HFS+

Linus Torvlads [smh.com.au]

When asked about which is better Windows or Mac OS:

• I don't think they're equally flawed. I think Leopard is a much better system. On the other hand, (I've found) OS X in some ways is actually worse than Windows to program for. Their file system is complete and utter crap, which is scary. I think OS X is nicer than Windows in many ways, but neither can hold a candle to my own (Linux). It's a race to second place.

HFS+

•File system developed by Apple•Used since OSX 8.1 (January 19, 1998)•Used by computers running OSX, iPods

HFS+

•Block addresses are 32-bit length•uses Unicode, permits filenames up to

255 UTF-16 characters in length•Uses B*-trees to store most volume

metadata•Maximum file size is 2^63 bytes

HFS+

•Journaling support added November 11, 2002 (known internally as HFSJ)

•With 10.4, Apple added support for Inline Attribute Data records allowing support for access control list-based file security (compatible with Win XP, 2003)

HFS+

How does OSX FS store extended attributes for the files?•Any regular file may have a list of

extended attributes•Extended attributes are limited to that

which can fit within a single B-Tree•Denoted by a name and the associated

data•The name is a Unicode string

How does OSX FS store extended attributes for the files?•Say you have a file with comment. If you

move that file to a thumb drive or CDROM (which does not support extended attributes), is the comment lost?

How does OSX FS store extended attributes for the files?•File is given attributes•File is then copied to a lesser volume

(Fat32)•A file starting with a “.” is created and

added to the file system•Files starting with “.” are hidden in the

Unix world but show up in Windows

Resources:

• http://developer.apple.com/technotes/tn/tn1150.html

• http://www.smh.com.au/news/technology/q-and-a-with-linus-torvalds/2008/02/05/1202090403120.html?page=fullpage#contentSwap2

• http://arstechnica.com/reviews/os/macosx-10-4.ars/7

Demo