The Pascal-P compiler was created in 1973, then went through several versions, which so far have not been available. Ch. Jacobi gives an overview of the Pascal-P versions in PUG newsletter #4:
| Name | Origination | Year | Source | Description |
| Pascal P1 | Zurich | 1973 | No | Either of the early Pascal-P systems (released in March and July 1973 respectively) |
| Pascal-P2 | Zurich | 1974 | Yes | The Pascal-P system released in May 74 |
| Pascal-P3 | Zurich | 1976 | No | The new Pascal-P system with the same hypothetical machine as the one underlying the Pascal P2 system |
| Pascal-P4 | Zurich | 1976 | Yes | The new Pascal-P system with a slightly modified hypothetical machine (allowing a more efficient implementation) |
The versions of P1 that existed have (so far) not been available. The revised version, P2, is available, and was used as the basis for the UCSD system. P3 was a “step” implementation used to bridge between P2 and P4, and is also not obtainable.
The last major version of Pascal-P was P4.