Fifty Years of the Personal Computer Operating System
=====================================================
By David Laws, April 18, 2024

PC software pioneer Gary Kildall demonstrated CP/M, the first
commercially successful personal computer operating system in Pacific
Grove, California, in 1974. Following is the story of how his
company, Digital Research Inc., established CP/M as an industry
standard and its subsequent loss to a version from Microsoft that
copied the look and feel of the DRI software.

Early Days
==========
Gary Arlen Kildall was born to a family of Scandinavian descent in
Seattle, Washington, in 1942. His inventive skills flourished in
repairing automobiles and having fun but suffered in scholastic
pursuits. He qualified for admission to the University of Washington
based on his teaching experience at the family-owned Kildall Nautical
School rather than his high school grades.

Dorothy and Gary, circa 1978. Photo: Courtesy Kildall Family
<https://computerhistory.org/wp-content/uploads/2016/08/
gary-kildall-gary-dorothy-1978.jpg>

Gary entered college and married his high school sweetheart Dorothy
McEwen in 1963. He was one of 20 students accepted into the
university's first master's program in computer science. Here, his
mathematical talents were applied to a subject that fascinated him:
all-night sessions programming a new Burroughs computer. To avoid the
uncertainty of the draft at the height of the Vietnam War, on
graduating with a PhD, he entered a US Navy officer training school
and was posted to serve as an instructor in computer science at the
Naval Postgraduate School (NPS) in Monterey, California.

Herrmann Hall, Naval Postgraduate School, Monterey. Creative Commons
CC0 1.0 Universal Public Domain Dedication.
<https://computerhistory.org/wp-content/uploads/2024/04/
Herrmann-Hall-Naval-Post-Graduate-School.jpg>

Gary remained at NPS as an associate professor after his tour of duty
ended in 1972. He became fascinated with Intel Corporation's first
microprocessor chip and simulated its operation on the school's IBM
mainframe computer. This work earned him a consulting relationship
with the company to develop PL/M, a high-level programming language
that played a significant role in establishing Intel as the dominant
supplier of chips for personal computers.

To design software tools for Intel's second-generation processor, he
needed to connect to a new 8" floppy disk-drive storage unit from
Memorex. He wrote code for the necessary interface software that he
called CP/M (Control Program for Microcomputers) in a few weeks, but
his efforts to build the electronic hardware required to transfer the
data failed. The project languished for a year. Frustrated, he called
electronic engineer John Torode, a college friend then teaching at UC
Berkeley, who crafted a "beautiful rat's nest of wirewraps, boards
and cables" for the task.

This is going to be a "big thing"
=================================
Late one afternoon in the fall of 1974, together with John Torode, in
the backyard workshop of his home at 781 Bayview Avenue, Pacific
Grove, Gary "loaded my CP/M program from paper tape to the diskette
and 'booted' CP/M from the diskette, and up came the prompt: *."

"This may have been one of the most exciting days of my life, except,
of course, when I visited Niagara Falls," he exclaimed. We now have
the power of an IBM S/370 [mainframe computer] at our fingertips."
This is going to be a "big thing," they told each other and "retired
for the evening to take on the simpler task of emptying a jug of
not-so-good red wine ... and speculating on the future of our new
software tool."

By successfully booting a computer from a floppy disk drive, they had
given birth to an operating system that, together with the
microprocessor and the disk drive, would provide one of the key
building blocks of the personal computer revolution. While they knew
it was important, neither realized the extraordinary impact it would
have on their lives and times.

781 Bayview Avenue, Pacific Grove, circa 1974. Photo: Courtesy
Kildall Family
<https://computerhistory.org/wp-content/uploads/2024/04/
Kildall-home.jpg>

As Intel expressed no interest in CP/M, Gary was free to exploit the
program on his own and sold the first license in 1975. He continued
teaching part-time at NPS, and in 1976, with his wife Dorothy as
cofounder, they established Intergalactic Digital Research to pursue
commercial opportunities. They shortened the company name to Digital
Research Inc. (DRI) when it became available.

Glenn Ewing, a former NPS student, approached DRI with the
opportunity to license CP/M for a new family of disk subsystems for
fast-growing microcomputer maker IMSAI Inc. Reluctant to adapt the
code for another controller, Gary worked with Glen Ewing to split out
the hardware dependent-portions so they could be incorporated into a
separate piece of code called the BIOS (Basic Input Output System).

