![[*]](crossref.png)
).
Access to file systems is provided by the facilities described in this
chapter.
An executing T system interacts with the world outside by communicating with various external entities, including:
| people, via keyboards and displays; |
| file systems, via operating system calls, possibly over a communications network; |
| and processes, running on the same machine or on different machines. |
The language provides simple standardized interfaces to the first two of these. Particular implementations may provide more complete interfaces.
Standard access to a terminal is provided by the ports TERMINAL-INPUT
and TERMINAL-OUTPUT (page ).
Access to file systems is provided by the facilities described in this
chapter.