SA21-9213-0_IBM_5100aplRef.pdf Page 174 (174 of 232)

168
The variable names to be shared must be established again and the data file
opened. Also, printer output must be specified:

Now, when the function PRINT is executed, the data file is read, displayed, and
printed :
I:' R
1: N '1'
After the operation is complete, the shared variable names should be retracted:
169

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168
The variable names to be shared must be established again and the data file
opened. Also, printer output must be specified:

Now, when the function PRINT is executed, the data file is read, displayed, and
printed :
I:' R
1: N '1'
After the operation is complete, the shared variable names should be retracted:
169

Help

Code Error Message
90
10 0 EXCEEDED MAXIMUM
RECORD LENGTH
11 0 INVALID DATA TYPE
Description and/or User's Response
This return code is only a warning;
an empty vector was read from tape,
but the empty vector is not the
end-of-file empty vector.
This error was probably caused by
the tape being removed before the
file was closed. The remaining data
in the file cannot be read.
The wrong type of data was used;
for example, noncharacter data was
sent to an interchange file, non-
character data was used as the in-
formation required to open a file,
or noncharacter data was sent to
the printer.
AN EXAMPLE USING TAPE AND PRINTER INPUT/OUTPUT
In this example, file number 11 on tape unit 1 will be used as a data file. First,
a variable name must be established to be shared and the data file opened so that
data can be written to the file (OUT operation):
File 11 is an unused file.
I---
0 :1 s.
2
O (I O ') Establish a variable name
1. I::lsUu ' SI-IARE: 'Wt0 be shared.
N- Open the data file.
Check the return code
that was assigned to
the shared variable.
!;HAl?Ec' C1I.J.T' I.(l:lS. :lXl:::( l:NV%3!'T'C)ilY 3 '
s 1-1 A
I? E: --
0 0 'The file was opened
successfully .
166

,
i.
Now, as data is assigned to the shared variable, it is transferred (written) to the
data file:
If more data is to be added to an existing data file but the file is closed, a vari-
able name must be established to be shared and the data file opened again:
Mote: In this example, the variable name SHARE has not been retracted and can
still be shared.
These records are added
following the existing
records in the file.
'' '
Since no more data is to be written on tape, the shared variable should now be
retracted:
I] s v I? ' s 1.i A
RE '
2
167

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Chapter 9. More Things to Know About the 5100
170
DATA SECURITY
You are primarily responsible for the security of any sensitive data. After you
are through using the 5100, the data in the active workspace can be removed by
one of the following:
0 Using the )CLEAR command to clear the active workspace
0 Pressing the RESTART switch
0 Turning the POWER ON/OFF switch to off
There are several methods available for protecting or removing sensitive data on a
tape. These methods are:
0 Assigning a password to the workspace when writ'ing the active workspace on
tape.
Rewriting a tape file, which makes the old data inaccessible.
0 Filling a data file with meaningless data. For example, the following user-
defined function fills file 4, a data file named DATA on tape 1, with zeros:
Mote: ERROR 010 ddd will be displayed after the data file has been filled with
zeros.

5100 STORAGE CAPACITY
The base 5100 (Model All has a storage capacity of 16K (K = 1024 bytes).
Figure 4 shows how this storage is allocated for various requirements. Notice
that the workspace available to the user (active workspace) is 10,600 bytes,
while the remaining bytes are used for internal purposes. The storage capacity
is increased in the following models of the 5100:
Model A2 is 32K
Model A3 is 48K
Model A4 is 64K
In these models, all additional storage is allocated to the active workspace.
For example, on the Model A4, the active workspace is approximately 60,000
bytes.
T-
i
\.-
10,600
Bytes
t 5784 Bytes
L
I
Active Workspace
51 00 Internal Storage Requirements for Pointers,
Counters, etc
I
Note: The symbol table requires eight bytes of storage for
each symbol allowed in the active workspace (see )SYMBOLS
in Chapter 2).
Figure 4. Storage Allocation for a Model A1 5100
171

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