The Old New Thing

Psychic debugging: Why your expensive four-processor machine is ignoring three of its processors

March 21, 2005 Mar 21, 2005 03/21/05

Raymond Chen

On one of our internal mailing lists, someone was wondering why their expensive four-processor computer appeared to be using only one of its processors. From Task Manager's performance tab, the chart showed that the first processor was doing all the work and the other three processors were sitting idle. Using Task Manager to set each process's...

Windows NT Security in Theory and Practice

March 16, 2005 Mar 16, 2005 03/16/05

Raymond Chen

Today, I'm not writing anything new. Instead, I'm referring you to the series of articles by Ruediger Asche starting with Windows NT Security in Theory and Practice. These articles are quite old but the principles are still sound. Just bear in mind that the newer stuff won't be covered...

A subtlety in restoring previous window position

March 14, 2005 Mar 14, 2005 03/14/05

Raymond Chen

A common feature for many applications is to record their screen location when they shut down and reopen at that location when relaunched. If implemented naively, a program merely restores from its previous position unconditionally. You run into usability problems with this naive implementation. If a user runs two copies of your program, the ...

Performance gains at the cost of other components

March 11, 2005 Mar 11, 2005 03/11/05

Raymond Chen

In the operating systems group, we have to take a holistic view of performance. The goal is to get the entire system running faster, balancing applications against each other for the greater good. Applications, on the other hand, tend to have a selfish view of performance: "I will do everything possible to make myself run faster. The impact ...

Keep your eye on the code page

March 8, 2005 Mar 8, 2005 03/8/05

Raymond Chen

Remember that there are typically two 8-bit code pages active, the so-called "ANSI" code page and the so-called "OEM" code page. GUI programs usually use the ANSI code page for 8-bit files (though utf-8 is becoming more popular lately), whereas console programs usually use the OEM code page. This means, for example, when you open an 8-bit ...

Windowless controls are not magic

February 11, 2005 Feb 11, 2005 02/11/05

Raymond Chen

It seems that when people notice that the Internet Explorer rendering engine doesn't use HWNDs for screen elements, they think that Internet Explorer is somehow "cheating" and doing something "undocumented" and has an "unfair advantage". Nevermind that windowless controls have been around since 1996. They aren't magic. Mind you, they're a ...

The strangest way of rounding down to the nearest quarter

January 26, 2005 Jan 26, 2005 01/26/05

Raymond Chen

In a previous life, I wrote database software. A customer complained that one of their reports was taking an unacceptably long amount of time to generate, and I was asked to take a look at it even though it wasn't my account. The report was a vacation-days report, listing the number of vacation days taken and available for each employee. ...

Bringing cryptic command lines to Windows

January 24, 2005 Jan 24, 2005 01/24/05

Raymond Chen

The CMD.EXE batch language can be awfully cryptic, but for those who miss the richness of command lines like or bursts of line noise masquerading as a pipeline of "find", "sed", and "awk" processes, Microsoft Windows Services for Unix is available for free download...

Hyperlinking to Hutchison Whampoa Limited forbidden

January 20, 2005 Jan 20, 2005 01/20/05

Raymond Chen

Maybe they don't want people to find them. The copyright notice for the web site of Hutchison Whampoa Limited states, Copyright Hutchison Whampoa Limited. 2003. All rights reserved. No person, whether an individual or a body corporate, shall create or establish a hyperlink to the HWL Corporate Website by hypertext reference or imaging ...

Cleaner, more elegant, and harder to recognize

January 14, 2005 Jan 14, 2005 01/14/05

Raymond Chen

It appears that some people interpreted the title of one of my rants from many months ago, "Cleaner, more elegant, and wrong", to be a reference to exceptions in general. (See bibliography reference [35]; observe that the citer even changed the title of my article for me!) The title of the article was a reference to a specific code ...