There are several possibilities, but Windows CE is fairly widely used.
single user/multi-tasking
PDA
Windows CE is a graphical operating system commonly used in embedded and portable devices, such as cellphones and PDAs.
Firmware, Operating System, and Utilities.
DOS is not necessary for computers. Lots of computers do not use DOS. What is necessary is an operating system. It is software that enables your computer to work and enables other software to run on a computer. There are many kinds of operating systems used on different types of computers. DOS (Disk Operating System) is just one operating system that was very common on PCs. Modern PCs do not use DOS now. Other types of computers use other operating systems and never used DOS.DOS is not necessary for computers. Lots of computers do not use DOS. What is necessary is an operating system. It is software that enables your computer to work and enables other software to run on a computer. There are many kinds of operating systems used on different types of computers. DOS (Disk Operating System) is just one operating system that was very common on PCs. Modern PCs do not use DOS now. Other types of computers use other operating systems and never used DOS.DOS is not necessary for computers. Lots of computers do not use DOS. What is necessary is an operating system. It is software that enables your computer to work and enables other software to run on a computer. There are many kinds of operating systems used on different types of computers. DOS (Disk Operating System) is just one operating system that was very common on PCs. Modern PCs do not use DOS now. Other types of computers use other operating systems and never used DOS.DOS is not necessary for computers. Lots of computers do not use DOS. What is necessary is an operating system. It is software that enables your computer to work and enables other software to run on a computer. There are many kinds of operating systems used on different types of computers. DOS (Disk Operating System) is just one operating system that was very common on PCs. Modern PCs do not use DOS now. Other types of computers use other operating systems and never used DOS.DOS is not necessary for computers. Lots of computers do not use DOS. What is necessary is an operating system. It is software that enables your computer to work and enables other software to run on a computer. There are many kinds of operating systems used on different types of computers. DOS (Disk Operating System) is just one operating system that was very common on PCs. Modern PCs do not use DOS now. Other types of computers use other operating systems and never used DOS.DOS is not necessary for computers. Lots of computers do not use DOS. What is necessary is an operating system. It is software that enables your computer to work and enables other software to run on a computer. There are many kinds of operating systems used on different types of computers. DOS (Disk Operating System) is just one operating system that was very common on PCs. Modern PCs do not use DOS now. Other types of computers use other operating systems and never used DOS.DOS is not necessary for computers. Lots of computers do not use DOS. What is necessary is an operating system. It is software that enables your computer to work and enables other software to run on a computer. There are many kinds of operating systems used on different types of computers. DOS (Disk Operating System) is just one operating system that was very common on PCs. Modern PCs do not use DOS now. Other types of computers use other operating systems and never used DOS.DOS is not necessary for computers. Lots of computers do not use DOS. What is necessary is an operating system. It is software that enables your computer to work and enables other software to run on a computer. There are many kinds of operating systems used on different types of computers. DOS (Disk Operating System) is just one operating system that was very common on PCs. Modern PCs do not use DOS now. Other types of computers use other operating systems and never used DOS.DOS is not necessary for computers. Lots of computers do not use DOS. What is necessary is an operating system. It is software that enables your computer to work and enables other software to run on a computer. There are many kinds of operating systems used on different types of computers. DOS (Disk Operating System) is just one operating system that was very common on PCs. Modern PCs do not use DOS now. Other types of computers use other operating systems and never used DOS.DOS is not necessary for computers. Lots of computers do not use DOS. What is necessary is an operating system. It is software that enables your computer to work and enables other software to run on a computer. There are many kinds of operating systems used on different types of computers. DOS (Disk Operating System) is just one operating system that was very common on PCs. Modern PCs do not use DOS now. Other types of computers use other operating systems and never used DOS.DOS is not necessary for computers. Lots of computers do not use DOS. What is necessary is an operating system. It is software that enables your computer to work and enables other software to run on a computer. There are many kinds of operating systems used on different types of computers. DOS (Disk Operating System) is just one operating system that was very common on PCs. Modern PCs do not use DOS now. Other types of computers use other operating systems and never used DOS.
The MVS operating system was the most commonly used operating system used on mainframe computers. The MVS operating system was developed by IBM and was first released in 1974.
the operating system which is basically used for gaming and designing of the gaming is called an rock operating system
The QNX operating system is mostly used for industrial purpose. It is a real time Operating system as opposed to Linux that is considered a basic operating system.
UNIX
dos operating system
Unix
Nothing
disk operating system
There are several of them such as Guest, User, Backup Operator, Power User, Administrator. Also there are some users which can be used only by the operating system: System, and others.