ATLAS is an approach for the automatic generation and optimization of numerical software for processors with deep memory hierarchies and pipelined functional units.

Beowulf Project
The Beowulf Project first introduced the concept of a Beowulf cluster.

The BLACS (Basic Linear Algebra Communication Subprograms) project is an ongoing investigation whose purpose is to create a linear algebra oriented message passing interface that may be implemented efficiently and uniformly across a large range of distributed memory platforms.

Linda provides a virtual shared memory (VSM) that is logically shared by all the processes in a parallel program.

MPICH is a freely available, portable implementation of MPI (Message Passing Interface), a message-passing library.

Netlib Repository
Netlib is a collection of mathematical software, papers, and databases.

PVM (Parallel Virtual Machine) is a software system that enables a collection of heterogeneous computers to be used as a coherent and flexible concurrent computational resource. This is a message-passing library.

The ScaLAPACK (or Scalable LAPACK) library includes a subset of LAPACK routines redesigned for distributed memory MIMD parallel computers.