It's an interesting idiom you see in hpc and scientific computing that can be jarring when first encountered. "Codes" can be read as program or library.
No, that is more national lab slang.
hey, can you make some viewgraphs about the new dynamics codes?
yeah sure. I just need a cost center and program code to charge my time to...
It's just a bit antiquated. Rest assured people were writing codes for decades before any consumers had computers