IBM Butterfly keyboard
Sliding keyboard that expands from compact to full size.
The IBM Butterfly keyboard, officially known as the TrackWrite keyboard, is a sliding keyboard design used in the IBM ThinkPad 701 subnotebook. It is notable for its innovative mechanism that allows the keyboard to expand from a compact width when closed to a full-sized keyboard when open, achieved by two triangular pieces that slide outward and mesh together. This design earned the 701 the colloquial name 'Butterfly' and contributed to it becoming the most sold laptop in 1995.
- Developed from
- 1993
- Sold from
- March 1995
- Price range
- $1,499 to $3,299
- Design awards
- 27
- Processors
- Intel i486 DX2 or DX4
- Graphics chip
- CT-65545
- Keyboard width when open
- 29.2 cm (11.5 in)
Lore & Background
The keyboard was designed by John Karidis, Sam Lucente, and Robert Tennant, with Richard Sapper responsible for the overall ThinkPad design. The concept began as a photocopy of a keyboard in spring 1993, followed by a plexiglass prototype in summer. The decision to fund the notebook was made in fall 1993, with introduction planned a year later, but delays meant it used the Intel 486 instead of the faster Pentium. The keyboard is split into two roughly right triangle pieces that slide as the laptop's lid is opened or closed, driven by a cam on the lid's hinge so motions are synchronized. The 701 was codenamed 'butterfly' internally, but IBM's legal department did not allow names of living creatures for products. After announcement, IBM received a legal threat about the name 'butterfly' from someone known only as George, claiming trademark violation on a supercomputer product named Butterfly; IBM replied they did not plan to use it as a brand name, and no further action occurred.
Reader's Guide
The ThinkPad 701 was discontinued per December 21, 1995, because newer laptop models contained larger screens, making the folding keyboard unnecessary. Other companies were also moving to Pentium processors. The 701 series has been described as a product with innovative features well received in the market, but the total package missed the competitive mark. For the 10th anniversary of ThinkPad in 2002, IBM Japan produced a 65% scale model kit of the 701. In 2003, ZDNet reported that the IBM Design Center was experimenting with new laptop models including a butterfly keyboard, and David Hill stated he tried to bring back the design but could not. In 2021, Lenovo filed a patent for a similar keyboard. The laptop is displayed in the design collection of the Museum of Modern Art in Manhattan, Die Neue Sammlung in Munich, and the Computer History Museum. It was briefly shown in the 1995 James Bond film GoldenEye, Blood Diamond, and Mission: Impossible.
The Buckling Spring Legacy
The IBM PC keyboard ecosystem, standardized across the original machine and its countless compatibles, underwent more than three decades of iterative refinement as PC architecture evolved. At the heart of this lineage sits the Model M, a keyboard class first introduced in 1984 and produced not only by IBM itself but also by Lexmark, Maxi Switch, and Unicomp. What distinguishes the Model M from most of its contemporaries is its buckling spring key mechanism, a tactile design that gave each keystroke a satisfying mechanical resistance before the key bottomed out. Beyond the switch technology, many Model M units featured fully swappable keycaps, allowing users to reconfigure labels or replace worn legends without discarding the entire board. This combination of durable mechanical engineering and user-serviceable components made the Model M a benchmark for typing feel in an era when keyboard design was still being defined. Its influence persists, as the vast majority of modern keyboards still trace their physical and logical design back to the principles established by this 1984 release.
A Layout That Divided Opinion
The 1981 IBM PC keyboard generated a remarkably polarized response from both reviewers and end users. PC Magazine commended the overall hardware construction yet openly questioned how a company with IBM's deep expertise in keyboard manufacturing could position the left Shift key at such an awkward reach. By 1982, the magazine's reader-submitted Wish List column received more letters requesting a way to check the status of the three lock keys than on any other topic. Byte columnist Jerry Pournelle captured the contradiction in a single phrase, calling the board infuriatingly excellent. He lauded the tactile feel while simultaneously lamenting that the placement of Shift and neighboring modifiers was enough to make a saint weep. He also noted that science-fiction editor Jim Baen was nearly driven to distraction by the layout, and that many of Baen's contributing authors refused to work with the keyboard at all, leaving them unable to submit manuscripts in a compatible format. IBM's own Don Estridge acknowledged in 1983 that he was not thrilled with the left Shift and Return placements, yet argued that no consensus existed and that changing the layout after launch would create far greater problems.
