Talk:XNU

message: Two things:
* I think it is important to mention Mac OS X as a lot more people use it than Darwin, and a lot more people will recognise the OSX name than the Darwin name.
* If we are going to be specific that XNU code is from the FreeBSD kernel not the FreeBSD operating system, then we should then be specific that XNU code is from the Mach kernel not the Mach operating system. AlistairMcMillan 22:34, 24 Sep 2004 (UTC)
replies: text: Is Mach an operating system? – Mipadi 03:24, 18 December 2005 (UTC)
replies: text:  Mach is only a kernel, to be specific, it is a microkernel, most important part of the operating system. XNU is the operating system what use Mach microkernel. Darwin is the development platform what combines XNU operating system and compile tools and settings. Mac OS X is the software system what includes Darwin and other Mac OS X technologies. The XNU is not kernel. It is the complete operating system what includes some FreeBSD operating system parts to offer filesystem and network stack. The FreeBSD is monolithic kernel == operating system. Monolithic kernels are alone operating systems. Microkernels are not operating systems but parts of it. The operating systems were first monolithic kernels. Then later OS designers got idea to improve the security and stableness of the operating systems by slicing them to parts. To a small microkernel and then OS servers (modules) what were running as supervisor mode together with the microkernel. Together the microkernel + OS servers build up the operating system as the  monolithic kernel was alone. The XNU is marketed as "hybrid kernel" what is actually microkerne-based operating system but just OS servers located little different way, but still separated from the kernel itself. I must admit that this is very difficult topic to many. Because marketing from big companies and even from GNU hides the truth behind own purposes of fame. 62.165.184.109 (talk) 20:37, 30 August 2009 (UTC)

text: I think Alistair is right that MacOS should be mentioned a lot more. In particular, there should be a summary of what MacOS provides that XNU does not in order to make a complete operating system. Also, the page states that XNU is "open source", which implies I could compile a custom kernel for MacOS. Is that correct or does Apple use key signing to prevent it? How much freedom does the kernel being open source actually give MacOS users? Ben (talk) 22:09, 19 March 2021 (UTC)
thread_title:  Two things 

message: Mac OS X was originally populated with mostly NetBSD userland.  It wasn't heavily moved to FreeBSD until later (I suspect once Jordan Hubbard was brought into Apple from the FreeBSD project). —The preceding unsigned comment was added by 68.158.68.247 (talk • contribs).
Seconded.  Wilfredo Sanchez was a NetBSD developer for a while synching the userland trees between Darwin and NetBSD.  NetBSD's portability made it easier for Apple to get a current userland (instead of the crufty NeXT/Rhapsody one).  The move to FreeBSD was only AFTER Jordan was on-board at Apple and was in a management position. Because of the incestuous nature of BSDs, the differences in userlands are generally innocuous. 71.12.163.234 (talk) 11:46, 28 October 2010 (UTC)
thread_title:  Darwin userland 

message: The article now states: "Currently, XNU runs on x86 (Intel and AMD) and PowerPC based processors...".  Didn't Apple also have to port XNU to the ARM architecture, in order to get a trimmed down OS X to run on the iPhone (which appears to be ARM-based)?  --Georgeryp 03:54, 7 September 2007 (UTC)
replies: text: Yes, and it now runs on ARM64-based Macs.  I've updated that to indicate that it currently supports ARM64 and x86-64, and to indicate when 32-bit x86 and 32-bit ARM support were dropped (and to use the  template). Guy Harris (talk) 20:58, 5 February 2021 (UTC)
thread_title:  ARM processor too? 

message: i appreciate the limited mention of user space drivers, but would appreciate a bit more info.  kernel space drivers are mentioned, as is the possibility of writing user space drivers, but no actual user space drivers are mentioned.  are there any?  are there likely to be any?  
this is supposedly an architectural advantage, so whether it actually pays off in practice is significant.  —Preceding unsigned comment added by 69.253.239.161 (talk) 17:59, 15 May 2008 (UTC)
thread_title:  more on userspace drivers? 

message: some discussion of performance compared with other operating systems as well as how well xnu scales when deployed on multiple cores or processors would be welcome.  —Preceding unsigned comment added by 69.253.239.161 (talk) 19:34, 15 May 2008 (UTC)
thread_title:  performance and scalability? 

message: Which is correct?  Zee-New or X-N-U? --76.100.200.168 (talk) 03:03, 25 July 2008 (UTC)
replies: text: Great. Now we can argue over whether it's "officially" pronounced ten-en-you. :) MFNickster (talk) 02:05, 29 March 2009 (UTC)
replies: text:  official pronunciation is snoo  — Preceding unsigned comment added by OMPIRE (talk • contribs) 20:01, 7 May 2014 (UTC)
replies: text:  [citation needed] Guy Harris (talk) 20:51, 7 May 2014 (UTC)
replies: text:  [forum link] http://forums.macnn.com/90/mac-os-x/135639/10-3-darwin-freebsd-5-0-a/
It's meant to be part of a joke, as in "what's XNU?"  — Preceding unsigned comment added by OMPIRE (talk • contribs) 20:55, 7 May 2014 (UTC)
thread_title:  Pronunciation 

message: Mach message passing is pretty well documented elsewhere but how it works in XNU seems a bit mysterious.  How much of the Mach Microkernel's communication protocol is maintained?  —Preceding unsigned comment added by 69.136.108.216 (talk) 17:04, 2 March 2009 (UTC)
thread_title:  Message passing within the kernel? 

message: Does the kernel contain any AT&T/Novell or CMU copyrighted code.  If so, was a license purchased outright?  If not, when was it purged? -- Beland (talk) 15:29, 6 March 2009 (UTC)
replies: text: I refer the honourable gentleman, to my previous answer. AlistairMcMillan (talk) 19:15, 6 March 2009 (UTC)
thread_title:  Licensing 

message: Over and above the issues brought up in the comment for the edit removing the "Reception" section, the article that section cited isn't really a very good review - it's a speculative comment about what the author thought was one particular aspect of XNU.  And, while he was criticizing Mach for "[putting] anything that accesses hardware into the microkernel", he was also criticizing microkernels for all the context switches between user processes that they require.  XNU not only puts network and storage drivers in the kernel, it also puts the stuff that calls the network and storage drivers - file systems and networking stacks up to the transport layer - into the kernel.  That's why it's sometimes labeled a hybrid kernel, although a certain other Linux fan considers "hybrid kernels" to just be marketing.
So I'd say the removal of that section, in the state it was in, was no loss. Guy Harris (talk) 18:34, 16 July 2015 (UTC)
thread_title:  "Reception" section