unary
Explanation
The Joke
The comic opens with the narrator musing about what the scariest thing a manager could say to a programmer would be. The manager then announces: "Wait a minute -- all numbers can be specified using a unary numeral system, but we are using zeroes and ones on all of our computers!"
The horror here is that the manager has just enough knowledge to be dangerous. A unary numeral system represents numbers using only one symbol (like tally marks), so the number 5 would be written as "11111." The manager is technically correct that any number can be represented in unary, but implementing this on actual computers would be catastrophically impractical -- storage requirements would explode exponentially, and all of modern computing relies on the efficiency of binary representation.
The Humor
The joke plays on the well-known fear programmers have of managers who learn just enough about a technical concept to propose a terrible, sweeping change. The specific terror is that the manager has identified something that is technically true (unary works in theory) but would be an absolute disaster in practice. The programmer"s horrified expression captures the dread of being told to re-architect every computer system based on a fundamental misunderstanding of why binary was chosen in the first place.
References
A unary numeral system uses a single symbol to represent natural numbers, where the number N is represented by N repetitions of that symbol. While mathematically valid, it is wildly inefficient compared to binary (base-2), which is the foundation of all modern digital computing. Binary was chosen for computers because transistors naturally have two states (on/off), making base-2 the optimal encoding.