This wasn't, however, the first HP machine to use 3.5" Sony floppies. I'm afraid I can't remember the model name offhand. Four digits, beginning with a 9, I think.
It was billed as a computer, not a calculator.
It came out circa 1983, maybe late 1982. It cost about $10,000 with 65K of RAM. It had a full bitmap-addressable CRT screen and built-in IEEE-488 interface. It was based on a 68000 processor, and aimed at the scientific and engineering market. It used a very nice, very sophisticated version of BASIC with all the usual control structures, optional line numbers, etc. Programs executed at very, very roughly 1000 lines of BASIC per second. A dual-floppy unit was the main form of storage; I don't believe a hard drive was a common option.
Oh, and it supported version of Context MBA, the now-forgotten program which completely out-featured 1-2-3 but had been written in Pascal and was therefore unusably slow on a PC, though perfectly acceptable on this HP machine.