MSDOS.SYS an important system file on MS-DOS

MS-DOS

MS-DOS is an operating system for x86-based personal computers. It was the most commonly used member of the DOS family of operating systems, and was the main operating system for IBM PC compatible personal computers during the 1980s to the mid 1990s, until it was gradually superseded by operating...

 and Windows 9x

Windows 9x

Windows 9x is a generic term referring to a series of Microsoft Windows computer operating systems produced since 1995, which were based on the original and later modified Windows 95 kernel...

 systems. It is run after IO.SYS

IO.SYS

IO.SYS is an essential part of MS-DOS and Windows 9x. It contains the default MS-DOS device drivers and the DOS initialization program.- Boot sequence :...

. 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

ASCII

The American Standard Code for Information Interchange is a character-encoding scheme based on the ordering of the English alphabet. ASCII codes represent text in computers, communications equipment, and other devices that use text...

 file containing configuration directives.

By default, the file is located in the root directory

Root directory

In computer file systems, the root directory is the first or top-most directory in a hierarchy. It can be likened to the root of a tree — the starting point where all branches originate.-Metaphor:...

 of the bootable drive/partition (normally C:\) and has the hidden, read-only, and system file attributes

Attrib

attrib is a command, in DOS, OS/2 and Microsoft Windows. The function of attrib is to set and remove file attributes...

 set.

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

IBMDOS.COM

IBMDOS.COM is the filename of the DOS kernel. It exists in DR-DOS and PC-DOS systems, with MS-DOS using MSDOS.SYS. The file is located in the root directory of the drive containing the operating system....

 for the same purpose.

Windows NT

Windows NT

Windows NT is a family of operating systems produced by Microsoft, the first version of which was released in July 1993. It was a powerful high-level-language-based, processor-independent, multiprocessing, multiuser operating system with features comparable to Unix. It was intended to complement...

-based operating systems (NT 3.1-4, 2000, XP, and 2003) use the NTLDR

NTLDR

NTLDR is the boot loader for all releases of Windows NT operating system up to and including Windows XP and Windows Server 2003. NTLDR is typically run from the primary hard disk drive, but it can also run from portable storage devices such as a CD-ROM, USB flash drive, or floppy disk...

 file and NT 6+ ( Vista, 2008, and 7) uses bootmgr

Windows Vista Startup Process

The startup process of Windows Vista, Windows Server 2008, Windows 7 and Windows Server 2008 R2 is different from any previous versions of Windows. For Windows Vista, the boot sector loads the Windows Boot Manager , which first looks for an active partition, then accesses the Boot Configuration...

instead, as they have a different boot sequence.

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