Most modern UNIX systems run as a 64-bit Operating System.
Yes, it does.
Names Pipes and unnamed pipes
It supports multi-user multi-tasking.
Most of MS-DOS' commands were based on those of Unix and CP/M. 'cd', 'dir', 'clear', and 'echo' are usually found in both. MS-DOS added it's own commands, however, and made some different from those of existing versions of Unix, and no one saw any reason to change the names of existing ones in Unix.
There are 8192 bits in a kilobyte.
Windows 7 (64-bit), Ubuntu, and I Think Macs
'cu' stands for Call Unix. It used to be used for calling dialup services from one Unix to another. Hardly used anymore with networks (which are much faster)
see: What_is_the_cost_of_a_Unix_server
Photoshop supports images up to 32 bit/channel.
Jose Luis
Microsoft Windows XP 64 Bit Edition ?
Unix comes in multiple distributions some more secure than others. Much of the security also comes from how the system is configured. Most unix systems are fairly secure.