This is a very subjective question, with no good answer - it all depends on what the user wants to do and what their skill set is. There is no one "best" operating system for everyone, regardless of their skill set.
For computers the term OS refers to Operating System.
DOS, which stands for Disk Operating System.
All modern day computers have some form of operating system.
Yes, that is was the operating system of Macintosh Computers are called.
window operating system
disk operating system
All computers must have some kind of Operating system to function.
Windows is an operating system developed by Microsoft. Apple makes Macintosh computers that run Apple's own Mac OS X operating system but can also run the Windows operating system.
Industrial computers will be great for workstation use, assuming the operating system supports your application. For instance, Itanium computers or HP-UX servers may not make good workstations due to application incompatibility.
NOS (Network Operating System)
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.
All computers need some sort of operating system.