Chexsum

File Format
Name	Chexsum
Ontology	Electronic File Formats Error detection and correction Chexsum
Released	1983

Chexsum is a type-in program checker for the Commodore 64 and 16, Amstrad CPC 464 and 664, Atari 130XE, and MSX used by Melbourne House Publishers.

It displays a four-digit checksum for each entered line based on the tokenized BASIC, so it ignores extraneous spaces, REM statements, etc.

It can sometimes see a '.' as a ',' and a ';' as a ':' or even a '9' as a ')' if they fall on certain positions in a program line.

There are different versions in each book.

Sample Output

Links

• Let's Type Castle of Doom (1983) – The Strangest C64 Game I've Typed In - demonstration of the program in use at 2:12 and 8:25, also a mod to make it automatically pause every 10 lines
• Commodore 64 Games Book pg 4 (alternate source)
• Commodore 64 Games Book 2 pg 7 (alternate source)
• Commodore 64 Machine Language for the Absolute Beginner pg 176
• Commodore 16 Games Book pg 16
• C16 PRG file
• MSX Games Book pg 6
• Amstrad Games Book pg 3
• Writing Adventure Games on the Amstrad pg 155 (alternate source)
• Atari 130XE Games Book pg 3 (alternate source)
  • .ATR file (source page)