The Model M's Shadow Over Modern Keyboards
Because the IBM PC layout, and the Model M in particular, became the de facto standard, nearly every keyboard produced today is some variant of that 1984 design. This dominance has created persistent friction for software originally designed around alternative keyboard geometries. The vi text editor, for instance, relies heavily on the Escape key. On the ADM-3A terminal where vi was developed, that key sat where the Tab key now resides on a PC; on the IBM layout it was pushed to a corner, forcing users to remap Caps Lock as a workaround. The Emacs editor presents an even more complex case. Emacs makes extensive use of modifier keys and favors the Control key over the Meta key, a convention inherited from the Knight keyboard, where Control sat inside Meta. The Model M reversed that relationship, placing Control outside Alt. The space-cadet keyboard went further, arranging all four modifier keys in a single row to facilitate chording. On the Model M layout, reaching those modifiers often demands the pinkie, giving rise to what the community calls the Emacs pinky problem. Over the decades, additional keys for power management, volume, media transport, and application shortcuts have been layered on top, but the underlying geometry remains stubbornly Model M.
Inherited from the Typewriter and the Teletype
The PC keyboard did not emerge from a blank page; its key set is a palimpsest of earlier input technologies. Several core keys trace directly to mechanical typewriters. Backspace originally pushed the carriage one position backward; on video-display computers it deletes the character at the cursor. Tab advances to the next tab stop. Enter, labeled CR or Return on ASCII boards, wraps the line or activates a selected option, echoing the typewriter's carriage-return lever. Caps Lock and Shift both select uppercase characters, but on a typewriter the Shift was a physical lever that moved the typebars, while Caps Lock added a mechanical latch to hold that lever depressed until Shift was pressed again. The space bar simply inserts a gap between characters. Other keys carry the imprint of the teletypewriter: Esc produces an ASCII escape character for exiting modes; the backtick, tilde, and circumflex were originally accents backspaced over base letters for non-English text; the asterisk, underscore, and vertical bar (known in Unix as the pipe) served typographic and programming roles. The Control key shifts letters and numbers out of the ASCII graphics range. Some later additions, such as dedicated function keys, were introduced by operating-system and GUI vendors like Microsoft and became factory defaults.
Frequently Asked Questions
What is the IBM Butterfly keyboard?
The Butterfly keyboard is the official name for the TrackWrite sliding-keyboard mechanism that IBM built into the ThinkPad 701 subnotebook. It lets a very narrow, portable deck open out into a standard full-width typing surface.
How does the Butterfly sliding mechanism actually work?
Two triangular half-boards sit side by side in the closed position and then slide outward along a track, interlocking like puzzle pieces to form a complete full-size keyboard. This meshing action is what gives the design its distinctive butterfly-wing motion.
Why did people start calling the ThinkPad 701 the 'Butterfly'?
The nickname came directly from watching the two triangular key-plates spread apart like wings when you opened the deck. It stuck as the model's most recognizable shorthand in the enthusiast community.
What hardware did the ThinkPad 701 ship with?
It was offered with either an Intel i486 DX2 or DX4 processor and used a CT-65545 graphics chip. Pricing ranged from $1,499 up to $3,299 depending on configuration, and it hit stores in March 1995.
How did the ThinkPad 701 perform commercially and in the design world?
It became the best-selling laptop of 1995, a remarkable result for a subnotebook priced in the mid-thousands. The design also racked up 27 design awards, cementing its reputation as one of the most innovative portable-computing products of the mid-'90s.
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