Intro

There are five pertinent structures that will be reviewed in relation to EIES: one at the FORTRAN system level, three detailing EIES at the internal system level, and the menu structure at the external level. The FORTRAN structure is at the lowest level, and describes how data is processed within the system. The internal system structures describe the routines and procedures of EIES, the code implementation on top of the system. The menu structure refers to the cascading CHOICE system that the user navigates, the user interface that is functionally on top of the internal structure. This methodology is demonstrated on the EIES Simulator.

The FORTRAN structure and two EIES structures were found in a box with research reports, and have no discernible markings that would allow us to cite them; therefore, the closest credit we can give is to Ellen Lieberman for finding the box. The Internal system structure was drawn by Martin Lyons while he worked at the CCCC, and is used with his permission. The UI structure is in actuality a user guide that was given to all new users, so there is no one source to cite, besides the CCCC.

Structure #1: FORTRAN Level

This diagram basically explains the logic flow for compilation of FORTRAN and the additional FLECS (FORTRAN Language with Extended Control Structures). Keep in mind, FORTRAN was an early higher-level language, so FLECS was only an extension of it. The Hierarchical system is very simplistic, code developed in FLECS is integrated into the source and compiled, where it meets up with the code written direcly in FORTRAN and is optimized using the Post-Processor Optimizer. This is eventually assembled and transferred to the object. The offshoots along the way are for error handling and logging that could possibly come up, but are not part of the normal operation.

Structure #2: EIES Structure (Informal)

This is a hand-drawn diagram, drawn by by Martin Lyons, to understand the internal workings of EIES. The INF Function (Also known as INF, INFNI, INF(FNI)) is the basic focus of this diagram. The diagram may be a little inaccurate as there is no obvious method to transfer data back from INF to CONF (The Conferencing System), unless INPSE is dually used to do this. We're really not sure what INPSE's purpose was besides terminal routine handling, so it may act in both methods. Otherwise, everything is logical and is answered in other sections. SCHED (Scheduler) is elaborated on in Structure 4. MULWAT is the Interrupt handler. FILE is the EIES internal filesystem. SIGNON is the sign-on point for the user. Almost everything is intuitive and self-explanatory, except for the parts that really aren't, which are elaborated on in the diagrams below.

Structure #3: EIES Structure (Formal)

This more formal diagram is an excellent representation of the EIES system, though lacks some detail where as it elaborates on other points. More emphasis is put on the CLI (Command Line Interpreter) as the branch point for the INF function (This function is known by INF, INFNI, INF(FNI); though they're all basically the same input function). The CLI has five basic paths: It can operate on system-wide commands (such as compose, get, and display), CMDA (The main listing of Commands), USER (User functions such as MYPRIV), CMDB (The secondary listing of commands to be used as a last resort), and passing information back to the Input Function. At the INF level, input and output functions are passed through it, and relayed back to the Conferencing System.

Structure #4: Conferencing Diagram

This is a basic representation of the switching and routines that EIES utilized, but are not specific to the system. Disk routines are specified as an offshoot of the Conferencing system, which may seem odd at first seeing as one would think that Disk Routines would be tied directly into Input/Output processes, though in reality they are indirectly tied in. An input sequence is started at TTY I/O. It is passed to the scheduler, which is a very interesting bit of programming in itself. EIES was actually it's own operating system running ontop of FORTRAN. The technology at the time only allowed for a single-use system, so the scheduler "simulated" a multi-user system. The area marked "User Swap" represents a queue system based on priorities. When the user with the highest priority was serviced, that user was moved to the FORTRAN User Common by modifying their address to C00000, the next user was swapped in, and the queue was reset to position one. As Murray Turoff said in his interview, this method was efficient for the time and an interesting exhibit, though no one in their right mind would consider designing a modern system using FORTRAN the way they did back then. Afterwards, this data is passed back to the I/O routines, and transferred into the Conferencing system, where the disk routines can access the data and store it (The indirect connection that was mentioned earlier).

Structure #5: EIES CHOICE Structuring

The logic behind this structure is very simple to comprehend. A user is presented with an INITIAL CHOICE?, where they can decide the area they wish to go to: entering a 1 for messages, 2 for conferences, etcetera. When at the desired menu, the user can then enter the number of the function or feature they desire. This allows for the rather useful ability of answer ahead commands, saving time and energy. The user has entire control over the choices, as shown in the INTERACT examples.

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