because the
CMD key
is used
to select uppercase symbols.
To select lowercase character mode, press the HOLD key, then hold
down the
shift key while you press the scroll down'" key. To return to standard BASIC
character mode, press the HOLD key, then hold down the shift key while you
press the scroll up t key.
Operation 3
._------ _._-_._--_.--_._-_._------._-----

4
The following examples show the use of standard BASIC character mode and
lowercase character mode.
In standard BASIC mode, press:
to enter the character K.
to enter the charaacter ' (single quotation mark).
to enter the keyword PAUSE.
In lowercase character mode, press:
to enter the character k.
to enter the character K.
to enter the character' (single quotation mark).
Note: All the examples in this manual are in standard BASIC character mode.
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You can enter numeric data conveniently by using the calculator arrangement of numeric
keys
to the right of the alphameric keys. You can also enter this data by using the
numeric keys above the alphameric keys. The arithmetic operator keys, located on the
right of the keyboard, are also on the alphameric keys.
Note
that on a BASIC-only keyboard (Figure 4) upper shift APL symbols above the
alphameric characters can be entered as data, even though they do not appear on the
BASIC keyboard.
When
any of the keys are pressed, the characters entered appear in the input line on
the display screen.
BASIC statement keywords are printed on the front of the alphameric keys. These
words are entered starting at the current cursor position when the CMD key is held
down and the corresponding key is pressed (in standard BASIC character mode).
Operation 5

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QJCDCDCDCDCO(I)OJCDCD~O CJGJ80
CO CO CD GJ CD CD CJ [J (I) CD OJ CD [J GJ GJ [?-
_ GJCDCIJwCDCDITJ[]CJCDCIJ _ OCJD 0
( 0 )0 []
Figure 3. Combined BASI,C/APL Keyboard
[] [J CD CD OJ CD CD OJ GJ [J CJ 0 •• ••• .:---~:
CD GJGJGJ GJCOGJCJGJCDOO CJGJ8 CJ
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Q GJ [J GJ GJ GJ [J [J [J CD OJ CD [J GJ GJ 0
- GJGJGJGJGJGJITJ[]CJQCIJ _ OCJD 0
( ( 0 )0 []
Figure 4. BASIC-Only Keyboard
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Special Keys
The following keys have special functions relating to system operations:
•
-
(Attention)-You can press the ATTN Key to stop system
operations. While you are entering data
at the keyboard, you can
press the ATTN key
to blank everything from, and including, the
cursor position
to the right on the input line of the display
screen.
If the display is in use as an input device, the ATTN key
will blank everything
to the right and below the cursor position.
You can then continue entering information. In addition, the
ATTN key and the HOLD key are the only keys that are active
when the display screen flashes
to indicate detection of an error.
After you press the ATTN key to stop the flashing display
screen, all keys are active and you can proceed. The ATTN key
must also be used (after the audible alarm has sounded)
to
resume procedure file operations.
(Command)-When you hold
down the CMD key, you activate the
top row of alphameric keys, which cause the command keyword
to be inserted on the input line when the number below the
word is also pressed. The command operation is executed when
you press the EXECUTE key. The CMD key is also used with
the numeric keys (on the right side of the keyboard) to initiate
keys functions. Avoid holding down the
CMD key and pressing
the HOLD key; this activates a function restricted
to use by
service personnel. Holding
down the CM0 key (in standard
BASIC character mode) and pressing a key with a BASIC
statement keyword on the front will enter the keyword beginning
at the current position
of the cursor. In lowercase character
mode, the CM0 key·allows you
to type in the uppercase
symbols.
When you press the EXECUTE key, the system processes the
line of data that you just entered on the input line. In addition,
you can press the EXECUTE key to resume interrupted
processing. Pressing the EXECUTE key when the
input line is
blank causes the same action
as a GO command (see GO
Command in Chapter 2).
When you press the HOLD key, all processing stops. Processing
resumes when you press the HOLD key a second time. Thus,
the HOLD key allows you
to read displayed data during an
output operation. While processing is stopped, the CMD key
and the arithmetic operator keys
on the right of the keyboard are
restricted
to use by service personnel. The HOLD key also
allows you to change from standard BASIC character mode to
lowercase character mode and vice versa. See National Character
Sets in Chapter 3.
(Shift)-While you hold down a shift key, you can select an
uppercase symbol (in standard BASIC character mode) or an
uppercase alphameric
(in lowercase character mode) for input.
Operation 7
---_ .. _-------_._--------

