From Newsgroup: comp.misc

On Mon, 5 May 2025 08:30:03 -0400 (EDT), Scott Dorsey wrote:

In article <vv9fdc$3mhk4$1@dont-email.me>,
Lawrence D'Oliveiro <ldo@nz.invalid> wrote:

Meanwhile, Linux recently mainlined the PREEMPT_RT patches, where the
definition of real time is being able to provide sub-millisecond
response to playing or recording sound samples for pro audio.

That's still not hard realtime at all ...

Tell that to the audio engineers in particular. They are kind of sensitive
to the slightest bit of jitter in the timing of things.

But what they mean by "RT" isn't what hard realtime people mean by "RT"
which has nothing to do with what the transaction processing guys meant
as "RT." Do not get hung up on words, especially when people use the
same words for rather different concepts.

Particularly when the transaction processing folks are at the bottom of
that particular league table ...
--- Synchronet 3.20c-Linux NewsLink 1.2

From Newsgroup: comp.misc

On Mon, 05 May 2025 11:31:55 -0400, Dan Espen wrote:

Lawrence D'Oliveiro <ldo@nz.invalid> writes:

On Sun, 4 May 2025 20:53:42 -0400 (EDT), Scott Dorsey wrote:

You should check out Martin's "Design of Real-Time Computer Systems"
which was written in the early days of SAABRE and other transaction
processing systems.

Their idea of “real time” was responding in a few seconds, before the
user got frustrated enough to hit SEND again.

My experience: 360/30, 64K, 1968, locally attached 2260s, BTAM
application, instantaneous response.

“Instantaneous” to every keystroke? In something like a full-screen editor?
--- Synchronet 3.20c-Linux NewsLink 1.2

From Newsgroup: comp.misc

Dan Espen <dan1espen@gmail.com> wrote:

My experience: 360/30, 64K, 1968, locally attached 2260s, BTAM
application, instantaneous response.

And that was the bottom of the barrel too. It got so much better with
the newer channel controllers. And THEN we got SNA!
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
--- Synchronet 3.20c-Linux NewsLink 1.2

From Newsgroup: comp.misc

Lawrence D'Oliveiro <ldo@nz.invalid> writes:

On Mon, 05 May 2025 11:31:55 -0400, Dan Espen wrote:

Lawrence D'Oliveiro <ldo@nz.invalid> writes:

On Sun, 4 May 2025 20:53:42 -0400 (EDT), Scott Dorsey wrote:

You should check out Martin's "Design of Real-Time Computer Systems"
which was written in the early days of SAABRE and other transaction
processing systems.

Their idea of “real time” was responding in a few seconds, before the >>> user got frustrated enough to hit SEND again.

My experience: 360/30, 64K, 1968, locally attached 2260s, BTAM
application, instantaneous response.

“Instantaneous” to every keystroke? In something like a full-screen editor?

Huh?

What about block mode terminals don't you understand?
Of course it's instantaneous to every keystroke. And in this case
it was also instantaneous to the enter key. First online
app I developed. Online order entry.
--
Dan Espen
--- Synchronet 3.20c-Linux NewsLink 1.2

From Newsgroup: comp.misc

Dan Espen <dan1espen@gmail.com> wrote:

Lawrence D'Oliveiro <ldo@nz.invalid> writes:

On Mon, 05 May 2025 11:31:55 -0400, Dan Espen wrote:

Lawrence D'Oliveiro <ldo@nz.invalid> writes:

On Sun, 4 May 2025 20:53:42 -0400 (EDT), Scott Dorsey wrote:

You should check out Martin's "Design of Real-Time Computer Systems" >>>>> which was written in the early days of SAABRE and other transaction
processing systems.

Their idea of “real time” was responding in a few seconds, before the >>>> user got frustrated enough to hit SEND again.

My experience: 360/30, 64K, 1968, locally attached 2260s, BTAM
application, instantaneous response.

“Instantaneous” to every keystroke? In something like a full-screen
editor?

Huh?

What about block mode terminals don't you understand?
Of course it's instantaneous to every keystroke. And in this case
it was also instantaneous to the enter key. First online
app I developed. Online order entry.

Lawrence is more often trolling than not.
--- Synchronet 3.20c-Linux NewsLink 1.2

From Newsgroup: comp.misc

On Tue, 06 May 2025 08:19:05 -0400, Dan Espen wrote:

What about block mode terminals don't you understand?
Of course it's instantaneous to every keystroke.

But that’s only locally. Nothing goes to the mainframe unless you press
the SEND key.

That’s what “block mode” means.

Now imagine trying to run something more properly interactive, like Emacs
(or vi/vim, if you prefer), through such an interface.
--- Synchronet 3.20c-Linux NewsLink 1.2

From Newsgroup: comp.misc

Lawrence D'Oliveiro <ldo@nz.invalid> wrote:

Now imagine trying to run something more properly interactive, like Emacs >(or vi/vim, if you prefer), through such an interface.

You mean like word processing on PROFS where the editor is basically running
on the channel controller? That is great and extremely zippy over a slow network. Far better performance with any network latency than trying to
send everything over the connection.

CDC did something like this in a less elegant way with the Full Screen
Editor FSE. The PPU did most of the work but the PPU was tightly coupled
to the CPU so even though it offloaded the CPU completely it didn't help
any for slow connections.

But really, this has nothing to do with transaction processing systems,
which is the topic of this thread. Transaction systems need to have enough smarts at the terminal end to generate a transaction and the server needs
to have enough to execute it.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
--- Synchronet 3.20c-Linux NewsLink 1.2

From Newsgroup: comp.misc

On Tue, 6 May 2025 18:59:32 -0400 (EDT), Scott Dorsey wrote:

You mean like word processing on PROFS where the editor is basically
running on the channel controller? That is great and extremely zippy
over a slow network. Far better performance with any network latency
than trying to send everything over the connection.

I’m sure it is, but given the channel controller is not a general-purpose CPU, you are going to pay the price in app functionality.
--- Synchronet 3.20c-Linux NewsLink 1.2

From Newsgroup: comp.misc

Lawrence D'Oliveiro <ldo@nz.invalid> writes:

On Tue, 06 May 2025 08:19:05 -0400, Dan Espen wrote:

What about block mode terminals don't you understand?
Of course it's instantaneous to every keystroke.

But that’s only locally. Nothing goes to the mainframe unless you press the SEND key.

So 90%+ of the time, it's instantaneous.

Where I worked, it was also instant on Enter, Function keys, etc. All
the keys that required mainframe attention.
--
Dan Espen
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: comp.misc

On Thu, 08 May 2025 20:24:29 -0400, Dan Espen wrote:

Where I worked, it was also instant on Enter, Function keys, etc. All
the keys that required mainframe attention.

The idea that every single keystroke/mouse click might require CPU
attention (as is typical with interactive applications) is not something
that mainframes are optimized for.
--- Synchronet 3.21a-Linux NewsLink 1.2