You missed calculators and there are rough catagories:
First eletronic calc
first pocket calc
HP35 $700, the lowcost market breaker being the Bomar Brain.
First programable calc
<first personal computer (I think I know that one)
If you mean PC (as in the IBM PC) then the answer is IBM. However if you
man pc as in personally owned computer, then you go back by maybe 10-20
years to things like old surplus missle computers, homebrewed systems and
PDP-8s and the like. Prior to the IBM abortion pc meant personally owned
and was not based on what it was but who owned it. Personally owned
computers was a new thing starting in the late 60s to early 70s. Around
72-73 it was possible to buy a used PDP-8 or CM2000 for a few thousand
dollars. I know in December of 72 I almost bought a Cincinati Millicron
CM2000 for the offered price of $2000(big bucks then) with 8k of core,
serial line card and 6port muxed serial card.
<first portable computer
Define portable as I'd seen totables in the late 70s. One very nice one
was an expanded EVK68 board in a classy wood case with a small crt and
keyboard.
One that comes to mind was the HP(5100?) complete packaged system with
tape for storage and basic and GPIB for external interface.
<first laptop
Not sure but it wasnt a dos based for sure. Tandy trs100 or the similar
NEC, Epson, and others.
<first GUI
Xerox PARC smalltalk
<first OS
This is real old likely in the late 40s early 50s and was likely a
machine monitor system to load/save programs. Even the PDP-1 had an OS
to timeshare multiple users. You may have to be more specific as to tthe
type or style of OS as there are several and the appearance of each
corosponds to emerging concepts in computing.
Allison