MSDOS.SYS

MSDOS.SYS an important system file on MS-DOS and Windows 9x systems. It is run after IO.SYS. In MS-DOS, it contains the core operating system code, the kernel. On Windows 9x systems, the DOS kernel code is merged into IO.SYS, and MSDOS.SYS is an ASCII file containing configuration directives.

By default, the file is located in the root directory of the bootable drive/partition (normally C:\) and has the hidden, read-only, and system file attributes set.

IBM PC-DOS and DR DOS used the file IBMDOS.COM for the same purpose.

Windows NT-based operating systems (NT 3.1-4, 2000, XP, and 2003) use the NTLDR file and NT 6+ ( Vista, 2008, and 7) uses bootmgr instead, as they have a different boot sequence.

See Also

• IBMDOS.COM

External links

MSDOS.SYS in Windows 9x (95/98/ME):

• MicroSoft Knowledge Base (MSKB): List of MSDOS.SYS articles
• MSKB: Contents of the Windows Msdos.sys File
• MSKB: How to create an Msdos.sys file larger than 1024 bytes
• MDGx: Windows 95/98/ME Complete MSDOS.SYS Reference
• UKT Support: Contents of the MSDOS.SYS File
• Computer Hope: Information about Window MSDOS.SYS file