Algorithms are described that help with obtaining a classification of the semisimple subalgebras of a given semisimple Lie algebra, up to linear equivalence. The algorithms have been used to obtain classifications of the semisimple subalgebras of the simple 8. These have been made available as Lie algebras of ranks a database inside the SLA package of GAP 4. The subalgebras in this database are explicitly given, as well as the inclusion relations among them.