This covers a number of classic mainframe systems, such as PDP-11, DEC-20 and VAX-11.
| Title | Publisher | Year | Language | Documents |
|---|---|---|---|---|
| Xeno | Jonathan Mestel | 1989 | English | Solution, SLAG hints |
| Xerb | Andrew Lipson | ? | English | |
| Zork | Bruce Daniels, Dave Lebling, Marc Blank, Tim Anderson | 1977 | English | |
| Zork I: The Great Underground Empire | Infocom |
1980 | English | Solution, SLAG hints, Map |