[Info-vax] Unix terminal drivers, was: Re: Moving away from OpenVMS

[John Wallace]

On May 18, 1:47 pm, Simon Clubley <clubley at remove_me.eisner.decus.org-
Earth.UFP> wrote:
> On 2012-05-17, JF Mezei <jfmezei.spam... at vaxination.ca> wrote:
>
>
>
> > Just consider the terminal driver's built-in timeout capability. If you
> > use that and move to Unix or even TCPIP, you need to re-invent the wheel.
>
> Unix terminal drivers have a built in timeout capability (at least the
> ones I am familiar with); the timeout is in units of 0.1 seconds.
>
> BTW, if you want to start sending terminal data over a TCP/IP connection
> on Unix use select() with a timeout.
>
> Simon.
>
> --
> Simon Clubley, clubley at remove_me.eisner.decus.org-Earth.UFP
> Microsoft: Bringing you 1980s technology to a 21st century world

I've done the Linux/Unix serial driver stuff. As you say, it's
sufficient for many applications. For user interfaces with timeouts
there's [n]curses too (think SMG, in concept anyway).

For one obscure project where process-level latencies meant the
standard serial timeout stuff was too coarse and the buffering was
inadequate, I took an existing Linux low level serial driver and put
what I needed into the driver itself. You could do that kind of thing
with VMS at one stage, but then DEC stopped documenting the serial
interface hardware (round about the CXY08 era?). Now a decade or two
later, with PCI serial interfaces with documentation, you could in
principle do a DIY driver under VMS again. Fortunately not many people
need to, and even fewer want to.