Terminal emulation programs

Application layer The seventh, or highest, layer in the International Organization for Standardization s Open Systems Interconnection (ISO/OSI) model for computer-to-computer communications. This layer uses services provided by the lower layers, but is completely insulated from the details of the network hardware. It describes how application programs interact with the network operating system, including database management, e-mail, and terminal emulation programs. 

The advent of personal computers and terminal emulation programs has reduced the cost of high quality graphics displays by almost an order of magnitude and probably the majority of users of these public systems now use this type of equipment. 

Figure 1. Terminal Emulation Programs. No graphics emulation...

Figure 2. Terminal Emulation Programs. Graphics emulation (Tektronix 4010/4014)...

PC as terminal. The PC can be used as a terminal to another multi-user computer system, the host. For this purpose an emulation program is needed for the PC to... 

ChemSketch is a software program developed in-house to draw chemical structures and to retrieve structures from MACCS. It is written in VAX C and will run on any of the VAX CPUs as long as they are running the VMS operating system. ChemSketch currently supports Tektronix 401x, VT-640, and VT-240 terminal emulation. 

Both the terminal emulation and the structure drawing programs offer multiple windows (to build two or more structure queries, or connect to two hosts, while also browsing a transcript). 

To make the Macintosh compatible with MACCS, we use the Versaterm Pro software package, which allows the Macintosh to emulate the Tektronix 4105, one of the acceptable terminal types. By this same package, the Macintosh can emulate the Tektronix 4014 and VT-100, which allow the chemists to use other applications programs, such as SYNLIB for chemical reaction literature and of course, all the standard non-graphics applications such as electronic mail. 

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