8
o (Copy Display-when the CMD key is held
down)-When you hold
down the CMD key and press the key below Copy Display, all
data displayed on the screen is printed by the attached printer.
You can use the copy display function when the system is in a
hold state, or anytime the system is waiting for input from the
keyboard.
On a combined BASIC/ APL machine, the CD key is used
to activate the copy display function. The L32 64 R32 switch
has no affect on printed data.
The following keys have a repeat capability, which means that they will
continue
to function for as long as they are pressed:
•
•
•
(Backspace)-When you press this key, the cursor moves one
position
to the left. When backspaced from position 1 of the
input area, the cursor moves
to the rightmost position of the
input area. When you hold dm"m the CMD key and press this
key, you immediately delete the character at the current cursor
position. All characters
to the right of the cursor are shifted one
po'sition
to the left each time you press this key. The cursor
does not move.
(Forward Space)-When you press this key, the cursor moves one
position to the right. When spaced beyond the end of the input
area, the cursor returns
to the first position of the input area.
When you hold
down the CMD key and press this key, you
immediately insert a blank character at the current cursor
position, and all data following the cursor position is shifted one
position
to the right. The cursor does not move; thus you can
enter another character into this position. If the input area
contains a character
in the last position, the insert function is
ignored.
(Scroll Up)-When you press this key, each displayed line moves
up one line position (except the status line). This key also allows
you to change from lowercase character mode to standard
BASIC character mode (when used with the'HOLD and shift
keys). When the keyboard is open and the cursor is displayed
on one
of the top 14 lines, the scroll up key moves the cUrsor up
one line.
(Scroll
Down)-When you press this key, each displayed line
moves down one line position (except the status line). This key
also allows you to change from standard BASIC character mode
to lowercase character mode (when used
with HOLD and shift).
When the keyboard is open and the cursor is displayed on one
of the top 14 lines, the scroll down key moves the cursor down
one line.
Note: The spacebar also has repeat capability. Blanks are inserted if you hold
down the spacebar.
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SWITCHES
The following swtiches are located above the keyboard on the console:
POWER
ON/OFF -The power switch turns the system on and off. When
power is turned on, the system ~ecomes operable in approximately 10-15
seconds.
RESTART -This is a spring-returned switch that reinitializes the system to
its power on state. In the dual language system, the setting of the
BASIC/ APL switch determines which language is initialized.
BASIC/ APL -This switch appears only on the dual language system and
determines which language is initialized at power on and restart.
REVERSE DISPLAY -This two-position switch sets the display screen to
white characters on a black background or to black characters on a white
background. You may want to adjust the BRIGHTNESS switch after setting
the
REVERSE DISPLAY switch.
BRIGHTNESS -This control varies the intensity of the characters or the
screen background.
DISPLAY REGISTERS/NORMAL -This switch is for use by service
personnel. This switch should remain in the NORMAL position during
system operation.
L32
64 R32 -The three positions of this switch are:
L32 The
leftmost 32 characters on the display screen are displayed with
a blank between characters.
64 Up to 64 characters per line are displayed in adjacent positions.
R32 The rightmost 32 characters on the display screen are displayed
with a blank between characters.
INDICATORS
The console has two indicators:
PROCESS CH ECK - When this indicator lights, a system malfunction has
been detected, and further operations are not normally possible. Press the
RESTART key. If the condition recurs, call for service.
IN PROCESS -This indicator lights only to inform you that the system is
operating even though
the display screen is turned off. Because some
programs require several minutes
of processing that turns off the display,
the IN PROCESS indicator is
your assurance that the system is operating.
When this indicator light is on, the HOLD key does not stop processing.
._----- -------_. __ . -_ .. _- ... __ ._---------_.
Operation 9

