We are doing our examination project on how to implement multi layer design on Mac OS X. And we have some things that we wounder about, maybe you can help us out? Or at least give us a point in the right direction.

* How much of Mac OS X source code is linux, and how muck is Apple's own code?
* Which parts of the operating system is it ok to alter or change if you're not employed by apple?
* Is it possible to alter Mac OS X settings with code that you have build your self, and can they affect the system programs? How is it with properties and writing rights?
* Is there a possibility that Apple could lend out it's user management? Or is there anyone who knows how to limit what a user i able to do?
* What is apple's opinion about multi layer design?
* How can I hide files for ordinary users? Is it possible to show programs fore some, and not for others?
* How can you do for new settings to take affect? Is it to logout and login again, or perhaps do you have to restart finder?

best
Rickard

[Gargoyle]

www.apple.com/macosx

None of Apple's OS is "Linux". Darwin (the stuff that does all the hard work under the slick GUI) is open source - Yes, as in Free! You can even download it yourself and install it on your PC!

Files and applications can be hidden from various users, and settings normally take effect the instant you change them! I think you have used windows for too long - If you go and buy yourself a Mac you will not only be a much happier computer user but you will also get a A+ on your project!

Oh, and there is a lot more detailed information at Apple's Developer Site

Enjoy

[Bryson]

It's not Linux...it's UNIX. Linux is a type of Unix, Darwin is a type of Unix.

See here.

[staph]

Linux and Darwin are only UNIX if the trade mark has become generic: see here and here. They are both broadly speaking posix compliant, though.

Not that I'm pedantic or anything. I'm pretty sure this is the subject of a live legal dispute between Apple and the Open Group atm, btw. It's been a bit quiet lately, maybe they've settled and I didn't notice. Apple obviously have their own view, although their wording seems somewhat ambiguous.

[Brad]

I think it would greatly denefit you to read What is Mac OS X? It's a very good article for the technically-minded folks.

How much of Mac OS X source code is linux, and how muck is Apple's own code?

As answered already, all of the kernel and much of the drivers are open source as Darwin. Darwin is a breed of FreeBSD, Mach, and Apple's own secret sauce.

Which parts of the operating system is it ok to alter or change if you're not employed by apple?

All of it? I'm not sure what this is supposed to mean.

Is it possible to alter Mac OS X settings with code that you have build your self, and can they affect the system programs? How is it with properties and writing rights?

Absolutely, yes. There's lots of software that does this. However, you may also have to write code that will interface with Apple's authentication framework so you can have permission to make changes that are not normally allowed. Again, this is not uncommon and is relatively easy and painless thanks to the classes Apple has provided with Cocoa. I wrote a program that had to authenticate about two years ago and, as I recall, the code to call up Apple's authentication stuff was literally a dozen lines long.

Is there a possibility that Apple could lend out it's user management? Or is there anyone who knows how to limit what a user i able to do?

I'm not sure what you mean by the first question, but for the latter there are LOTS of options. Mac OS X uses the standard owner/group/world read/write/execute metadata parameters that the rest of the Unix/Linux world uses. Tiger introduces new support for ACLs also. That's all just on a filesytem-level, though. In the user interface, check out the System Preferences panel Accounts. You can restrict the user like these pics:




Tiger, again, introduces many more options for limiting user abilities including a number of application-specific limitations. Here are a few shots:

What is apple's opinion about multi layer design?

I'm not sure what you mean by this. Would you please clarify what you define as multi-layer design?

How can I hide files for ordinary users? Is it possible to show programs fore some, and not for others?

See my answer to two questions ago. For the former, simply don't give them read access to a directory or file. For the latter, use the System Preferences controls.

How can you do for new settings to take affect? Is it to logout and login again, or perhaps do you have to restart finder?

Again, I don't follow. Most settings take effect immediately. The only things that require relaunching the Finder or logging out are those done by hackish third-party programs that aren't natively toggled.