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