HP OpenVMS Systems Documentation

Content starts here 6.3 Pseudoterminal Driver Device Information
HP OpenVMS I/O User’s Reference Manual: OpenVMS Version 8.4 > Chapter 6 Pseudoterminal Driver

6.3 Pseudoterminal Driver Device Information

The pseudoterminal inherits its device characteristics from the system default parameters, with the following exceptions:

  • The device inherits initial device characteristics from the SYSGEN-supplied default values. You can modify the device characteristics during device creation by supplying new characteristics.

  • The HOSTSYNC terminal characteristic is always set.

  • The device is set to NOMODEM and cannot be set to MODEM.

  • The device is set not to time output character transmission. Hardware controllers time output character transmission to determine whether the controller is broken.

You can obtain information on pseudoterminal characteristics by using the Get Device/Volume Information ($GETDVI) system service, as described in “Terminal Driver Device Information” and the HP OpenVMS System Services Reference Manual.

Applications should assign a channel other than the control channel to read data from, write data to, read, or alter the pseudoterminal characteristics. An attempt to perform such I/O with the control channel, or any other attempt to queue an illegal or unsafe I/O request, results in an SS$_CHANINTLK error.