I very much doubt you'll be able to download Oracle 7 from anywhere now. It is still available from Oracle to my knowledge, but they don't normally give anything for free.

There are massive differences between Personal Oracle 7 and 8i, but providing you don't try and use them, then you should have no problems with compatibility.

The only thing you would have problems with is trying to run forms 6i at home and 4.5 at Uni.

Terry