The code that generates the little diagrams on my station pages like this one is written in PostScript. Well, to be strict, it’s PS generated by a Haskell program and exactly why it’s that way is probably a question for @Ben Harris who wrote the code during one of our station collecting holidays.

Anyway, today I noticed it had stopped working. "Last OS error: Permission denied” says Ghostscript on running the code. And yet, stracing the whole thing, nowhere is an EACCES to be seen. Turns out Ghostscript has made default a “safe mode” which restricts PostScript file operations to only those files you specify in advance. You can get around it by adding -dNOSAFER to the gs command line. Fine, whatever.

But what I definitely object to is Ghostscript sounding like it’s reporting an ordinary OS-level system call error, when in fact it’s reporting its own MADE UP ERROR. They could at least have had the decency not to call it an “OS error”. Grr.