CopyMem Quick & Small released!

[psxphill]

That is just multitasking unfriendly editor. It is different requirement.

No it is exactly the same requirement as the text editor being able to use as much of your cpu as it wants as long as it can keep up with your typing. If you have other secret requirements that are obvious to you then you should specify them.
 
There may be software running in the background that needs to run at a high priority so that only 50% of cpu is left. The text editor needing 100% of cpu to keep up with typing is now unable to keep up with your typing.

I'm using quite extreme examples because it makes the maths easier, I understand that you can't practically optimise everything completely and there is an upper limit on the cpu resources available.
 
 There are other vague issues like not saying how big the document is when you measure if it's able to keep up. A text editor that is designed for editing large documents will be able to insert and delete text in the middle without CopyMem()'ing the rest of the document around every time you type a character. On windows I regularly edit text files 100's of megabytes in size.

[psxphill]

I thought it was obvious to you that Amiga software should not use busy loops when doing nothing.

When making a statement that the ONLY thing important with performance of a text editor is it can keep up with typing speed then it's actually not obvious at all. If you are making assumptions about what the statement really means, then you're agreeing with something without actually understanding the point it's making.

By saying there are loads of little implied things that we have to know, then making the statement in the first place is irrelevant as it's trying to say there is only one thing you have to know.
 
 Ed isn't fast enough.

[psxphill]

There must have been a reason why TRIPOS was picked for the Amiga, other than there was time pressure and not many other options were available then.

 I think the main consideration was that it was quick to graft it onto exec. If they'd had to wait a long time then they may as well have developed CAOS.
 
 It probably was the only 68000 operating system that they could have used.

[psxphill]

I've been told that the weird design was actually thought through: it was to reduce the risk on mechanical typewriters with the next letter getting stuck on the returning previous letter.

well there are two reasons listed on Wikipedia http://en.wikipedia.org/wiki/QWERTY#History_and_purposes
 
 reduce jams and trying to distribute letters evenly.

[psxphill]

Don't care about the code time for me : I just want PERFECT code...

Sometimes I can think many days about one small routine to find finally his Truth... Just like SpeedGeek with CopyMem & CopyMemQuick !

Sure we've all been there. If you can write something the fastest possible then it feels good. If you ever get the ambition to work on something bigger then you will run out of time pretty quick.

 I try to balance optimising algorithms and code quality and have the compiler worry about what registers to use etc.