Technology / Computers / Config.SYS: The configuration file for DOS systems. Each time a DOS computer boots up, it reads from the CONFIG.SYS file (if present) and will execute any prewritten commands. A couple of the most common file held within the Config.sys are: BUFFERS= and FILES=. These commands enable the system to specify the buffer size and the number of files that are allowed to open at once. Commands can also be held in the Config.sys that will install device drivers.