Security is a difficult and sometimes controversial thing to analyze. The only truly "secure" operating systems are those that have no contact with the outside world. The firmware in your DVD player is a good example.
Among all modern general purpose operating systems (Windows, Mac OS X, Linux, Solaris, FreeBSD, NetBSD, OpenBSD) the most secure by defualt is by far OpenBSD. OpenBSD has an extremely stringent security auditing policy; only two remote attack vulnerabilities have been found in the last ten years. This is because OpenBSD doesn't create a large attack surface by running a large number of networked apps.
Of course, the sad fact is that any networked operating system can be made insecure through careful misconfiguration. Window's problems with security stem mainly from the fact that it runs with a large number of network services on by default, and that it (XP and prior) let the user run with full privileges by default. Windows Vista attempted to fix this issue, but people rejected it as "too confusing" and complained that their old apps did not work correctly under limited accounts.
Mac OS X is better about user permissions, but still has had a (in)decent number of remote exploits. Apple's slow response to patch many of these issues will be even more worrying if it gains significant market share.
Most Linux distributions have an excellent policy of quickly patching known security vulnerabilities. Unfortunately, two of the top ten distros deliberately use outdated code (Damn Small Linux) or make it too easy to run as a privileged user by mistake (Damn Small Linux, Puppy Linux). Were these distros to gain significant popularity, their users would be exposed to a larger number of vulnerabilites than if they encouraged proper security policies.
Linux is the Most Secure Because it's Highly Configurable
Security and usability go hand-in-hand, and users will often make less secure decisions if they have to fight against the OS just to get their work done
Windows and Macos
Windows XP was the most popular operating system.
No, it is not possible to construct a secure operating system for those computer systems which do not provide a privileged mode of operation in hardware.
window operating system
disk operating system(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.
Windows 2000
Windows XP was the most popular operating system.
No, it is not possible to construct a secure operating system for those computer systems which do not provide a privileged mode of operation in hardware.
flexibe, faster to run programme ,very secure , portability
flexibe, faster to run programme ,very secure , portability
Linux is not an power full Operating system XP is the most powerfull operating system
the most popular operating system multitasking is kernel
The OS (operating system). Examples of OSs are windows XP and Linux.
disk operating system(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.
Unix is one of the more secure operating systems, but it would be difficult to give an exact answer. It is very easy (and possible) to make any operating system insecure. It takes individuals some amount of time to secure any operating system, and Unix is no exception to that.
Windows 8 is the most current windows client operating system.