(related variations: z1 z2 z3 z3 z4 z5 z6 z7 z8 zco)

A Z-Machine data file. Typically it will represent an interactive fiction story (or interactive tutorial, or similar). It is binary but will work on any machine with some flavor of Z-machine interpreter, and such interpreters are available for virtually every machine in existance (often for free). The 1-4 variants are classic Infocom style; the 5-8 variants are newer. Types 1, 2, 4, 6, and 7 are extremely uncommon; most Z-machine data files are types 3, 5, or 8. Type 8 allows for a much longer, more complex story than the other types -- if types 3 & 5 are viewed as being similar to short stories or novellas, type 8 can be viewed as being as long (or longer) than a full novel. Type 6 provides some graphics support.