CRCsoft v1.10 by Rolf Aeschbacher

This application does complex checksum calculations on files. Two different CRC (Cyclic Redundancy Checks) are provided to make it extremely secure.

1. The CRC-32 is represented by a 8 digit hexadecimal value (32 bits). CRC-32 is a standard widely used by terminal/filetransfer programs (ZModem) and archivers to check the integrity of data.
The CRC-32 generated by this program is compatible with many popular packers available at present (PkZIP, Arj  etc.).

2. The CCITT-CRC is represented by a 4 digit hexadecimal value. Because the Psion has a routine for this CRC in ROM it is calculated very fast. However it doesn't provide the same security as the CRC-32 because it is only 16 bit wide.

If both CRC values of two files are equal you can be more than 99,9999 % sure that the contents of these files are identical! 
So if you are not sure whether two files are identical you can use this program to check this.
The files may even be on different machines: On most platforms exist tools to calculate the CRC-32 and probably also for the CCITT-CRC. Alternatively you could compress the file using a packer and then use 'view archive' where usually the CRC-32 will also be shown.

Installation: Copy both files CRCsoft.OPO and CRC32.TAB to any \OPO directory. Then select CRCsoft from the list under the RunOpl icon to start the program. If you don't need the CRC-32 you can safely delete the file CRC32.TAB. The menu choice 'CRC32' won't be displayed in this case.
At startup the file CRC32.TAB is checked for integrity using the CCITT-CRC. You will be warned if it failes that check.

After the CRC calculation you are presented with a dialog showing filename(s), CRC, and (depending on the choice) whether the two files are identical or not. On the bottom line you can choose whether this information should be written to a logfile. If this is 'Yes' the file \wrd\CRClog.wrd is opened or created on the default disc, one line is written, and then the file is closed. You can then view this textfile in Word (and optionally import it into a spreadsheet using the 'bring' feature).

Although optimized for speed it takes quite a long time to calculate the CRC32 of larger files. The reason for this is that (apart from the fact that OPL itself is pretty slow) the algorithm requires some bitwise operators which are not present in OPL and therefore must be implemented by several other commands. Use the CCITT-CRC if you need speed.

Disclaimer: This software is Freeware, copyright 1994. You may use it freely but I cannot give any guarantee that it is free of bugs or supply any warranty about its suitability for use.

Rolf Aeschbacher (Zurich, Switzerland)
Compuserve: 100116,3357