Gary Arlen Kildall ( / ˈ k ɪ l d ɔː l / ; May 19, 1942 – July 11, 1994) was an American computer scientist and business owner who worked with early computers. In the 1970s, Kildall developed the operating system CP/M and other tools for programming computers. He later started a company called Digital Research, Inc. to sell his software. Kildall is recognized as an important figure in the development of personal computers.

In 1974 in Pacific Grove, California, Kildall showed the first working version of CP/M, which later became a widely used operating system for microcomputers. Along with his creation of the BIOS (Basic Input Output System), his operating system enabled computers that use microprocessors to interact with disk storage. Kildall was one of the first people to see microprocessors as complete computers. In the 1980s, Kildall also appeared on PBS as a co-host of Computer Chronicles, a weekly show that shared information about new advances in personal computing.

Early life

Gary Kildall was born and raised in Seattle, Washington, where his family ran a school that taught people about ships and sailing. His father, Joseph Kildall, was a ship captain of Norwegian heritage. His mother, Emma, had part Swedish ancestry because Kildall’s grandmother was born in Långbäck, Sweden, in Skellefteå Municipality, but she moved to Canada when she was 23 years old.

Kildall earned a degree in mathematics in 1967 and a degree in computer science in 1968, both from the University of Washington. At first, he wanted to become a math teacher. However, during his studies, he became more interested in computers and decided to pursue a Ph.D. in computer science.

To fulfill his military service requirement, Kildall taught at the Naval Postgraduate School in Monterey, California.

Kildall briefly returned to the University of Washington and completed his doctorate in computer science in 1972.

Intel provided him with systems that used the 8008 and 8080 processors. In 1973, he created the first high-level programming language for microprocessors, called PL/M. For Intel, he also developed tools named INTERP/8 and INTERP/80 to simulate the 8008 and 8080 processors. That same year, he designed an operating system called CP/M to allow the 8080 processor to control a floppy disk drive. This system combined all the main parts of a computer into a microcomputer for the first time. Kildall showed CP/M to Intel, but Intel was not interested in it and instead chose to promote PL/M.

Business career

In 1973, Kildall and Kathryn Strutynski created the PL/M language to develop CP/M, one of the first operating systems for personal computers. They used their experience with IBM mainframe computers and the VM operating system as a reference.

Kildall and his wife, Dorothy, started a company called "Intergalactic Digital Research" (later renamed Digital Research, Inc.) to sell CP/M through advertisements in hobbyist magazines. Digital Research licensed CP/M for the IMSAI 8080, a popular copy of the Altair 8800. As more companies used CP/M, it became the standard operating system and needed to support many different types of computer hardware. To solve this, Kildall introduced the BIOS, a set of simple programs stored in computer hardware (ROM or EPROM microprocessor) that allowed CP/M to work on different systems without changes.

CP/M's fast success surprised Kildall, and he was slow to update it for high-density floppy disks and hard drives. After hardware companies discussed making a competing operating system, Kildall began a project to develop CP/M 2. By 1981, CP/M was used on 3,000 different computer models, and Digital Research, Inc. earned $5.4 million in yearly revenue.

Between 1983 and 1984, Digital Research provided several business and educational programs for the IBM PC on bootable floppy disks bundled with SpeedStart CP/M, a simplified version of CP/M-86.

In 1980, IBM asked Digital Research to buy a version of CP/M called CP/M-86 for the IBM PC, based on Bill Gates' suggestion. Gary Kildall left initial talks to his wife, Dorothy, as he often did, while he and Tom Rolander, a developer of MP/M, used Gary’s private airplane to deliver software to Bill Godbout. Before IBM explained their purpose, they asked Dorothy to sign a non-disclosure agreement. Dorothy refused without Gary’s approval, as advised by DRI attorney Gerry Davis. Gary returned later and tried to continue the discussion with IBM. Accounts differ on whether he signed the agreement or met with IBM representatives.

Several reasons are given for the failed deal. DRI might have been unwilling to sell CP/M-86 for a one-time payment instead of its usual royalty-based plan. Dorothy might have believed the company could not deliver CP/M-86 on IBM’s schedule, as it was busy developing PL/I for Data General. IBM representatives might have been frustrated by what they saw as a routine formality. Kildall claimed IBM representatives took the same flight to Florida as he and Dorothy for their vacation and reached a handshake agreement. IBM’s main negotiator, Jack Sams, said he never met Gary, though he admitted someone else in his group might have been on the flight. He returned to Seattle to talk with Microsoft again.

