Algorithms are designed to implement molecular-dynamics simulations on emerging concurrent architectures. For systems with finite-range interactions, a domain decomposition algorithm is used to implement the multiple-time-step (MTS) approach to molecular-dynamics (MD) simulations on distributed-memory multiple instructions multiple data (MIMD) machines. This approach reduces the computation of forces significantly by exploiting the different time scales for short-range and intermediate-range interactions. Parallel algorithms are also designed for MD simulations of bulk Coulombic systems. The performance of these algorithms is tested on the Intel iPSC/860 system. The computational complexity of these algorithms is O(N) and parallel efficiencies close to 0.9. Molecular-dynamics simulations are carried out to investigate the structural and dynamical properties of highly densified and also porous silica glasses. Changes in the short-range and intermediate-range order in amorphous SiO2 are determined at different densities in the range of 4.28-0.1 g/cm3. Results for internal surface area and surface-to-volume ratio in porous SiO2 are also discussed. © 1993 John Wiley & Sons, Inc.