10
EDITING INPUT LINES
If you detect an error in a line before you press the EXECUTE key to enter the
line into the system, you can use the forward space or backspace key to
position the cursor at the error, then:
• You can use the insert or delete functions to correct the error.
• You can press the ATTN key to blank all data to the right of the cursor.
• You can enter the correct character. Note that the APL symbols (upper shift
on several keys) in Figure 3 can be entered into an input line. On a
BASIC-only keyboard (Figure 4), however, these symbols do not appear
even though they can be entered into
an input line. Because many of these
symbols can be overstruck
by other characters (such as ' and . to create !)
you can take the following steps to replace an APL symbol:
1. Position the cursor at the symbol.
2. Press the spacebar to erase the symbol.
3. Backspace the cursor
to the blank position.
4. Enter the correct character.
If you detect an error in a line after you press the EXECUTE key to enter the
line, you can use the scroll up
or scroll down key to position the line to be
corrected, then use the procedures above
to correct the error.
If you want to change an entire line, you can simply enter the statement
number
of the line, then reenter the line and press the EXECUTE key. The new
line will replace the old line.
If you want to delete one or more program lines, enter the statment number of
the line you want to delete, then enter DEL and press the EXECUTE key. To
delete several
succE~ssive lines, enter the number of the first line, enter DEL,
enter the number of the last line, then press the EXECUTE key. For example,
to delete lines 20 through 90 in a program, enter:·
20 DEL 90
then press the EXECUTE key. Note the DEL is invalid while you are entering a
key group (see Function Keys).

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STORAGE CAPACITY
The base system (Model 811 or 821) has a storage capacity of 16K (K=1,024
bytes). Figure 5 shows
how this storage is allocated to various requirements.
Note that the
work area available to the user is approximately 1'1,500 bytes,
while 4,500 bytes are required
for internal purposes. The storage capacity is
increased in the following models of the system (the first digit represents
model number 1
or 2, and the second digit represents storage size):
Model
812 and 822 - 32K
Model 813 and 823 - 48K
Model 814 and 824 - 64K
In these models, all additional storage is allocated to the user work area. For
example, on the Model 814, the user
work area is approximately 59,500 bytes,
.
with the remaining 4,500 bytes used for internal purposes.
11,500 8ytes
User Work Area
(data and programs)
I- - - - - - - - - - - - - - - - - - - - -- -
4,5008ytes
(internal system requirements)
Figure 5. Storage Allocation for a 16K System
Operation 11
--------------_._----_.-

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Chapter 2. System Commands
Some of the system commands are listed above the top row of numeric keys
on the
typewriter-like alphameric keyboard (Figure 4). These commands allow
you to control diskette, tape, and printer operations, such as storing a program,
loading a program into the system, and executing a loaded program. System
commands can either be entered character-by-character from the keyboard, or
the entire keyword can be entered by holding down the CMD key and pressing
the appropriate number key
below the command (except for those, such as
LINK and MERGE,
that are not listed). The latter operation inserts the keyword
with a single keystroke, thus preventing possible keying errors and providing
faster operation. The commands are used
to direct the system to perform the
following types of operations:
• Program Execution-Start or resume execution of a BASIC program or
command.
• File Operation-Load or save programs or data on tape, or diskette, or mark
tapes/ diskettes.
• Program Operation-List and number program statements or merge several
programs into one program.
Parameters required for a command can be entered after the command
keyword is entered. The command operation then starts
after you press the
EXECUTE key. The command keywords and major functions of the BASIC
system commands are:
ALERT
AUTO
CSKIP
GO
LINK
LIST
LOAD
MARK
MERGE
PROC
RD=
RENUM
REWIND
RUN
SAVE
SKIP
UTIL
Alert the operator
from a procedure file
Automatic line numbering
Skip within a procedure file on a specified condition
Resume interrupted processing
Load customer support functions, features, or IMFs
Display or
print a BASIC program
Load a BASIC program
Mark tape/ diskette files
Merge a BASIC program
Initiate input from a procedure file
Specify rounding position
of printed numeric values
Renumber statements
Rewind tape
Run a BASIC program
Save a BASIC program
Unconditionally skip records within a procedure file
Perform system support functions
System Commands 13
------- ----.- ...... ". __ ...... " ... "._-._. __ .. _.....

