Computer Memory: 640K Ought to be Enough for Anyone

Bill Gates? James E. Fawcette? Nancy Andrews? Jerry Pournelle? InfoWorld? Apocryphal?

Dear Quote Investigator: Bill Gates is the one of the richest men in the world, but that does not mean that he correctly foresaw the future. In the early days of the personal computer industry Gates supposedly said the following about the IBM PC:

 640K ought to be enough for anyone.

The term 640K refers to 640 kilobytes of computer memory. But these days a computer often has a capacious memory that is tens of thousands of times larger, and this size continues to grow. The 640K limitation was once a real headache for programmers and users. This quote is notorious among computer enthusiasts and is typically dated to 1981, but Bill Gates has denied that he ever said it. Could you try to trace it?

Quote Investigator: During the 1990s Bill Gates wrote a syndicated newspaper column in which he answered questions from the public. When he was asked about the saying in 1996 he replied [BGLA]:

I’ve said some stupid things and some wrong things, but not that. No one involved in computers would ever say that a certain amount of memory is enough for all time.

The need for memory increases as computers get more potent and software gets more powerful. In fact, every couple of years the amount of memory address space needed to run whatever software is mainstream at the time just about doubles. This is well-known.

However, the computer periodical InfoWorld did attribute several statements to Gates that expressed acceptance or satisfaction regarding the 640K computer memory limitation. Top quotation expert Fred Shapiro, editor of the Yale Book of Quotations, located the earliest version of this sentiment credited to Gates [BGNN]:

When we set the upper limit of PC-DOS at 640K, we thought nobody would ever need that much memory.  — William Gates, chairman of Microsoft

These words appeared at the beginning of an editorial written by James E. Fawcette published in the April 29, 1985 issue of InfoWorld. But no precise reference was given, and the words did not occur as part of an interview.

QI has located the earliest instance of a close match to the saying specified by the questioner. This is the version that is often attributed to Gates today. It appeared in InfoWorld magazine in January 1990 in an article that presented a timeline for the development of the PC industry in the 1980s. The remark ascribed to Gates was placed in quotation marks [BGSF]:

IBM introduces the PC and, with Microsoft, releases DOS (“640K ought to be enough for anyone” — Bill Gates)

Here are additional selected citations in chronological order.

The earliest citation in this presentation is the one given above that is dated April 29, 1985. That cite ascribed to Bill Gates the belief that “nobody would ever need” 640K of computer memory [BGNN].

An insight into the mindset of many in the 1980s is displayed in a passage from a 1986 book. The author, Nancy Andrews, who was knowledgeable about computers, discussed her own belief that even 128 kilobytes of memory was “all the memory we’d ever need.” Yet, the author quickly recognized that more computer memory was needed to accomplish tasks of increasing sophistication [WGNA]:

When the IBM PC-1 was introduced in 1981, it came equipped with 64K of memory. Those of us who upgraded our systems to 128K thought we had all the memory we’d ever need. At first, there were very few programs available that needed as much as 128K. But as more and more software became available, the complexity of the programs increased and so did their memory requirements.

In July 1987 a similar sentiment was expressed by the computer columnist and prominent science fiction author Jerry Pournelle in an article titled “Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full” in the pages of InfoWorld [JPEN]:

My first microcomputer had 12K of memory. When I expanded to a full 64K, I thought I had all the memory I’d ever need. Hah. I know better now.

For a while it was just an annoyance, but the memory-resident software situation is now getting completely out of hand.

In February 1988 the computer columnist Steve Gibson ascribed the belief that 640K was enough memory to the designers of the IBM PC as a group. The term Visicalc used below referred to a popular spreadsheet application [SGEN]:

Unhappily, the original designers of the IBM PC felt that 640K of RAM would be more than anyone would ever need. After all, Visicalc operated usefully on a mere 48K Apple II!

In November 1988 another computer columnist working for InfoWorld, George Morrow, commented about memory limitations. He attributed a version of the opinion under investigation to Bill Gates. Morrow did not give a specific reference, and the words were not placed inside quotation marks. This important citation was located by Fred Shapiro [GMBG]:

Microsoft Corp. chairman Bill Gates once said 640K of memory was more than anyone needed. He was wrong.

In 1989 Bill Gates delivered a recorded speech to the Computer Science Club at the University of Waterloo about microcomputers. He presented his recollections concerning the size of memory [UWBG]:

I have to say that in 1981, making those decisions, I felt like I was providing enough freedom for 10 years. That is, a move from 64k to 640k felt like something that would last a great deal of time. Well, it didn’t – it took about only 6 years before people started to see that as a real problem.

In January 1990 InfoWorld attributed to Bill Gates a version of the quotation that is now commonplace on the internet and in the mass media. The words are inside quotation marks, but the periodical does not provide a precise reference, so it is not clear when Gates was supposed to have made the remark [BGSF]:

IBM introduces the PC and, with Microsoft, releases DOS (“640K ought to be enough for anyone” — Bill Gates)

In November 1995 the Washington Post published an article that contained a collection of quotations labeled “If They Only Knew.” The sayings were selected so that the speakers appeared to be foolish or wrong-headed. Below are three examples. Note that the date of 1981 was assigned to the words attributed to Gates. This date is often paired with the remark now [BGWP]:

“Computers in the future may weigh no more than 1.5 tons.”
— Popular Mechanics, forecasting the relentless march of science, 1949

“We don’t like their sound, and guitar music is on the way out.”
— Decca Recording Co. rejecting the Beatles, 1962.

