This week I learned...

• To view the wiki-source of any MediaWiki page, add ?action=raw to the URL. (Good for scripting.)

• Unix has system calls like mlock, mincore, mprotect, and madvise that interact with the virtual memory manager. (Some are more standard than others.) I only knew about the venerable mmap.

• There's a fast, easy way to avoid the agonizing worst-case fragmentation you can get when you use a simple size-class/freelist implementation of malloc: per-page freelists.

• You can implement a copying collector in 100 lines of easy-to-read C that won't blow the stack!

• The Encyclopædia Brittanica is about 33,000 pages long, and I'm not the only one to raise an eyebrow at the volume titled “Menage - Ottowa”.

I also keep learning about good decisions the JVM designers made, but they're even less exciting than the above.