Redhat and Mandrake are not versions of any operating system. Both are itself standalone Linux operating systems.
Redhat is a Linux based operating system.
Linux RedHat
Windows Server 2008, Redhat Linux, Solaris
Like Windows 7 Redhat is also an operating system. It is not easy to install an operating system into another. But the recent advances in software world gives an opportunity through virtualization, we can create a virtual machine and then install Windows7 into it. Virtualbox software may assist.
Android is an operating system for mobile phones. Five android versions are Lollipop, marshmallow, gingerbread, alpha and beta.
"Distros", or distributions.
No, you can create multiple accounts on most of the OS's
DOS
NetworkManager refers to wireless for the operating system known as Ubuntu. Any site such as RedHat or the Ubuntu website can provide one with information about networkmanager.
yes
If you are referring to the operating system then a Mac's default operating system is called Mac OS X. A Mac can be downgraded to run most versions of the Windows operating system from XP to 7.
MS-DOS, PC-DOS, FREEDOS.