what is "tty" on FreeBSD?

Question

"uprintf() function outputs to the current process' controlling tty"

This is description of uprintf() from Freebsd MAN. I don't understand what is tty? Thanks.Nice holiday!

Answer 1

A tty is an abstract model of a character I/O device. It is most directly a system interface, with corresponding application program interfaces.

Once upon a time there was a corporation named Teletype. They made hardcopy automatic typewriter devices that were used as communications terminals for decades and then repurposed as hardcopy computer terminals. Teletype was generalized to teletypewriter or teleprinter in order to avoid using a brand name.

Originally they were functional but rather ugly...

But later models (this model 43 is from the late 1970's) were quite beautiful...

The microprocessor made video display terminals practical, previously, the hard copy terminals were quite a bit cheaper and vastly more popular. As it happens, the Unix tty abstraction worked great for video terminals as well.

And, it worked just fine for xterm windows, and xterm's children (usually called Terminal) that will be found on Linux, Mac, and other descendants of Unix...