Compound nouns in plural

youssefdirin plural do these 2 forms differ?"computer disks""computers disks"

Yes: the second is incorrect.

youssefdirI feel in the first there's one computer, but in the second there are many computers with many disks.

No, that is a misconception.

youssefdir"what to say when each computer has only 1

If there are many computers and each has one or more disks (doesn't matter) use 'computer disks', if there is one computer with one disk then 'computer disk' and if there is one computer with 2 or more disks you could say 'those are the computer disks'.

In your sentence the word 'computer' (which is a noun) acts as an adjective (it describes the type of disc), therefore it is single, as a

I got your point.
I would like to discuss "the computer disks" versus "computer disks"; the definite article "the" strengthens the "noun" effect in "computer" over its adjective meaning?

youssefdirI would like to discuss "the computer disks" versus "computer disks"; the definite article "the" strengthens the "noun" effect in "computer" over its adjective meaning?

No, not at all; the function of the articles are unrelated. 'The' marks specific disks or previously mentioned disks.

so because of "the" or "many" the disks are specified, and when they are then the "computer" is single and we omit the possibility of many computers?!

youssefdirbecause of "the" or "many" the disks are specified, and when they are then the "computer" is single and we omit the possibility of many computers?!

We do not omit the possibility of many computers. In English, we do not indicate number in adjectives, that is all.

youssefdirso because of "the" or "many" the disks are specified, and when they are then the "computer" is single and we omit the possibility of many computers?!

The determiner has nothing two do with it. Chipw has explained that 'computer' functions adjectivally here.

A brown coat. Two brown coats
A brick wall. Two brick walls