Smalltalk developer looks back over 40 years

Stephen Withers
Monday, 13 December 2010 11:32

IT People - People

A veteran developer has presented a highly personal retrospective covering the last 40 years, and urged his younger colleagues to have fun with their work.

Dan Ingalls' closing presentation was one of the highlights of the YOW! software developers conference held in Melbourne this month. He is probably best known for his work in developing Smalltalk at Xerox PARC in the 1970s.



'40 Years of Fun With Computers' was an overview of Ingalls' career, starting with the first program he ever wrote. Given the task of writing a FORTRAN program to print out successive powers of 2, he started with a conventional six-line program that calculated the first 31 - the limit being the maximum value of an integer variable.

He then worked out a way of doing almost infinite-precision arithmetic by using arrays, but the resulting program was 25 lines long, which was significantly longer than those being created by his classmates. Further effort got it down to 10 lines, but Ingalls still wasn't satisfied. When he realised there was a way of carrying out the task using ASCII codes instead of numeric values, he was able to reduce it to six lines including "an appropriate comment."

As a graduate student, he developed a program that could introduce additional statements into FORTRAN programs to gather statistics about which sections were executed the most. (This knowledge can be used to determine where optimisation efforts should be directed.) He dropped out to commercialise the program, but discovered that most of the big potential users were government funded and wanted their computers to be heavily loaded to help justify bigger budgets. A COBOL version was more successful.

One customer was working on speech recognition at Xerox, and subsequently hired Ingalls as a consultant. Ingalls worked across the corridor from Smalltalk creator Alan Kay, "and that's how I got into Smalltalk."

One of Ingalls' major contributions was the invention of the BitBlt operation for graphics. Please read on.