Before CP/M, computer manufacturers designed their operating systems
to work only with their own hardware and peripheral equipment. An IBM
OS would only work with IBM computers; a Burroughs OS would only work
with Burroughs computers, etc. Applications had to be written for
each computer's specific OS. Such "closed systems" made it difficult
or impossible to mix and match the best pieces of equipment and
software applications programs from different manufacturers.

The BIOS code allowed all Intel and compatible microprocessor-based
computers from other manufacturers to run CP/M on any new hardware.
This capability stimulated the rise of an independent software
industry by expanding the market's potential size for each product. A
single program could run without modification on computers supplied
by multiple manufacturers, laying an essential foundation for the
personal computer revolution.

DRI advertisement from 1978
<https://computerhistory.org/wp-content/uploads/2024/04/
DRI-ad-1978.png>

Dorothy and Gary opened their first office at 716 Lighthouse Avenue,
Pacific Grove, on the upper floor, with a view of Monterey Bay. They
sold CP/M disks via mail order and walked to the post office every
workday to pick up checks resulting from ads placed in industry
magazines such as Byte and Dr. Dobbs' Journal of Computer
Calisthenics and Orthodontia.

A licensing deal with computer manufacturer IMSAI bestowed
credibility across the industry. CP/M became accepted as a standard
and was offered by most early personal computer vendors, including
pioneers Altair, Amstrad, Kaypro, and Osborne.

Outside the DRI office at 801 Lighthouse Avenue in November 1980.
Photo: John Pierce
<https://computerhistory.org/wp-content/uploads/2024/04/
DRI-office-1980-861x1024.jpg>

In 1978, revenue topped $100,00 per month, and DRI purchased a
Victorian house at 801 Lighthouse Avenue for the company
headquarters. By 1980, DRI employed more than 20 people, and Fortune
magazine reported that the company generated revenue of $3.5 million,
five times the revenue of Microsoft at that time. Gary also acquired
a Piper aircraft that allowed him to fly from Monterey to meet
regularly with his customers in Silicon Valley and beyond.

To accommodate the expanding engineering staff hired to service the
hundreds of different computer models used by more than a million
people worldwide, DRI purchased a 1909 American Foursquare-style
residence at 734 Lighthouse. Today, it houses the offices of the
Carmel Pine Cone newspaper.

Gary in 734 Lighthouse Avenue. Photo: John Pierce
<https://computerhistory.org/wp-content/uploads/2024/04/
Gary-Kildall-Lighthouse-Ave.jpg>

One Friday afternoon, Gary called the engineering staff together and
announced that he would give them all a raise over the weekend. On
Monday, when they returned to work, contractors began raising the
building to make room in the basement for a new Digital Equipment
Corporation VAX 11/750 computer system. After several weeks,
supported by heavy wooden beams and house jacks, the engineers' desks
were five feet higher.

By 1983, DRI's annual sales reached $45 million. The company employed
over 500 people, including more than 100 engineers, and had expanded
into another building at 160 Central Avenue, which today houses the
Monterey Bay Aquarium's offices.

The IBM PC Effect
=================
In 1980, IBM established a new business division in Boca Raton,
Florida, to develop a desktop computer for the mass market. To get
the IBM PC, as it became known, to market as quickly as possible,
they used commercially available components, including an Intel
microprocessor chip. Bill Gates knew Gary from early discussions
about merging their companies and setting up shop in Pacific Grove,
so when an IBM procurement team visited Microsoft to license the
BASIC interpreter program, he referred them to DRI for an operating
system.

Gary at Monterey Airport with his Piper Aerostar.
Photo: Tom Rolander
<https://computerhistory.org/wp-content/uploads/2024/04/
Gary-Kildall-Monterey-airport-1024x703.jpg>

On Tue, 23 Apr 2024 04:26:55 -0000 (UTC)
Ben Collver <bencollver@tilde.pink> wrote:

> Fifty Years of the Personal Computer Operating System
> =====================================================
> By David Laws, April 18, 2024
>
[]

> Gary Kildall died in 1996 at age 52 following an accident in

Eh?
Wikipedia says:
Gary Arlen Kildall (/ˈkɪldˌɔːl/; May 19, 1942 – July 11, 1994) w

[]
--
Bah, and indeed Humbug.