[kqr]

All of your slash examples represent either–or situations. A swich turns it on or off, the situation is a win in the first outcome or a win in the second outcome, etc.

It's true that key–value store shouldn't be written with a hyphen. It should be written with an en dash, which is used "to contrast values or illustrate a relationship between two things [... e.g.] Mother–daughter relationship"

https://en.wikipedia.org/wiki/Dash#En_dash

I just didn't want to bother with typography at that level of pedanticism.

[VerifiedReports]

No, they don't. A master/slave configuration (of hard drives, for example) involves two things. I specifically included it to head off the exact objection you're raising.

"...the slash is now used to represent division and fractions, as a date separator, in between multiple alternative or related terms"

-Wikipedia

And what is a key/value store? A store of related terms.

And if you had a system that only allowed a finite collection of key values, where might you put them? A key-value store.

[kqr]

The hard drives are either master or slave. A hard drive is not a master-and-slave.

[VerifiedReports]

Exactly. And an entry in a key/value store is either a key or a value. Not both.

[kqr]

No, an entry is a key-and-value pair. Are you deriously suggesting it is possible to add only keys without corresponding values, or vice versa?