Web Performance Matters

Previous posts in this series described the influence of Moore's Law and Wirth's Law on application performance, how to balance hardware capacity and software demand with a systematic approach to performance tuning, and the five fundamental elements of computer system performance.

This post is the second of a small group devoted to the importance of measurements. Kelvin's dictum ("if you cannot measure, then your knowledge is meagre and unsatisfactory"), and the popular saying, "you can't manage what you can't (or don't) measure," each advance the idea that measurements are indispensable. But such a sweeping claim may not actually be true in every instance, so I am now highlighting some slightly more focused statements about the value of measurements.

One accurate measurement ...

... is worth a thousand expert opinions! This witty saying by Grace Murray Hopper could be faulted by the overly literal as an idea that may not always be true. But its force springs from its amusing use of contrast. And having spent my entire career dealing with technical concerns, I can certainly appreciate why she said it, and visualize its potential for skewering colleagues whose opinions were not well supported by data. She served as a Rear Admiral in the U.S. Navy, so a military version of the Dilbert cartoon comes readily to mind. For those mental images alone, it is well worth remembering!

Naturally, it is especially memorable because it is clearly intended to be recognized as a clever parallel to the proverb, "a picture is worth a thousand words" (which itself is of surprisingly recent origin). There is really not a lot more to be said about the saying itself -- but it is an example of Grace Hopper's intellect, and it gives me a good excuse to revisit some of her other contributions to our history.

A pioneer of computing

Grace Hopper has been widely recognized as a true pioneer of computing. In 1969, she was awarded the first ever Computer Science Man-of-the-Year Award from the Data Processing Management Association. In 1973, she became the first person from the United States and the first woman of any nationality to be made a Distinguished Fellow of the British Computer Society.

In 1987, she was the first to be honored as a Fellow of the Computer History Museum. According to the Museum, she is ...

... in Charlene Billings's phrase, "the grandmother of the computer age." Her friends called her "Amazing Grace." She was a seminal influence on modern computing, developing software for the Mark I and the UNIVAC I computers, and leading the development of compilers for the COBOL language... The list of her awards and degrees exceeds two full pages, including the National Medal of Technology and thirty-seven honorary doctoral degrees.

Today's highlighted quotation is not the only memorable saying by Grace Hopper, whose words have been collected online at Yale.edu, Wikiquote, and About.com. I particularly enjoyed these:

On systems

• Life was simple before World War II. After that, we had systems.
• In pioneer days they used oxen for heavy pulling, and when one ox couldn't budge a log, they didn't try to grow a larger ox. We shouldn't be trying for bigger computers, but for more systems of computers.

On innovation

• The most dangerous phrase in the language is, "We've always done it this way."
• A ship in port is safe; but that is not what ships are built for. Sail out to sea and do new things.

On information

• We're flooding people with information. We need to feed it through a processor. A human must turn information into intelligence or knowledge. We've tended to forget that no computer will ever ask a new question.
• Some day, on the corporate balance sheet, there will be an entry which reads, "Information"; for in most cases, the information is more valuable than the hardware which processes it.

On office politics

• At any given moment, there is always a line representing what your boss will believe. If you step over it, you will not get your budget. Go as close to that line as you can.
• It's easier to ask forgiveness than it is to get permission.

Documenting the computer bug

Grace Hopper did not invent the term "bug" for a program flaw, but she is remembered for her action in recording a particular bug at Harvard University on September 9, 1947. A moth flew into a Harvard Mark II Relay Calculator that was being tested, causing the machine to malfunction. Grace Hopper recorded the event, together with the offending bug, in the machine's logbook, adding the comment "First actual case of bug being found".

The operators put out the word that they had "debugged" the machine, introducing the term "debugging a computer." The logbook containing that page is now preserved in the National Museum of American History at the Smithsonian in Washington DC.

This post is the fifth in a new series on fundamental truths about performance.
Tags: performance, measurement, management, expert opinion, Grace Hopper, software bug, debugging, performance wisdom