Sams told Gates, who had already agreed to provide BASIC and other programs for the IBM PC, that Gary “went flying” unexpectedly. Sams asked Gates to find an operating system, and Gates later suggested using 86-DOS, a system that used Kildall’s CP/M application programming interface, from Seattle Computer Products. Paul Allen negotiated a license with SCP, adapted 86-DOS for IBM hardware, and IBM released it as IBM PC DOS.

Kildall received a copy of PC DOS, studied it, and believed it copied CP/M. When he asked Gerry Davis about legal options, Davis said software intellectual property laws were unclear enough to sue. Kildall only threatened legal action, and IBM offered to sell CP/M-86 as an option for the PC in exchange for liability release. Kildall accepted, thinking IBM’s new system would not succeed. When the IBM PC launched, IBM sold PC DOS as an unbundled option priced at $40. Most software required PC DOS, and without it, the IBM PC relied only on its built-in Cassette BASIC. CP/M-86 was released later at $240 and sold poorly compared to DOS.

After losing the IBM deal, Gary and Dorothy faced pressure to bring in more experienced management, and Gary’s influence declined. He worked on projects like MP/M, a multitasking version of CP/M, and an implementation of the Logo programming language, which he hoped would replace BASIC in education but did not.

In 1985, Digital Research developed FlexOS, a modular real-time multiuser multitasking operating system (RTOS).

After seeing the Apple Lisa, Kildall oversaw the creation of DRI’s graphical user interface, Graphics Environment Manager (GEM), introduced on February 28, 1985. Novell acquired DRI in 1991, earning millions for Kildall.

Kildall resigned as CEO of Digital Research on June 28, 1985, but remained chairman of the board.

Kildall co-hosted a PBS program called Computer Chronicles, discussing personal computing trends. He co-hosted for seven years during the first eight seasons (1983–1990). The program continued through its 19th season, ending on June 25, 2002.

In 1984, Gary started Activenture, adapting optical disc technology for computers using the Red Book developed by Sony and Philips in 1980. In 1985, Activenture was renamed KnowledgeSet.

In June 1985, Activenture released The Electronic Encyclopedia, a CD-ROM version of Grolier’s Academic American Encyclopedia. It became the first computer encyclopedia and added pictures in 1990, audio and video in 1992. The encyclopedia was acquired by Banta Corporation, with its last CD-ROM version published in 2003.

Kildall’s final business venture, Prometheus Light and Sound (PLS) in Austin, Texas, developed a modular PBX communication system called "Intelliphone" to connect land-line telephones with mobile phones and home appliances. The system included a UUCP-based store-and-forward system for email and file exchange between nodes and planned to support TCP/IP later.

According to Brian Halla, an Intel liaison to Digital Research in the 1970s, Gary Kildall showed him a VAX 11/780 computer running a simulation of a spinning Coke bottle in his home. Halla said Kildall sold the computer to Pixar a few months later.

Computer Connections

In 1992, Kildall was invited to the University of Washington computer science program's 25th anniversary event. As a respected graduate of the program, Kildall felt upset when asked to attend only as a guest. He was also upset that the main speech was given by Bill Gates, a Harvard University dropout who had donated money to UW but had never been a student there.

In response, Kildall began writing a memoir titled Computer Connections: People, Places, and Events in the Evolution of the Personal Computer Industry. The memoir, which Kildall wanted to publish, described his frustration that people did not seem to value elegant computer software.

Kildall wrote, "Do not think for a minute that [Bill] Gates made it 'big time' because of his technical skills." He described Gates as "more of an opportunist than a technical type, and severely opinionated, even when the opinion he holds is absurd."

In an appendix, Kildall called DOS "plain and simple theft" because its first 26 system calls worked the same as CP/M's. He accused IBM of creating a price difference between PC DOS and CP/M-86 to reduce CP/M's importance.

Kildall finished a rough draft of the manuscript by the end of 1993, but the full text was never published. Journalist Harold Evans used the memoir as a source for a chapter about Kildall in the 2004 book They Made America, stating that Microsoft had taken Kildall's inventions. IBM employees involved in the PC project disagreed with the book's account, and Microsoft called it "one-sided and inaccurate."

In August 2016, Kildall's family made the first seven chapters of Computer Connections available as a free public download.

