jonr - Slashdot User

Submission + - Null References: The Billion Dollar Mistake (qconlondon.com)

Submitted by

jonr

on Tuesday March 03, 2009 @10:13AM

jonr writes: "I call it my billion-dollar mistake. It was the invention of the null reference in 1965. At that time, I was designing the first comprehensive type system for references in an object oriented language (ALGOL W). My goal was to ensure that all use of references should be absolutely safe, with checking performed automatically by the compiler. But I couldn't resist the temptation to put in a null reference, simply because it was so easy to implement. This has led to innumerable errors, vulnerabilities, and system crashes, which have probably caused a billion dollars of pain and damage in the last forty years. In recent years, a number of program analysers like PREfix and PREfast in Microsoft have been used to check references, and give warnings if there is a risk they may be non-null. More recent programming languages like Spec# have introduced declarations for non-null references. This is the solution, which I rejected in 1965.

This is an abstract from Tony Hoare Presentation on QCon. I'm raised on C-style programming languages, and have always used null pointers/references, but I am having trouble of groking null-reference free language. Is there a good reading out there that explains this?"

Submission + - Phantom OS, the 21st Century OS?

Submitted by jonr on Friday February 06, 2009 @02:11PM

jonr writes: Phantom doesn't have files. Well, there are no files in the sense that a developer opens a file handle, writes to it, and closes the file handle. From the user's perspective, things still look familiar — a desktop, directories, and file icons. But a file in Phantom is simply an object whose state is persisted. You don't have to explicitly open it. As long as your program has some kind of reference to that object, all you need to do is call methods on it, and the data is there as you would expect.

This is what has been bugging me for years. Why, in the year 2009, after 50 years of OS development, are we still opening and closing files manually? Why don't we just edit data in memory and let the OS handle the physical storage?
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Submission + - Sony camera with Linux? (linuxpromagazine.com)

Submitted by

jonr

on Tuesday January 13, 2009 @08:18AM

jonr writes: "At the Las Vegas Consumer Electronics Show Sony presented the new camera from its Cyber-shot product line. The DSC-G3 comes with a Zeiss lens with 4x zoom, a large 3.5" touch display and 4 GBytes of internal memory. Most interesting is the camera's software that includes, among other things, face and scene recognition, based on Busybox and Kernel 2.6.11 for the Access Linux Platform (ALP)."

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