Architosh Staff (info@architosh.com)

28 Mar 2001

Mac OS X: Core Technologies Overview -2

Continued from:

In this series will be be detailing Mac OS X from a "system overview" perspective. Many readers have never had the chance to fully delve into Mac OS X's technical background beyond the material posted at Apple.com.

BSD and the Unix Story

Integrated into the Mach layer of Mac OS X is a custom version of the BSD operating system, a UNIX OS that came from Berkeley University way back in the late 70's. Today BSD exist in more than a couple versions, including FreeBSD and OpenBSD.

Key to Mac OS X's use of the BSD operating system is the file systems and networking facilities. In addition, there are the BSD API sets and the POSIX threading support layer.

BSD is a leading OS for web servers worldwide, running some of the worlds largest and busiest Web sites, including THE largest one of all, Yahoo. To see Netcraft web server info on Yahoo and other BSD OS driven web sites click here.

BSD UNIX is just one component of Mac OS X's UNIX lineage, of which there is an excellent UNIX family tree available in which you can see how Mac OS X came to be.

OS X's Family Tree (On the UNIX Side)

Clearly Mac OS X has a non-UNIX side of the family which we all know and love. But this non-UNIX blood will continue to diminish over time as we move forward with Mac OS X.

So who are Mac OS X's blood relatives today?

Mac OS X can be seen as the child of two UNIX parents: BSD UNIX and NeXTSTEP, which in turn has a bloodline back to BSD. In fact, Mach, IRIX and Sun's SOLARIS all have bloodlines back to BSD UNIX (according to the UNIX family tree). Mac OS X is most related to these Unixes today.

Mac OS X's UNIX Command Line

Mac OS X has a real UNIX command line for those UNIX users and Mac power users who are really ambitious! (see below).

What you see above is the Terminal application (command line) in black sitting on top of the ProcessViewer application window. You can kill an application through the ProcessViewer window by quitting the process and you can see stats on a process, including the 'virtual memory size' and the 'resident physical memory' size currently implemented.

FYI, the Finder in Mac OS X has a virtual memory size of approximately 70,192 Kbytes while it has only a 20,435 Kbytes resident memory size when sitting idle. Upon launching IE 5.5 for OS X the resident memory (physical) will bump up a bit by a megabyte or two.

Next: Overview - 3