Future releases of the ScaLAPACK library will extend the flexibility of the PBLAS and increase the functionality of the library to include routines for the solution of general banded linear systems, general and symmetric positive definite tridiagonal systems, rank-deficient linear least squares problems, generalized linear least squares problems, and the singular value decomposition. Finally, general sparse and out-of-core prototype routines are being investigated, as well as an HPF [23, 25] interface for the ScaLAPACK library. An extensive discussion of alternative approaches for scalable parallel software libraries of the future can be found in [8].