Category : Modula II Source Code
Archive   : CRC-M2.ZIP
Filename : CRC.DOC

Output of file : CRC.DOC contained in archive : CRC-M2.ZIP
July 12, 1989

CRC-M2 - Cyclic Redundancy Checker, Version 1.00 - This tiny CRC
program accepts wildcards and multiple filespecs from the
command line. This is a free program. Displays same CRC values
as PKPAK and LHarc. JPI TopSpeed Modula-2 source code included.

Program background
Other programs
Closing remarks

This program is actually a by-product of my search for an
efficient and reliable CRC algorithm. What prompted this search
was my desire to write my own file concatenation program, and
CRC values would provide assurance of the integrity of the files

Just specify the names of the files to check after the program

Usage: CRC filespec [filespec ...]

Examples: CRC *.exe *.com
CRC \autoexec.bat
CRC d:123*.* filename.ext *.e?e

Program background:
I used two sources as my starting point in writing this program.

The first was the Turbo C source code for a very tiny CRC
program written by John Bridges. The routine he used to compute
CRC values was written in in-line assembly language. This
routine I translated and adapted to Modula-2.

Whereas Mr. Bridges used a table of values in his program to be
used in the computation, I found a routine in the source code of
LHarc V1.13b which builds the table from the ground up. This
routine was written in assembly language. This I also
re-implemented in Modula-2.

In contrast to my use of the high-level language Modula-2 to
implement the essential CRC calculation, I've written my own
simple screen-writing and file-handling routines which use DOS
calls. This is made convenient by a library routine included in
the default TopSpeed library. I did this mainly to remain true
to Mr. Bridges' original goal of trying to make the smallest CRC
utility while still using high-level language (in his case Turbo

Other programs:
Other free programs which I have written and contributed to the
Public Domain:

CAL - Calendar V1.00 - 06/03/89 - A simple, stand-alone calendar
dislay program that can be used as a sort of perpetual calendar.
Valid years range from 0001 to 9999. This program is NOT
memory-resident. Scroll through the different months and years.
Source code included.

DIRDEL - Directory Delete V1.23 - 05/01/89 - Delete any
subdirectory, whether empty or containing files and other
directories. Delete directories containing read-only, hidden
and system files and directories. Even delete the current
directory. (Source NOT included.)

FIX - File Fix V2.15 - 05/16/89 - View and edit any type of
file, text or binary, read-only, hidden or system. Edit in
ASCII or hex. Useful for working with simple, random-record
files. Select files from a scrollable, pop-up directory window
- less typing required! (Source NOT included.)

FFIND - File Finder V1.05 - 06/16/89 - A simple program to find
any file or subdirectory. Although the size of the executable
file is a little larger than that of the competition and
although there are no command-line switches, this little utility
is also often a little faster, is free - and the source code is

All the above program were written in JPI TopSpeed Modula-2.

Closing remarks:
Interested users are encouraged to contact me with comments, bug
reports, suggestions and questions about the program. I can be
reached at the addresses below:

By conventional mail:
Raymond T. Kaya
P. O. Box 1436
Honolulu, HI 96806

By electronic mail:
CompuServe: 71230,2500
GEnie: R.KAYA1

  3 Responses to “Category : Modula II Source Code
Archive   : CRC-M2.ZIP
Filename : CRC.DOC

  1. Very nice! Thank you for this wonderful archive. I wonder why I found it only now. Long live the BBS file archives!

  2. This is so awesome! 😀 I’d be cool if you could download an entire archive of this at once, though.

  3. But one thing that puzzles me is the “mtswslnkmcjklsdlsbdmMICROSOFT” string. There is an article about it here. It is definitely worth a read: