An Answer To "What is Mac OS X?"

XCube writes: "'What is Mac OS X?' is a fascinating article over at KernelThread.com. According to Amit Singh it's a hacker-over-friendly answer to that question and a low-level taste of Apple's OS. The extensive article covers many details on Mac OS X: history, Mac firmware & boot loader, system architecture, kernel, startup, file systems, app environments, programming facilities, available software, and more. A great read if you are interested in Mac OS X, though some stuff is too technical methinks. On second thought, this may be a better read if you're *not* interested in Mac OS X! The author says he wrote it to introduce Mac OS X to the Linux User's Group at his work."

Comments

Carbon's roots are older

[saddino]

Carbon. This is a set of procedural C-based APIs for Mac OS X that are based on the old Mac OS 9 API (actually dating back as far back as Mac OS 8.1)

To nitpick: actually, a lot of the Carbon APIs go as far back as System 1.0 -- most of QuickDraw for example.

Re:Carbon's roots are older

[frankie]

The article is conflating two different things - either an accidental mis-edit or an intentional oversimplification.

Carbon is based on the classic Mac APIs which go way back to 1984, while the Carbon API actually exists (and is available for calls) in MacOS 8.1 and higher via the CarbonLib classic extension.

Re:Carbon's roots are older

[gwernol]

Carbon is based on the classic Mac APIs which go way back to 1984, while the Carbon API actually exists (and is available for calls) in MacOS 8.1 and higher via the CarbonLib classic extension.

Actually (if you care about all the historical details of Mac OS X's evolution) Carbon was originally based on the QuickTime library, which in turn was based on the classic Mac APIs. I was an engineer on the QuickTime team during the early Rhapsody days up through Mac OS X beta.

When Rhapsody (basically the NextStep OS) was being developed it quickly became obvious we needed to support classic Macintosh applications. QuickTime had already been ported to an early Rhapsody version, and it just so happened QuickTime already carried around an API that contained about 70% of the Mac OS functionality. This is how QuickTime runs on Windows and why porting Carbon/classic Mac apps to Windows is (relatively) painless if you know to call the QTW libraries. So Apple effectively had the start of Carbon on NextStep as a result of the QuickTime port. Rhapsody became Mac OS X, the QuickTime library support was spun out to its own team and became Carbon.

None of which really disagrees with your post, just a little more detail on the exact process.

The question

[CelticWhisper]

It's been at the back of your mind all along, always there, you're always asking...

"What is Mac OS X?"

Do you want me to show you, Neo...er...Steve? Eat the blue apple, and you'll go on living your life, believing whatever you want to believe. Eat the red apple, and I'll show you how deep the worm hole goes. And you'll realize that there is no Mac OS X. It's only your mind that has unfathomably sexy UI elements.

Potential Linux Switchers: Read Up

[Spencerian]

If you've been under a rock and haven't read much about OS X, still view Linux as a strong desktop OS, but hate having to fight to get the latest software, hardware, or other common computer accessories working without a call to your other Linux buddies, you should get a kick out of this article.

While the author disavows the article to a degree, it may be of great use to Linux and other UNIX users who haven't a clue of the true nature of OS X beneath its GUI interface. From the kernel, to a typical Mac's boot firmware, to its BSD origins, this is probably one of the better free web-accessible summaries that Linux geeks could appreciate.

OK, it might not make you switch, but note that this guy admits to using OS X for only 3 years or so, and he's gained quite an understanding of it.

Will OS X work for you best? YMMV.

Re:Potential Linux Switchers: Read Up

[drinkypoo]

I agree that open firmware is a thing of beauty. However we should eventually attain the same level of convenience with LinuxBIOS. (The problem right now is diminutive EEPROM/FLASH bios.) However on PCs you no longer have to worry about IRQs, DMA conflicts, or IO ranges, as long as you're not using legacy hardware. These days, some machines even have no ISA bus whatsoever - Even the legacy PS/2 keyboard and mouse are on PCI. Macs still have to deal with interrupts and such, they just don't bother you with it, and neither do modern PCs. I haven't had to deal with IRQs and shit since the last time I installed a non-pnp ISA card. Which was a long, LONG time ago.

Mac hardware hasn't been special since PCs went to the PCI bus and apple hardware stopped having the drivers in rom on the card. NuBus was a paragon of autoconfiguration equalled by no one but the Amiga. But now that drivers are in the software and not adapter ROM, that advantage is nonexistent.

It's also worth pointing out that until the G5, apple hardware has had poor bus architecture and slow memory buses. So while the designs are supposedly clean (I have a yosemite so I know that is a lie; I am also familiar with the IIfx, which didn't even follow Apple's standards, let alone anyone else's, and even needed a nonstandard SCSI terminator) they have usually been dated. The G5 is an exception; it sure would be nice if OSX were 64 bit though. Apple finally has the superbadass hardware, and their OS doesn't even take full advantage of it. By the time they have a 64 bit OSX, AMD's hammer chips will have come down further in price, and XP-64 will be running on them, and they'll squander their "lead" once more.

Re:OS X 10?

[mfago]

One word: Photoshop.
Bzzt...Gimp doesn't count so don't bother.

I agree that Gimp 1.x has a GUI designed by a masochist. Check out version 2 though -- much better IMHO.

Nevertheless, more commercial apps and a gorgeous desktop that is truly ready for grandma and grandpa, with BSD, X11, and GCC for junior. Other than being completely "free as in freedom," and games, what else could you want?

uh

[SweetAndSourJesus]

How much "hacking the code" have you done on Linux? Be honest. Have you ever needed to significantly modify your operating system's source code? Do you even know how?

Are you just bitching because it isn't Free for the sake of bitching?

interesting article...

[Anonymous Coward]

It's good to explain more of the underpinnings OS X. You see, NeXTSTEP was almost the perfect operating system and development environment.

The NS environment (living on in Aqua today) is just so cool. Well-designed interfaces abound. Design patterns everywhere, created when the term "Design Pattern" had barely been explored in the computer world. For instance: most objects use delegation to extend their behavior. Not subclassing! Just compare building a GUI in Swing to Cocoa, it's like salt and sugar.

Objective-C is a wonderful semi-dynamic language, much nicer than C++.

Programming the mac is a true joy, even if all this dynamic dispatch is a little slow and hardly anybody uses macs. :-)

Re:OS X on x86, I wish

[JudgeFurious]

Well, then I'm thinking your best bet is to go out and find yourself a used blue and white G3 (can be had very reasonably priced on ebay IF you take your time and don't rush it) and follow that with a CPU upgrade. They're coming down to a fairly comfortable price for those machines. Get that B&W going about 500Mhz and add Panther. Don't worry about the price of Panther (I figure if you're going to pirate XP then why pay for Panther?) and you got your firsthand look at OSX.

I pretty much did it that way and then decided I loved this shit enough to give them $3K to see it run on their new machines. I'm not the least bit disappointed either.

Everybody's different but as far as I'm concerned to hell with Windows and screw waiting on Linux to get it's collective desktop shit together. OSX beats both.

Re:Hey, Wait a second

[BorgCopyeditor]

You know what else pisses people off?

Sticking pins in them! Some people say it's wrong, but that's what makes it fun!!!

Re:though i love linux

[GlassHeart]

i consider it to be a best of both worlds

When a company does such a good job, then the intelligent consumer would pay the company so it can improve. Apple does not survive by your applause, but by your purchasing dollars. Even your dollars spent on Microsoft Office for the Mac is partially a powerful vote for Apple.

Point is, if all we are going to do is to sit around and dish out glowing reviews, then we should not be surprised when (not if) a company we so approve of fails. Put your money where your mouth is.

i regret lacking the funds to buy myself a peachy powermac g5 cuz i'm quite tempted by os x panther and the ilife bundle (man garageband look awesome!)

GarageBand requires a G4 with DVD drive for full operations. The entry-level eMac satisfies this at $800 brand new, or under $700 refurbished. The $800 price, if you wait a few weeks, would include the $50 iLife.

Don't get me wrong. $800 is still real money, and is still more expensive than a Dell box. However, it's not $1,800, which is what an entry-level G5 would cost, and the Dell box won't have GarageBand, its big brother Soundtrack, or Final Cut Express and big brother Final Cut Pro.

It's compiled! DAMMIT!!

[The Muffin Man]

Hmm, he lists Lisp amongst the interpreted languages. I hope the rest of the article is more accurate...

Edi.

== Programming Language Myths ==

BASIC Myth: People who learn BASIC go on to learn other languages.
Reality: Most people who learn BASIC go on to find less nerdy ways of writing "Mr. Gzabowski is a lame teacher" over and over again.

C Myth: C programs are insecure, full of buffer overflows and such.
Reality: C programs are only insecure if written by imperfect programmers. Since all C programmers know that they are perfect, there's no problem.

COBOL Myth: COBOL is dead.
Reality: It stalks from out the ancient vaults of death, its putrid mind drawn to the blood of the living.

Forth Myth: Forth makes no sense.
Reality: backwards. think to have just you sense, perfect makes Forth

Java Myth: You need Java to do business applications.
Reality: You need Java to get a job.

Lisp Myth: Lisp is an interpreted language.
Reality: Lisp is COMPILED DAMMIT COMPILED! IT'S IN THE FUCKING STANDARD!!!

Pascal Myth: Pascal is a toy.
Reality: Oh, wait, that is not a myth, it is true ...

Perl Myth: Perl is impossible to read.
Reality: You are not taking enough psychedelics.

Python Myth: Python's only problem is the whitespace thing.
Reality: Python's only problem is that it is fucking slow.