Personal life

Kildall described himself as a "greaser" during high school. His colleagues remembered him as creative, easygoing, and adventurous. He enjoyed flying, sports cars, auto racing, and boating. He had a lifelong love for the ocean.

He thought about making a cassette tape of the "IBM Flying Story." He planned to carry copies in his jacket to share with others. However, a problem arose. After he told the story, people often asked, "Did you actually go flying and cause IBM to lose the deal?"

Kildall preferred to focus on his work before and after the IBM event rather than the incident itself. However, people often compared him to Bill Gates, and some forgot about his contributions. A story grew around the important IBM-DRI meeting, fueled by Gates and journalists, which claimed Kildall had irresponsibly taken the day off for a fun flight.

Later in life, Kildall privately felt upset about being overshadowed by Microsoft. He also struggled with alcoholism.

Selling DRI to Novell made Kildall wealthy. He moved to West Lake Hills, a suburb of Austin. His home in Austin was a lakeside property with spaces for several sports cars and a video studio in the basement. He owned and flew his own Learjet and had at least one boat on the lake. In Austin, he volunteered to help children with HIV/AIDS. He also owned a large house with an ocean view in Pebble Beach, California, near the former headquarters of DRI.

Death and legacy

On July 8, 1994, Gary Kildall, who was 52 years old, got a head injury at the Franklin Street Bar & Grill, a bar in Monterey, California. The exact cause of the injury is not known. Some sources say he fell from a chair, fell down steps, or was attacked because he was wearing Harley-Davidson clothing. Harold Evans, in the book They Made America, wrote that Kildall "stumbled and hit his head" inside the bar and "was found on the floor."

After the injury, Kildall was sent home from the hospital twice. He was declared dead at the Community Hospital of the Monterey Peninsula on July 11, 1994. An autopsy done on July 12 did not clearly explain the cause of death. Evans said that Kildall’s head injury caused a brain bleed, which led to a blood clot inside his skull. A CP/M Usenet FAQ said Kildall had a concussion from the injury and died of heart failure. The connection between the injury and heart failure is not clear. The autopsy also found evidence of long-term alcohol use.

At first, news reports and police thought Kildall’s death might be a murder. The coroner’s report said his injury could have been caused by someone else, and the case was sent to the Monterey Police Department. Police Sgt. Frank Sollecito said, “We’re going to investigate it as a possible homicide,” but added, “I’m not going to flat-out say it’s a homicide.”

Kildall’s body was cremated. His remains were buried in Evergreen Washelli Memorial Park in north Seattle.

After Kildall’s death, Bill Gates said he was “one of the original pioneers of the PC revolution” and “a very creative computer scientist who did excellent work.” He added, “Although we were competitors, I always had tremendous respect for his contributions to the PC industry. His untimely death was very unfortunate, and his work will be missed.”

Stewart Cheifet, Kildall’s co-host on Computer Chronicles, said Kildall was his “favorite guy” and praised his skills and contributions to personal computing. He also said, “Gary’s problem was that he was too much of a gentleman. He wasn’t a killer business kind of guy,” and added that Kildall was “a decent man in a business that was hard to succeed in if you were decent.”

In March 1995, the Software Publishers Association (SPA) honored Kildall after his death for his work in the microcomputer industry:

• Created the first programming language and compiler for microprocessors called PL/M (1973).
• Developed CP/M, the first microprocessor disk operating system, which sold over 250,000 copies (1974).
• Designed the first successful open system architecture by separating hardware interfaces into BIOS routines (1975).
• Created early diskette track buffering schemes, read-ahead algorithms, file directory caches, and RAM drive emulators.
• Introduced operating systems with multitasking, windowing, and menu-driven user interfaces (with Digital Research): MP/M, Concurrent CP/M, Concurrent DOS, DOS Plus, GEM.
• Developed XLT86, the first binary recompiler (1981).
• Created the first computer interface for video disks to allow automatic nonlinear playback, a precursor to today’s interactive multimedia (1984, with Activenture).
• Designed the file system and data structures for the first consumer CD-ROM (1985, with KnowledgeSet).

In April 2014, the city of Pacific Grove placed a commemorative plaque outside Kildall’s former home, which also served as the early headquarters of Digital Research.

In popular culture

Steve Hauk wrote a play titled A Mild Concussion. Later, Steve Hauk worked with Stewart Cheifet to write a second version of the play, which was given the title The Forgotten Computer Genius. The play explores the final days of a computer genius.