[tharkun__]

Externally visible stuff: definitely. You really need something like TeX or by now Linux and some GNU Tools etc. to stand the test of time.

My very first job was to work on the backend of some software for internal use. You have probably all bought products that were "administered" in said software. When I worked on it it was 15 years old. It evolved over this time of course but original bits and pieces were all around me. And I evolved bits and pieces of it as did others. By now it's been another 15 years and while I know they did a rewrite of some parts of the system I bet that some of both my code and the code I found to have been written almost 15 years before I started there is still around and you and me keep buying products touched by that software without knowing. The rewrite was also done by at least one person that was around when the original was built. He learned a new language to implement it.ut he took all of his domain and business logic knowledge over.

Its even more funny because I knew the guy that wrote some of the code I worked with directly from a different company but I had no idea he worked there or that he worked in that project until I saw his name in the CVS history. Yes CVS. I personally moved it to SVN to "modernize". I hope that was recognized as "technical debt" and they moved to git but I wouldn't know.