TANGRAM-II is a modeling environment developed for research and educat
ional purposes that provides a flexible user interface to describe com
puter and communication system models. It is based on an object orient
ed description language and has a sophisticated graphic interface buil
t from the public domain software package TGIF (TANGRAM Graphic Interf
ace Facility). The current version is implemented in C++ and C and has
several solvers for transient and steady state analysis of performanc
e and availability metrics. Several examples that we present highlight
the modeling capabilities of the environment. (C) 1998 Published by E
lsevier Science B.V. All rights reserved.