“640K ought to be enough for anybody.”
— Bill Gates, 1981

In 1996 Gates denied that he made the remark as discussed earlier in this post. He also questioned the existence of any solid reference for the statement [BGLA]:

Meanwhile, I keep bumping into that silly quotation attributed to me that says 640K of memory is enough. There’s never a citation; the quotation just floats like a rumor, repeated again and again.

The words credited to Gates were given further circulation by the book “The Experts Speak: The Definitive Compendium of Authoritative Misinformation” where it appeared with a footnote justification. However, the footnote simply pointed to the 1995 Washington Post article mentioned above [BGES]:

“640K ought to be enough for anybody.”
– Remark attributed to Bill Gates (Founder and CEO of Microsoft), 1981

In conclusion, the evidence is mixed. The first known citation occurred in 1985 despite the claim that the comment was made in 1981. Indeed, there does not appear to be any direct support for the 1981 date beyond the fact that the IBM PC was introduced in that year. It is not clear when or where Gates made the statement given in the 1985 cite. Perhaps James E. Fawcette knows more about the circumstances. The 1985 and 1990 remarks appeared in quotation marks, but they were not part of interviews.

On the other hand, the comments by Nancy Andrews and Jerry Pournelle showed that a common mindset of the period was compatible with informal hyperbolic remarks of this type. The 1989 speech by Gates presented a more sophisticated analysis of the growth of computing power and memory.

Since Gates has denied the quotation and the evidence is not compelling I would not attribute it to him at this time. Thanks for this difficult interesting question.

[BGLA] 1996 January 22, Daily News of Los Angeles, “Computer Industry Offers Wealth of Career Options” by Bill Gates, Section Business, Page B1, Los Angeles, California. (NewsBank)

[BGNN] 1985 April 29, InfoWorld, “Give Me power” by James E. Fawcette, Page 5, Volume 7, Number 17, InfoWorld Publications, Inc., Menlo Park, California. (Google Books full view) link

[BGSF] 1990 January 1, InfoWorld, “The Wonder Years: How the PC Industry Grew Up in the ’80s”, Page 4, Volume 12, Number 1, InfoWorld Publications, Inc., Menlo Park, California. (Google Books full view) link

[WGNA] 1986, Windows: The Official Guide to Microsoft’s Operating Environment by Nancy Andrews, Page 268, Microsoft Press, Redmond, Washington. (Verified on paper)

[JPEN] 1987 July 27, InfoWorld, A User’s View: Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full by Jerry Pournelle, Page 46, Volume 9, Number 30, InfoWorld Publications, Inc., Menlo Park, California. (Google Books full view) link

[SGEN] 1988 February 22, InfoWorld, Tech Talk by Steve Gibson, Page 34, Volume 10, Number 8, InfoWorld Publications, Inc., Menlo Park, California. (Google Books full view) link

[GMBG] 1988 November 14, InfoWorld, Bus Wars by George Morrow, Start Page 59, Quote Page 60, Volume 10, Number 46, Column 3, InfoWorld Publications, Inc., Menlo Park, California. (Google Books full view) link

[UWBG] Audio file of speech delivered by Bill Gates in 1989 to the Computer Science Club at the University of Waterloo, Exact date not specified, Quote occurs around 22 minutes 25 seconds. (Accessed at on 2011 September 8; this cite is from WikiQuote) link

[BGWP] 1995 November 16, Washington Post, Cybersurfing: If They Only Knew by Evan Roth, Section Style, Page D7, Washington, D.C. (NewsBank)

[BGES] 1998, The Experts Speak (Expanded and Updated Edition) by Christopher Cerf and Victor S. Navasky, Page 231, Villard Books, New York. (Verified on paper)

One reply on “Computer Memory: 640K Ought to be Enough for Anyone”

  1. Excellent digging. You’re almost answering two questions: Did he say it? Where did 640K come from?

    The original IBM PC CPU could only address 1MB of RAM. Addressing was done in 64K segments. Some portion of that address space had to be reserved for peripheral boards, etc. The IBM PC designers, probably along with Gates providing input (as many books have documented), had to decide how to split up the 1MB. How much space reserved for peripheral boards, and how much for software. They decided that 384K was sufficient for hardware boards, and 640K would be enough for software.

    In sum, the 640K limit was simply a matter of where best to draw a line that had to be drawn inside a 1MB limitation that already existed by virtue of the Intel CPU architecture they had selected. The 640K decision was never intended to be ‘forever,’ but simply looking at the realistic lifetime of the original IBM PC platform. Due to the need for backward compatibility, the limit lingered for a very long time.

    Hope this may be of use.

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