🚀 go-pugleaf

>From BILLW@SRI-KL Sun Apr  4 10:01:00 1982
I used SPF under TSO in an IBM 370 quite a bit, working summers for an
Oil company while going to school.  This is one of the display editors
available for an IBM (actually, you can think of it as a complete shell
that is much easier to use than TSO), and its actually quite good.  It
is dependent on having 3270 type terminals though, which brings up:

How a 3270 type terminal works:

 Well, It's a screen oriented terminal.  Cursor motion and editing
keys take effect locally, after a CPU has sent a screens worth of text
or so (you actually only have to send a full screen once, to define
the fields. After that, you need only send the fields that change, I
think).  When you hit an activation key (Enter, Clear, Attn, one of up
to 24 PF keys), the MODIFIED fields are transmitted back to the host,
along with signals telling you where the cursor was, and which key was
pressed and so on.

Thus it is somewhat dependent on having a nice fast line to the CPU,
but the system was quite usable even after we moved down the street
and had a 9600 baud leased line to the CPU serving 6 terminals or so.
You can do an awful lot of editing before you have to wake up the CPU.
Typically your PF keys are tied to commonly used functions: Scroll up/down/
left/right, repeat find, repeat change, exit, abort and so on.

As an amusing aside, I first used this SPF system before we got our EMACS
look-alike (FINE, under TOPS-10).  I was using TECO, and seriously considered
writing an SPF look-alike to use...

Not everthing running on an IBM is bad...
Bill Westfield