> where on earth did the hash # key come from? It had no use in typewriter days, did it?
What you call the hash key (#) is actually a proofreading mark, and represents a space. In the US, we also call it the pound sign. When I was a young lad (more than a couple of months ago!) I learned in elementary school to use the # sign for pounds (as in weight, not money.) And there was a difference if we used it ahead of the number rather than after it. 30# was an abbreviation for 2 stones 2 pounds, but #30 was something else, and for the life of me I cannot remember. It may have meant "number" but I can't figure out a context where that would be necessary. Got to thinking about it. #1 was a shortcut for "number one" so #30 would mean "number 30" in a list of 30 or more items.
Interestingly, my at-work dictionary does not give anything for hash as a mark like #, and says that hash mark is a slang for a service stripe on a military member's sleeve. In our military I believe only the Navy uses them to indicate years of service, with each hash makr representing five years of service.
