- * A pseudo-teletype is a special device which is not unlike a pipe.
- * It is used to communicate between two processes. However, it allows
- * one to simulate a teletype, including mode setting, interrupt, and
- * multiple end of files (all not possible on a pipe). There are
- * really two drivers here. One is the device which looks like a TTY
- * and can be thought of as the slave device, and hence its routines
- * are prefixed with 'pts' (PTY Slave). The other driver can be
- * thought of as the controlling device, and its routines are prefixed
- * by 'ptc' (PTY Controller). To type on the simulated keyboard of the
- * PTY, one does a 'write' to the controlling device. To get the
- * simulated printout from the PTY, one does a 'read' on the controlling
- * device. Normally, the controlling device is called 'ptyx' and the
- * slave device is called 'ttyx' (to make programs like 'who' happy).