[ale] linux and apples

[aaron]

On Tuesday 23 September 2003 13:17, Jonathan Rickman wrote:
> On Tuesday 23 September 2003 11:26, aaron wrote:
> 
> > Apple supported Open Source Xwindows layer working, too. OSeX is
> > FreeBSD at heart, so the boxes are extremely stable, reliable and
> > secure.
> 
> The misconception that OS X is FreeBSD with a pretty face is so widespread 
> that it's probably pointless for me to dispute it, but here goes...
> 
> OS X does not use the FreeBSD kernel. The kernel architecture of Mach is 
> drastically different and some would argue that it's better. It is no 
> more related to FreeBSD than Slackware. The userspace tools are "Unixy" 
> (in a cygwin kinda way) to be sure, but FreeBSD at heart it ain't. I 
> agree with all your other points.
>
> Jonathan Rickman

Thanks! Directed me to a little more research to make sure I wasn't totally 
awol on the FreeBSD aspects one finds in OSeX.

As apple describes it, the OSeX kernel as a whole consists of 3 integrated 
kernel layers using Mach, FreeBSD and an independent I/O component:

http://developer.apple.com/documentation/Darwin/Conceptual/
KernelProgramming/Architecture/chapter_3_section_3.html

=====================
"Above the Mach layer, the BSD layer provides OS personality APIs and 
services. The BSD layer is based on the BSD kernel, primarily FreeBSD. The 
BSD component provides:

file systems
networking (except for the hardware device level)
UNIX security model
syscall support
the BSD process model, including process IDs and signals
FreeBSD kernel APIs
many of the POSIX APIs
kernel support for pthreads (POSIX threads)

The BSD component is described in more detail in the chapter [BSD Overview].

===============================

I think OSeX may feel like BSD because there is, in fact, a whole level of 
FreeBSD kernel inside it that handles most user, file system and network 
level interactions. Describing the OSeX system as entirely FreeBSD is not the 
complete story, but as a user it's hard to see much -besides- the integral 
BSD kernel.

I think the I/O Kit helps explain OSeX's media power. An historic side line 
here is that the independent "I/O Kit" layer is reminiscent of the way the 
Amiga kernel managed a multi-microprocessor / shared memory space framework 
allowing many primary I/O operations of display, sound, keyboard, mouse, 
sprites, parallel, serial, et al to be handled with minimal CPU involvement. 
Most of why the 1985 boxes could do full screen, 4,000 color video resolution 
animation on a 7mhz CPU. 

peace
aaron