General purpose parallel Fortran subroutines are presented for the solution of sparse and dense symmetric systems of linear equations. They constitute an efficient tool that can be easily implemented on already existing sequential out-of-core direct solvers. They are designed to run on the whole class of multiprocessors with local and/or shared memory. Numerical experiments are carried out on both Intel Personal Super Computer (local memory) and Encore Multimax (shared memory). The impact of hardware architecture on software implementation and performance is discussed. Important issues for the efficient use of parallel computers are addressed.