User interface

Membrane switches, rubber keypads and touchscreens are examples of the physical part of the Human Machine Interface which we can see and touch.

However, this latter usage is seeing increasing application in the real-life use of (medical) prostheses—the artificial extension that replaces a missing body part (e.g., cochlear implants).

A means of tracking parts of the body is required, and sensors noting the position of the head, direction of gaze and so on have been used experimentally.

The input side of the user interfaces for batch machines was mainly punched cards or equivalent media like paper tape.

With the limited exception of the system operator's console, human beings did not interact with batch machines in real time at all.

The program cards were not punched on the computer itself but on keypunches, specialized, typewriter-like machines that were notoriously bulky, unforgiving, and prone to mechanical failure.

The software interface was similarly unforgiving, with very strict syntaxes designed to be parsed by the smallest possible compilers and interpreters.

Eventually, operators would feed the deck to the computer, perhaps mounting magnetic tapes to supply another dataset or helper software.

But there were worse fates than the card queue; some computers required an even more tedious and error-prone process of toggling in programs in binary code using console switches.

Accordingly, command-line systems allowed the user to change their mind about later stages of the transaction in response to real-time or near-real-time feedback on earlier results.

But these interfaces still placed a relatively heavy mnemonic load on the user, requiring a serious investment of effort and learning time to master.

[11] The earliest command-line systems combined teleprinters with computers, adapting a mature technology that had proven effective for mediating the transfer of information over wires between human beings.

Teleprinters had originally been invented as devices for automatic telegraph transmission and reception; they had a history going back to 1902 and had already become well-established in newsrooms and elsewhere by 1920.

In reusing them, economy was certainly a consideration, but psychology and the rule of least surprise mattered as well; teleprinters provided a point of interface with the system that was familiar to many engineers and users.

These cut latency further, because characters could be thrown on the phosphor dots of a screen more quickly than a printer head or carriage can move.

They helped quell conservative resistance to interactive programming by cutting ink and paper consumables out of the cost picture, and were to the first TV generation of the late 1950s and 60s even more iconic and comfortable than teleprinters had been to the computer pioneers of the 1940s.

The pioneering applications of this kind were computer games and text editors; close descendants of some of the earliest specimens, such as rogue(6), and vi(1), are still a live part of Unix tradition.

This defined that a pulldown menu system should be at the top of the screen, status bar at the bottom, shortcut keys should stay the same for all common functionality (F2 to Open for example would work in all applications that followed the SAA standard).