DOS device driver

File Format
Name	DOS device driver
Ontology	Electronic File Formats Executables DOS device driver
Extension(s)	.dos, .sys, .dev, .bin

DOS device drivers (often simply known as SYS files) are stored in a simple binary format. The filename extension DEV is used by the FreeDOS printer driver tool SPOOL. For the block device driver of the compression software Stacker, which was also included in some versions of the DR-DOS operating system or the Novell DOS and Caldera OpenDOS offshoots, the filename extension BIN is used.

Drivers are loaded into a contiguous block of memory; the segment part of data structure pointers is then adjusted to match the loading segment.

Some device drivers are stored in the MZ format instead of the "raw" SYS format.

Identification

Most DOS device drivers begin with the magic ID FF FF FF FF.

See also

• FreeDOS

Sample files

• http://www.ibiblio.org/pub/micro/pc-stuff/freedos/files/repositories/latest/util/spool.zip → SPOOL.DEV
• https://www.uwe-sieber.de/files/cfg_echo.zip → echo.sys
• https://ftp.zx.net.nz/pub/archive/novell/caldera_drdos/DR-DOS.703/images/disk02.144 → STACLOAD.BIN

Links

• SYS file structure in Ralf Brown's