MSDOS.SYS
The kernel of a PC-compatible DOS is stored in the MSDOS.SYS file for MS-DOS or IBMDOS.COM for PC DOS and DR DOS and is located in the main directory of the file system.
MSDOS.SYS is initialized by IO.SYS under MS-DOS and loads the device drivers and settings specified in CONFIG.SYS . If CONFIG.SYS is missing or if nothing else is specified, MSDOS.SYS starts the command line interpreter COMMAND.COM in the main directory of the boot drive .
Under PC DOS, which is a further developed MS-DOS with the same code base , the file is called IBMDOS.COM and is initialized from IBMBIO.COM , but is otherwise identical.
Under DR DOS the file is called DRBDOS.SYS up to version 3.41 and also IBMDOS.COM from version 5.0 . It contains the BDOS kernel derived from CP / M and is only fully compatible with PC DOS and thus with MS-DOS with Novell DOS 7 . The kernel is called from the counterpart to IO.SYS , which has the file name DRBIOS.SYS (up to version 3.41) or IBMBIO.COM (from version 5.0).
Under Windows 9x , MSDOS.SYS was integrated into IO.SYS and MSDOS.SYS became a configuration file that allows start options for DOS-based Windows.
Individual evidence
- ↑ Microsoft KB Article 118579 : Contents of the Windows Msdos.sys File , accessed January 26, 2011