[mananaysiempre]

There seems to be a pattern of humorous plurals in English where by analogy with ox ~ oxen you get -x ~ -xen: boxen, Unixen, VAXen.

Before you call this pattern silly, consider that the fairly normal plural “Unices” is by analogy with Latin plurals in -x = -c|s ~ -c|ēs, where I’ve expanded -x into -cs to make it clear that the Latin singular comprises a noun stem ending in -c- and a (nominative) singular ending -s, which does exist in Latin but is otherwise completely nonexistent in English. (This is extra funny for Unix < Unics < Multics.) Analogies are the order of the day in this language.

[bayindirh]

Yeah. After reading your comment, I thought "maybe the Xen hypervisor is named because of this phenomena". "xen" just means "many" in that context.

Also, probably because of approaching graybeard territory, Thinking about boxen of VAXen running UNIXen makes me feel warm and fuzzy. :D