PostScript is a page description language (PDL English, page description language), used in many printers and conventional manner, such as transport format graphics files in professional print shops. It is based on the work done by John Gaffney at "Evans & Sutherland" in 1976. The PostScript concept differed fundamentally by using a full programming language to describe a print image. Image that would later be printed on a laser printer or other output device quality, rather than a series of escape sequences of low level (this seems to Emacs, which exploded internal concept similar with respect to editing).
PCX, standing for Personal Computer Exchange, is an image file format developed by the now-defunct ZSoft Corporation of Marietta, Georgia. It was the native file format for PC Paintbrush and became one of the first widely accepted DOS imaging standards, although it has since been succeeded by more sophisticated image formats, such as BMP, JPEG, and PNG. PCX files commonly stored palette-indexed images ranging from 2 or 4 colors to 16 and 256 colors, although the format has been extended to record true-color (24-bit) images as well. PCX was designed during the early development of PC display hardware and most of the formats it supported are no longer used, Table A shows a list of the most commonly used PCX formats. Contemporary image editing programs may not read PCX files that match older hardware.