Plug compatible: Difference between revisions

A '''plug-compatible''' machine is one that has been designed to be [[backward compatible]] with a prior machine. In particular, a new [[computer system]] that is plug-compatible has not only the same connectors and protocol interfaces to peripherals, but also [[binary code compatibility]]—it runs the same software as the old system. A '''plug compatible manufacturer''' or '''PCM''' is a company that makes such products.
One recurring theme in plug-compatible systems is the ability to be [[bug compatible]]<ref>"bug-for-bug compatible. Same as bug-compatible, with the additional implication that much tedious effort went into ensuring that each (known) bug was replicated.{{cite web
One|title=bug-for-bug recurring theme in plug-compatible systems is the ability to be [[|url= -for-bug-compatible]].html}}</ref> as well. That is, if the forerunner system had software or interface problems, then the successor must have (or simulate) the same problems. Otherwise, the new system may generate unpredictable results, defeating the full compatibility objective. Thus, it is important for customers to understand the difference between a "bug" and a "feature", where the latter is defined as an intentional modification to the previous system (e.g. higher speed, lighter weight, smaller package, better operator controls, etc.).
===PCM and IBM mainframes===
Most of these system vendors evenutally left the PCM market.<ref>"Hitachi has been in the mainframe business for 50 years and currently its AP series of systems are sold to major organisations across Japan. Hitachi Data Systems used to sell Hitachi-made IBM plug-compatible mainframes outside Japan but stopped doing so in 2000." {{cite newspaper |newspaper=The Register |date=May 24, 2017
|title=Hitachi exits mainframe hardware business |url=}}</ref>
==Non-computer usage of the term==