Editing User interface (section)

=== 1945–1968: Batch interface ===

[[File:LCM - IBM 029 Card Punch 01.jpg|thumb|alt=IBM 029 card punch|IBM 029]]

In the batch era, computing power was extremely scarce and expensive. User interfaces were rudimentary. Users had to accommodate computers rather than the other way around; user interfaces were considered overhead, and software was designed to keep the processor at maximum utilization with as little overhead as possible.

The input side of the user interfaces for batch machines was mainly [[punched card]]s or equivalent media like [[paper tape]]. The output side added [[line printer]]s to these media. With the limited exception of the system [[System console|operator's console]], human beings did not interact with batch machines in real time at all.

Submitting a job to a batch machine involved first preparing a deck of punched cards that described a program and its dataset. The program cards were not punched on the computer itself but on [[Keypunch|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.

[[File:Card puncher - NARA - 513295.jpg|left|thumb|Holes are punched in the card according to a prearranged code transferring the facts from the census questionnaire into [[statistics]].]]

Once the cards were punched, one would drop them in a job queue and wait. Eventually, operators would feed the deck to the computer, perhaps mounting [[Magnetic tape data storage|magnetic tapes]] to supply another dataset or helper software. The job would generate a printout, containing final results or an abort notice with an attached error log. Successful runs might also write a result on magnetic tape or generate some data cards to be used in a later computation.

The [[turnaround time]] for a single job often spanned entire days. If one was very lucky, it might be hours; there was no real-time response. 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. The very earliest machines had to be partly rewired to incorporate program logic into themselves, using devices known as [[plugboard]]s.

Early batch systems gave the currently running job the entire computer; program decks and tapes had to include what we would now think of as [[operating system]] code to talk to I/O devices and do whatever other housekeeping was needed. Midway through the batch period, after 1957, various groups began to experiment with so-called "[[Compile and go system|load-and-go]]" systems. These used a [[Resident monitor|monitor program]] which was always resident on the computer. Programs could call the monitor for services. Another function of the monitor was to do better error checking on submitted jobs, catching errors earlier and more intelligently and generating more useful feedback to the users. Thus, monitors represented the first step towards both operating systems and explicitly designed user interfaces.