What is dos based operating system?

A computer based operating system  OS is the most important software that runs on a computer. It manages the computer's memory, processes, and all of its software and hardware. It also allows you to communicate with the computer without knowing how to speak the computer's language .Without an operating system, a computer is useless.

Basically, your computer's operating system (OS) manages all of the software and hardware on the computer. Most of the time, there are many different computer programs running at the same time, and they all need to access your computer's central processing unit (CPU), memory, and storage. The operating system coordinates all of this to make sure each program gets what it needs.

There are many types of operating systems  as OS usually come preloaded on any computer you buy. Most people use the operating system that comes with their computer, but it's possible to upgrade or even change operating systems. The three most common operating systems for personal computers are Microsoft Windows, Apple Mac OS X, andLinux. 

However, Modern operating systems use a graphical user interface, or GUI (pronounced gooey). A GUI lets you use your mouse to click icons, buttons, and menus, and everything is clearly displayed on the screen using a combination of graphics and text. Each operating system's GUI has a different look and feel, so if you switch to a different operating system it may seem unfamiliar at first. However, modern operating systems are designed to be easy to use, and most of the basic principles are the same.

(DOS) The original disk operating system from IBM.

DOS was the low-end OS of choice on the IBM 360, the high-end system was called just ”OS ". DOS had a smaller kernel and less functionality than OS and could run on the typical 32K 360/30 and 64K 360/40 class machines. DOS was a successor to TOS.

Operating system

(DOS) The name of a number of operating systems which include facilities for storing files on disk, often used to refer to Microsoft DOS. Such a system must handle physical disk I/O, the mapping of file names to disk addresses and protection of files from unauthorized access (in a multi-user system). A DOS should present a uniform interface to different storage device such as floppy disks, hard disks and magnetic tape drives. It may also provide some kind of locking to prevent unintentional simultaneous access by two processes to the same file (or record).

DOS (Disk Operating System) was the Command Line Based system IBM and Microsoft used initially for running different applications.

(1) Acronym for disk operating system. The term DOS can refer to any operating system, but it is most often used as a shorthand for MS-DOS (Microsoft disk operating system). Originally developed by Microsoft for IBM, MS-DOS was the standard operating system for IBM-compatible personal computers.

The initial versions of DOS were very simple and resembled another operating system called CP/M. Subsequent versions have became increasingly sophisticated as they incorporated features of minicomputer operating systems. However, DOS is still a 16-bit operating system and does not support multiple users or multitasking.

For some time, it has been widely acknowledged that DOS is insufficient for modern computer applications. Microsoft Windows helped alleviate some problems, but still, it sat on top of DOS and relied on DOS for many services. Even Windows 95 sat on top of DOS. Newer operating systems, such as Windows NT and OS/2 Warp, do not rely on DOS to the same extent, although they can execute DOS-based programs. It is expected that as these operating systems gain market share, DOS will eventually disappear. In the meantime, Caldera, Inc. markets a version of DOS called DR-OpenDOSthat extends MS-DOS in significant ways.

full agree with ms. ghada on her answer

Well answer add by Ghada Eweda

I'm thinking that it refers to DOS = Direct Operating System, where you have an intense use of keyboard, if well remember MD it means Make Directory, CD Enter the Directory (not file or folder) etc, any way a basic software to initiate and use the PC. 

Basm allah alrahman alrahim

all windows operating system before NT was DOS based , that mean MS-DOS-based Microsoft Windows (95, 98, and Millennium Edition)

that mean structured at DOS

DOS (Disk Operating System) was the first widely-installed operating system for personal computers. (Earlier, the same name had been used for an IBM operating system for a line of business computers.)

OS USING MANY FIELD SOFWARE RUNNING SUPPORT FILE 

RAM PROSSES BASED ON OS

Experts already answered well this question, thank you Mr Vaqar Ali Sayyed for the invitation.