As programmers know, the higher level language in which people write programs must have perfect syntax and grammar. Computers are unforgiving - there is no room for irregular verbs or misspellings with them. In both ADS and Unicorn there were a significant number of misspellings in the comments. The words appeared in identical comments in both programs - or more specifically, they appeared in different programs within each suite of programs. Moreover, each of the words was correctly spelt in a number of different places in other parts of the program.
Comment headings Identical comment headings occurred in both programs.
For instance, the word 'FORD' was presented in a comment in both programs with 23 hyphens to the left and 30 to the right. The manufacturers in the corresponding programs were listed in identical, not quite alphabetical order. Also, the last two manufacturers had a hyphen missing at the end in both sets of programs. Computer clock A certain unused format program, part of the original ADS, was also found in the Unicorn source code in a number of places but commented out. The explanation offered was that it may have been copied accidentally when customers' data files were transferred.