> On Jan 2, 2022, at 9:14 PM, Grant Taylor via cctalk <cctalk@classiccmp.org>
> wrote:
>
> On 1/2/22 6:59 PM, ben via cctalk wrote:
>> But can the Pi handle a gazillion students all time sharing at once @ 2400?
>
> I think that will depend on how you connect the serial terminals.
>
> I know that it's possible to establish network connectivity to serial
> terminal servers. I don't know how many of those terminal servers can be
> connected to SimH. It may be better to use LAT between terminal servers and
> VMS running in the emulated VAX.
>
That was the whole point of LAT. At the time almost all serial terminals were
connected by DZ-style interfaces, so 1 interrupt when you typed a character and
a second interrupt after the character was echoed. LAT created a virtual
circuit between the terminal server and a specific host. The slot layer ran
over the virtual circuit between a logical terminal on the host and a physical
terminal on the server. Data messages at the virtual circuit layer were limited
to no more frequent than a terminal server parameter ( default 80mS). With
appropriate optimizations and data availability it was possible to shrink the
interrupt load on the host to 1-2 interrupts/ethernet packet (say around 1400
characters). There were a lot of internal religious wars around the use of
CTERM/Telnet/LAT.
After finishing DECnet-Ultrix I had a couple of weeks of spare time and
implemented a prototype Ultrix-LAT - one of the good things that came out of
having a MicroVAX I in my office!
John.
>> How long was the VAX timesharing era as I suspect networked PC's come out
>> soon after that.
>
> Good question.
>
>
>
> --
> Grant. . . .
> unix || die
