| 释义 |
- Boot sequence
- Disk layout requirements
- See also
- References
- External links
{{distinguish|IOSYS}}{{refimprove|date=August 2014}}{{Mono|IO.SYS}} is an essential part of MS-DOS and Windows 9x. It contains the default MS-DOS device drivers (hardware interfacing routines) and the DOS initialization program. Boot sequence In the PC bootup sequence, the first sector of the boot disk is loaded into memory and executed. If this is the DOS boot sector, it loads the first three sectors of {{Mono|IO.SYS}} into memory and transfers control to it. {{Mono|IO.SYS}} then: - Loads the rest of itself into memory.
- Initializes each default device driver in turn (console, disk, serial port, etc..). At this point, the default devices are available.
- Loads the DOS kernel and calls its initialization routine. The kernel is stored in {{Mono|MSDOS.SYS}} with MS-DOS and in {{Mono|IO.SYS}} with Windows 9x. At this point, "normal" file access is available.
- Processes the {{Mono|MSDOS.SYS}} file with Windows 9x.
- Processes the {{Mono|CONFIG.SYS}} file, in MS-DOS 2.0 and higher and Windows 9x.
- Loads {{Mono|COMMAND.COM}} (or other operating system shell if specified).
- Displays the bootsplash in Windows 9x. If {{Mono|LOGO.SYS}} is present, it is used as the bootsplash. Otherwise, the bootsplash in {{Mono|IO.SYS}} is used.
IBM PC DOS and DR DOS use the file IBMBIO.COM for the same purpose; it in turn loads IBMDOS.COM. Disk layout requirements - The two first entries of the root directory must be allocated by {{Mono|IO.SYS}} and {{Mono|MSDOS.SYS}}, in that order.
- {{Mono|IO.SYS}} must be the first file stored in the FAT directory table for files.
- The files {{Mono|IO.SYS}} + {{Mono|MSDOS.SYS}} must be contiguous.
However, v3.3 allows sector 4 and higher to be fragmented. v5.0 allows the first 3 sectors of {{Mono|IO.SYS}} to be allocated anywhere (as long as they are contiguous). See also- MSDOS.SYS
- COMMAND.COM
- IBMBIO.COM
- List of DOS system files
References External links- MS-DOS Device Driver Names Cannot be Used As File Names — includes list of default device drivers.
- SYS.COM Requirements in MS-DOS Versions 2.0-6.0 — includes requirements for IO.SYS to be loaded.
{{operating-system-stub}}{{Windows-stub}} 1 : DOS files |