cdl@mplvax.UUCP (12/17/83)
Roughly speaking, a major device is the software's name for what a hardware person would call a controller, while a minor device is the software name for one of the (perhaps many) peripheral devices which are run by that controller. Thus, major devices include things like 'hp', 'up', 'rk', 'rp' disk controllers,each of which might control several disk drives; 'hs', 'tm', 'ts' tape controllers with associated tape drives; 'dz', 'dh' terminal controllers with associated communication lines. Some major devices tend to be singular in their attached minor device, e.g. 'lp', 'va', 'vp' printers. Strictly speaking, a major device refers to all the stuff that can be run by a single piece of software (the device driver), but the mapping to real hardware is the way to think about it. Carl Lowenstein {ucbvax,philabs}!sdcsvax!mplvax!cdl Marine Physical Lab., U. C. San Diego