[Info-vax] DECnet Phase IV broken after VSI update

[Arne Vajhøj]

On 11/1/2021 6:45 PM, Lawrence D’Oliveiro wrote:
> On Tuesday, November 2, 2021 at 7:43:51 AM UTC+13, Simon Clubley
> wrote:
>> However, if you look at the man page you quote, you will see that
>> the actual pty devices are also created by a kernel mode device
>> driver on Linux ...
> 
> Of which there is only one, which is available to userland processes,
> and which is suitable for all cases where virtual terminals are
> needed. Implementing an SSH server? Use that. Implementing a GUI
> terminal emulator? Use that. Implementing a remote terminal server
> for some other network/comms protocol? Use that. Implementing a
> screen scraper to get info out of some legacy proprietary app? Use
> that.
> 
> Is FTDRIVER the same? If yes, then I take everything back, except to
> wonder why it doesn’t work better. :)

FTDRIVER is the pseudo terminal driver. It is not SSH specific for any
particular application.

To quote the docs:

<quote>
Chapter 6. Pseudoterminal Driver
This chapter describes the use of the pseudoterminal driver (FTDRIVER)
and the pseudoterminal
software.
A pseudoterminal is a software device that appears as a real terminal to
an application communicating
with it, but does not require the existence of a physical terminal. A
pseudoterminal consists of two
components: the pseudoterminal device and a control program. The control
program acts like a keyboard;
that is, anything written to the control program appears on the
pseudoterminal device as if the
keystrokes had been typed in at a physical terminal. The control program
also acts like a viewport to
the pseudoterminal device; that is, the control program reads anything
that is written by the system to
the pseudoterminal device.
A pseudoterminal allows an application to be set up on the control side
of the link to communicate
with another application that is on the pseudoterminal side. This
arrangement allows development of
applications that either simulate users or monitor the communication
between a real user (at a physical
terminal) and an application. As with other devices, the work of the
pseudoterminal is performed by a
device driver and is tightly coupled to the operating system.
</quote>

It may still be a bit different in nature from its Linux counterpart due
to the fact that VMS is different from Linux.

Arne