- of
How the HP-35 Calculator Killed the Slide Rule and Made an IT Giant
by Chris Preimesberger
1972:
The new HP-35, the world's first handheld scientific calculator, virtually made the engineering slide rule obsolete. It was HP's first product to contain both integrated circuits and LEDs. Both technologies had been developed in HP Labs.
1977: HP-01 Wrist Instrument:
Combination digital wristwatch, calculator and personal calendar. Performed more than three-dozen functions to manipulate and interrelate time, calendar and numeric data. It demonstrated HP's excellence at miniaturization.
1981: HP-12C:
HP's longest and best-selling calculator. The HP-12C sold today acts and looks just as it did when first introduced in 1981, with the exception of improved performance due to modern components. Valued for its reliability, proven accuracy and long battery life, the HP-12C has become an industry standard in the business and finance community.
1986: HP-18C:
First calculator with HP Solve. HP Solve is an HP calculator differentiator that lets users solve an equation for any variable without rewriting the equation. The HP-18C was also the first calculator with infrared printing and with menu-driven soft keys for better usability.
1989: HP-48SX:
First handheld calculator with two-way infrared communication.
1991: HP 95LX palmtop computer:
Largely leveraging HP's calculator technology, the HP 95LX had as much computing power as a desktop PC and was able to run many standard DOS programs. It had a financial calculator, telephone number/address program, simple text editor and infrared link for transferring data. Widely considered HP's first PDA (personal digital assistant), it was the first palmtop PC with built-in Lotus 1-2-3.
1993: HP 48gx:
Was a sophisticated scientific-graphics calculator featuring 3-D plotting and other advanced built-in features not previously found in calculators.
1999: HP 30s:
This scientific algebraic calculator had an an interchangeable keypad overlay so users could change the calculator's color.
2003: HP 12c Platinum:
An enhanced version of the HP 12c financial calculator, the HP 12c Platinum boasts increased memory to allow for more keystroke programming steps and offers more built-in functions, including the option of standard algebraic mode, as well as Reverse Polish Notation mode.
2003: HP 49g+:
This was the first handheld calculator to offer expansion via Secure Digital cards.
Desktops and Notebooks News & Reviews 
iPad 3: 10 Design Ideas Apple Should Borrow
10 Hot Tech Products Sure to Fire Up the Market in 2012
iOS, Android App Economy Fuel 500K U.S. Jobs: TechNet
Microsoft's Windows 8 Minimized Ribbon, Sensors Among New Feature[..]
NoSQL Database: 5 Ways to Make It Enterprise-Ready
Facebook IPO: 10 Facts You Didn't Know Before the SEC Filing
See All Slideshows
In the early 1970s, the slide rule was standard equipment for students, engineers and scientists. The personal computer was still a twinkle in the eyes of the visionaries. Then, in 1972, Hewlett-Packard introduced the world's first scientific pocket calculator—the HP-35—and delivered portable "computing power" into the hands of users. An instant hit among scientists and engineers, the HP-35 soon displaced slide rules and marked the birthplace of HP's innovative and highly successful heritage in the handheld calculator market.
On the next several pages are some of the major innovations in the portable calculator world that were contributed by HP. It all started on a direct request from William Hewlett himself, with the only qualification being that "it fits in my shirt pocket." Dave Cochran, the original HP-35 product manager, said on April 14 that he sometimes wanted to tell Mr. Hewlett's tailor "to enlarge his pockets and not tell him."