14
DEVICE ADDRESS PARAMETER
Many BASIC commands and statements require entry of a device address
parameter.
This address identifies
the input/output device containing the file being
processed. Valid device addresses
for the 5110 are:
E80 - for the built-in tape unit (Model 1 only)
E40 -
for the auxiliary tape unit (Model 1 only)
080 - for diskette drive 1
040 - for diskette drive 2
020 - for diskette drive 3
010 - for diskette drive 4
500 - for the printer
000 - for directing output to line 1 of the display
screen (output only)
001 - for allowing GET statements to access data entered
from the keyboard (in the same manner
that INPUT
statements receive data)
002 - for allowing up to 14 lines of the display
screen to be used as keyboard input, output, or
update
as a record file
Note: The normal system default address on the 5110 Model 1 is device E80.
The normal system default address on the 5110 Model 2 is device 080. These
defaults can be changed with the UTIL SYS command, which allows you to
select the default address you want to use (see UTIL Command). If you do not
enter a device address
with commands, the default address will be used. You
can also enter
'SYS' for the device address parameter in the OPEN [FILE] and
CHAIN statements to specify the system default device address.
FILE REFERENCE PARAMETER
The file reference parameter in many BASIC commands and statements can
consist
of either the file number or the file name, or both the file number and
name. File names can be
of the following types:
• For any files on tape, the file name can be any combination of up to 17
characters.
For files
on diskette, the file name can be either simple or complex. Simple
file names can be
from 1 to 8 characters in length. The first character must
be
an uppercase alphabetic character (A-Z). The remaining characters can
be alphanumeric (A-Z or 0-9). Blanks are not permitted. A simple file name
must be used when creating basic exchange diskette files (see Customer
Support Functions Reference Manual for information on basic exchange files).
• Complex file names can be two or more simple names separated by a
period. Total length
of a complex file name is 17 characters including the
period separator(s).
As with simple file names, blanks are not permitted
within complex file names.
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When you enter a file name, be sure to enclose it in single quotation marks. If
you enter both the nonzero file number and file name for a diskette file, the
system accesses the file
by name, but also compares the number you specify
with the number of the file accessed. If the file number and name do not
match, an error message is displayed.
Note: When a file is being accessed for output, an error will occur unless the
file is unused (type 0)' or unless the file name you specified matches the
existing file name. See UTiL
for information on making a file unused or
changing a file name.
The syntax and description
of each command is detailed in this section. Note
that the syntax used in BASIC commands is also used for the BASIC
statements (Chapter 4). In this syntax, parameters that must be specified as
shown are in uppercase letters. Parameters you must supply are in lowercase
letters. Optional parameters are enclosed in brackets
([ ]). Parameters
enclosed
in braces ({}) indicate that you must enter only one of the
enclosed parameters. Ellipses (...) indicate that the preceding parameters
can be repeated. Single quotation marks and parentheses must be entered
where shown. Commas must be entered to separate parameters, except
between the keyword and the first parameter.
Each command or statement entered from the keyboard
is checked for
syntax errors.
If a syntax error is detected, an up arrow (t) is displayed
below the position in the line where the error was detected, the optional
audible alarm sounds, the display screen flashes, and the keyboard is locked.
The ATTN key and HOLD key are the only active keys when the display screen
flashes. Press ATTN to stop the flashing screen, then correct the indicated
error.
Some general rules that apply to system commands are:
• No preceding statement number is needed.
• Each command must begin a new line.
• Maximum command length is 64 characters.
• Blanks are ignored except in character strings enclosed in single quotation
marks.
• Parameters must be separated by a comma.
System Commands 15

16
ALERT E:ommentJ
ALERT COMMAND
The ALERT command allows you to provide an indication to the operator that
intervention is needed during the execution of a procedure file (see Procedure
File). When executed, the ALERT command halts system operation, sounds
an
audible alarm, and causes the display screen to flash the word ALERT and the
optional comment. The operator must press the ATTN key tostop the flashing
screen. The optional comment can be an instruction to change tapes or
diskettes or perform other necessary operations. Comment length is limited
only by line length. To resume normal operation, the operator can enter
GO.
To terminate operation, the operator can enter GO END.
The ALERT command can only be entered in a procedure file.
Examl?ie
The following is a typical ALERT command.
ALERT REPLACE RECEIVABLES DISKETTE
WITH PAYABLES DISKETTE
When this command is executed in a procedure file, the associated message
will be flashed on the screen to instruct the operator to change diskettes.
(-_.""",
.
..... - ......
'-