PiDP-10 odd issue with CON (slows down when doing a large window)

[Steve Lewis]

So I've noticed something odd:  for the light yellow background CON TTY window, if I increase that window to have room to show more than about 50 rows, the whole RPi OS starts to dramatically slow down.

And if I keep it large like that, it seems to gradually get slower and slower, eventually can barely move the mouse.

But if I shrink that window back to a more normal 20-50 rows, the performance snaps back to normal and I can move the mouse cursor just fine.

I've done this about 10 times in a row now, it does seem correlated to the visible-row length of that CON terminal.

I've run ntop and nothing seems unusual there (quad cpus temps around 55degC, memory is about 950M / 8GB, CPU cores riding around 30-40% at most).

Its a bummer because I had hoped to snap the CON window to the right side, along the entire length of the screen and have a long history of TTY content printed.

And in case it matters, I am using a 27" display at 3840x2160.   I do have a 340 and cscope window up also, but nothing actively going to those.   I can make the CON window about 1/3rd down from the top, going much further than that starts the sluggish mouse movement behavior until I shrink the window back to under 1/3rd height.

-Steve

[Steven A. Falco]

That is a pretty high resolution display. Which model of Pi are you using? I don't have personal experience with a 4K monitor, but you probably want one of the newer ones like a Pi5.

Steve

[oscarv]

Steve,

I'm not surprised, the little Teletype CON TTY program is very poorly written (by me). It needs replacing - it just worked well enough that I included it. Hoping that no-one would look at the source code, ever.

Something interesting just came out:

https://github.com/progs-n-things/asr33emu

It's aimed at the PiDP-8, but I think it would work fine. So at some point, it will be the replacement.

Kind regards,

Oscar.