| The really useless ROM Basic in old TRS-80 Model I computers. It only gave you 26 numric variables, A-Z, two string variables A$ and B$ up to 16 characters long each, and one array variable (named A, of course) that could have as many elements as you had RAM for. Unlike newer BASIC dialects, Level I Basic required line numbers on every line.
Only 3 error messages exist in LeveL I Basic: WHAT? for syntax errors, HOW? for any other programmer error, and SORRY for computer errors (like running out of memory).
Level I Basic was eventually replaced (via ROM upgrade) to Level II Basic, which had many more features, variables and more informative cryptic error messages, not to mention some cool games that I want to translate to C if i ever get any free time. | 
