What are the differences between MS-DOS and Windows?

Linux

Unix usually refers to a family of operating systems that are similar in function or descendants of the original Unix operating system developed at AT&T Bell Laboratories. This includes a large portion of modern operating systems, including:

• All Linux distributions (Red Hat, SuSE, Fedora, Debian, etc.)
• BSDs (FreeBSD, NetBSD, OpenBSD, DragonflyBSD, Mac OS X)
• Solaris
• HP-UX
• AIX

Unix-like systems are multi-user and multiprocessing operating systems; that is, more than one user can be using the machine at one time, and each user can run multiple processes, or programs. The most common way to interact with a Unix-like system is a text command shell, but many users choose to use graphical desktop environments as well.

On the contrary, DOS refers to a family of single-user operating systems first developed for IBM-compatible PCs. Generally, DOS is also single-tasking, meaning that the operating system can only run one program at a time. DOS is not a very modern operating system; a program bug can easily crash the entire computer whereas on modern operating systems (Windows, Mac, Linux, Unix, etc.), program bugs are "caught" by the operating system.

Unix has traditionally been used primarily in server environments, but is also gaining ground as a desktop operating system. Most open source Unix-like operating systems have advanced considerably in terms of user-friendliness. Despite this, Unix's simplicity also means that users are expected to know more, and are generally still more difficult to use than Windows or Mac.

DOS has been mostly replaced by Windows and Mac as PCs. DOS installations still remain today to run older DOS applications, including games to military accounting software.