UNIX Power Tools

UNIX Power ToolsSearch this book
Previous: 41.7 Reading Verrrry Long Lines from the Terminal Chapter 41
Terminal and Serial Line Settings
Next: 41.9 Commands to Adjust Your Terminal
 

41.8 ptys and Window Systems

When window systems came along, UNIX needed a workaround, so that all the software that was written for ASCII terminals could continue to run in windows.

From the window system side, what it took was a terminal emulator - a program that makes a window act like a terminal. Most emulators imitate a DEC VT100 or VT102 terminal; they respond to its escape sequences, and in general masquerade pretty well.

But there's another side to the equation. The system needs to know what "terminal" a program is running on, so it can read input and send output to the right place. There's normally an association between a tty file and a physical device attached to a serial line. But what's the association for an abstraction on a workstation screen, on a device that's nothing like a serial line?

The answer was to come up with a "terminal-like" construct on the system side. It's called a pty, for pseudo-terminal, instead of a tty.

- TOR


Previous: 41.7 Reading Verrrry Long Lines from the Terminal UNIX Power ToolsNext: 41.9 Commands to Adjust Your Terminal
41.7 Reading Verrrry Long Lines from the Terminal Book Index41.9 Commands to Adjust Your Terminal

The UNIX CD Bookshelf NavigationThe UNIX CD BookshelfUNIX Power ToolsUNIX in a NutshellLearning the vi Editorsed & awkLearning the Korn ShellLearning the UNIX Operating System