The CRYSNET terminal organization

Abstract

The CRYSNET terminals are intelligent remote graphics terminals forming a network for crystallographic computing. These terminals are assembled from commercially available hardware and use software written largely in FORTRAN. They provide high performance graphics, local computation, remote batch job submission, and remote interactive use of a variety of central sites. Each terminal consists of a DEC PDP 11/40, 28k of 16 bit memory, Vector General 3-D display, single platter removable disc drive, card reader, printer/plotter, magnetic tape drive, 2000 baud synchronous interface to the phone lines. The current price for such a system is now about $100k. The current software supports display of molecular models in several forms, plotting, and crystallographic computations sufficient to have a noticeable impact on the time needed for structure solution and analysis. The terminal provides a collection of useful tools to which its users constantly add new code. The user does not have all the power he would get from a system interfaced to a very large computer, directly, or via high band width lines. The user also does not have the special features to be gained from hardware specifically engineered for the task. For example, black boxes to computer inter-molecular contacts will probably be the best way to do such a job for some time. However, it appears that the user has enough power and features for the current application. The equipment is in a reasonable price range and, being off the shelf, is available to a moderately large community with maintenance a controllable if not fully solved, problem. Since the terminal is based on a general purpose mini-computer, the user also has a great deal of flexibility in his use of the terminal. The computer supports a disc operating system with FORTRAN compiler. Thus, many users can write new code for their own applications. This has allowed a great deal of software to be developed at very low visible cost.