When I try to use any application, the interface works very slow. The same application works in OpenOS just fine. Edit.lua and shell are extremely laggy as well.
Here's the video demonstraion:

And now in OpenOS:

Plan9k hasn't been updated for 6 years, and appears to be effectively abandoned.

I can't switch to OpenOS as Plan9k has separated kernel space and user space, it's unsafe to use programs like reactor control interface in OpenOS, where kernel space is not separated, so I really need Plan9k to work faster. I've tried to figure out what's wrong myself, but I don't see any issues with the code, and I am not actually a good lua coder, so I can't do anything with it.

What hardware did you put into the computer? (In Game)

This particular one has 2 1.5 level RAM sticks, 1 hdd, a 1st level cpu and a 3rd level video card.
Also tested on the server with 3rd level everything except for RAM. There are 4 sticks of the magical memory from... computronics I think. But I see no difference in performance. Can record video with this server

i recommend just maxing out every part, and maybe asking the server owner for the config file for oc and computronics so you can see the stats of parts

Everything is already maxed out, but this doesn't really help. Since I am server owner, I have access to the config file, but I can say that it's unchanged.

ok. can u send me link to the program making the lag aswell as the mod list (and if possible i would like to join your server)

also, can you tell me what Plan9K distro u are using

also, are you running off an hdd or a floppy

Forgot about the screenshot XD

I am running from an hdd, using Plan9k full distro installed from a flopy. The attached screenshot shows the list of mods I use. And sadly, no opportunity to join my server as I had to relocate it to the home PC, where I have an additional NAT set up by my ISP after my router.

And here is the reactor code:
https://pastebin.com/nAHaGmm6

Try using one of the recent dev builds from the Actions tab (make sure it's for 1.12.2)

Only found one made 2 months ago
It's OpenComputers-MC1.12.2-0.0.0+b823414
Will try it now

Update:

Hm. The version replacement stuff seems to be broken. Well then. @asiekierka is the 0.0.0 intended?

I wouldn't say it is, no...

@fixinit75 plan9k has some extremely clever pipe code that manages all io in the system. but it is also extremely inefficient for a lua runtime to handle. There won't be any fixes/improvements to plan9k

If you need safeguards on your scripts, use pcall/xpcall -- if you're using scripts that break the system env, you can sandbox your env.