Understanding Mac OS X Kernel

An anonymous reader writes "Kernelthread.com has published a flash presentation overview of the Mac OS X kernel. Its title is 'A Tour of the Mac OS X Kernel' and it also covers Tiger features. Maybe interesting to note is that the slides are from a talk given to the NSA. Well, there is a nice security architecture diagram towards the end of the presentation."

amazing!

[by Anonymous Coward]

A flash presentation that didn't turn my p4 into a 386!

Re:amazing!

[brilinux (255400)]

What, did it turn it into a G5?

inside the kernel

[by Anonymous Coward]

Does it give away the kernel's secret recipe?

Re:inside the kernel

[commodoresloat (172735)]

Mmmm, kernel pancake....

Re:inside the kernel

[green pizza (159161)]

kernel's secret recipie
You don't need 11 herbs and spices, that's for sure. "Seasoned Oven Fried Chicken" spiced with cheap McCormick Season-All Seasoned Salt [mccormick.com] from your local grocery store will give you almost the same flavor. As an added bonus, you can control exactly how much or how little grease you want! Take that, KFC!

Eek, a presentation in flash!

[Psychic Burrito (611532)]

There is no way to step back (at least I found none), to get an overview, to jump to a certain frame (like the mentioned security architecture diagram) - why do people make presentations in flash, instead of pdf or css (example [andybudd.com])?

Keynote

[TimmyDee (713324)]

I'm willing to bet it's in Flash because he did the presentation in Keynote. While the SWF export in Keynote isn't great, at least it preserves transitions, fonts, and other formatting options and doesn't look like shit (like the HTML export of another presentation software).

Plus, it takes one step to export. I haven't seen anything that will do that with CSS.

I wish it was PDF

[green pizza (159161)]

I'm willing to bet it's in Flash because he did the presentation in Keynote.
Too bad he didn't export it to PDF. Keynote 2 (the version that ships in iWork 05) has an excellent PDF exporter.

Re:I wish it was PDF

[jeblucas (560748)]

Please read what OP said:

While the SWF export in Keynote isn't great, at least it preserves transitions, fonts, and other formatting options...

That's a fancy PDF that preserves transitions.

Re:Keynote

[Val314 (219766)]

PDF would be a better choice...

Ctrl-Click or Right Click

[josephtd (817237)]

Gives you a popup when done in cinjuntgion with mouse over the presentation. At least it does in Safari.

Re:Ctrl-Click or Right Click

[rthille (8526)]

Yeah, I tried that. But selecting 'Back' from the resulting menu had no effect. (10.3.9, Safari 1.3 v312)

Re:Eek, a presentation in flash!

[macshome (818789)]

Erm, right click > Back seemed to work for me.

Didn't work for me, though :-( (Safari 2, 10.4.1)

[Psychic Burrito (611532)]

Bummer :-(

Worthless filesystems.

[Given M. Sur (870067)]

So HFS+ can only support file sizes up to 8 exabytes. What a worthless filesystem.

For explanatory purposes

[by Anonymous Coward]

"Largest file size is 2^63 bytes"

Pedantic note:

• 2^63 bytes == 9007199254740992 KiB

• 9007199254740992 KiB == 8796093022208 MB

• 8796093022208 MB == 8589934592 GB

• 8 exabytes == 8*(1,024*1,024*1,024) GB == 8*1073741824 GB == 8589934592 GB

____

Now my head hurts

Re:Worthless filesystems.

[Chucker23N (661210)]

And here I was, hoping HFS+ would provide the means to fit all my pr0n on it.

Re:Worthless filesystems.

[by Anonymous Coward]

You must be one hell of a pornophile if your files are larger than 8,589,934,592 GB.

Re:Worthless filesystems.

[Chucker23N (661210)]

I have desires and wishes to be satisfied.

Re:So, HFS+ can be case-sensitive...

[ahknight (128958)]

Like this: http://www.codepoetry.net/archives/2003/10/26/case sensitive_hfs_for_the_masses.php [codepoetry.net]

Re:So, HFS+ can be case-sensitive...

[macshome (818789)]

Just use diskutil on 10.3 or Disk Utility in the GUI on 10.4. Josh

Embedd C++

[bhima (46039)]

I find it interesting that parts of the Kernel were written in Embedded C++. I haven't had the opportunity to use this although I'd love too. Anyone have an experience with EC++ they'd like to share?

Re:Embedd C++

[Nuuskis (686533)]

Embedded C++ is upwards compatible subset of ANSI Standard C++. So if you have written very simple C++, for example when coming from C and making your first C++ program, you probably "used" EC++. It is just C++ without namespaces, templates, exceptions, RTTI (Runtime Type Identification), STL (Standard Template Library), and some other stuff that might make executable noticeably bigger and cause unwanted memory consumption.

* Encrypted swap (optional, uses AES)

[VValdo (10446)]

Wow.. So it looks like they finally fixed this security bug where the password could be discovered in the swap. Anyone know how to turn this feature on? (don't have Tiger yet & a quick Google search turns up nothing)

In the same vein, I recall OS X versions up to jaguar had weakly-hashed user passwords in a SAMBA directory somewhere. If I'm remembering correctly, can someone verify that this is no longer the case in Tiger?

W

Re:* Encrypted swap (optional, uses AES)

[kerry-buckley (647774)]

Wow.. So it looks like they finally fixed this security bug where the password could be discovered in the swap. Anyone know how to turn this feature on?

There's a "use secure virtual memory" checkbox in the security preference pane.

Re:* Encrypted swap (optional, uses AES)

[68kmac (471061)]

It's an option in the "Security" panel of the System Preferences.

Re:* Encrypted swap (optional, uses AES)

[macshome (818789)]

You turn on encrypted swap in the Security prefs. I know of some people doing netboot with encrypted local swap for security.

Hashing is now selective again. If you don't need SMB access for an account it won't make the NTLM hash.

Re:Bad SWF file?

[cide1 (126814)]

I got that under firefox, it works fine in IE

Re:Bad SWF file?

[BrianPan (786919)]

Looks ok in Opera on Windows, too.

Re:Bad SWF file?

[aristotle-dude (626586)]

Maybe you have Flashplayer 6 installed instead of Flashplayer 7?

Flash under Windows

[koehn (575405)]

I take it nobody with a Windows box even tried to view the presentation. All of the space characters are rendered as "x20", which makes it a bit tough (nee impossible) to read.

Re:Flash under Windows

[Gulthek (12570)]

Not here at work: Windows XP on a stock IBM. The presentation ran fine.

Re:Flash under Windows

[koehn (575405)]

Weird. I'm running XP SP2 on a stock HP, and no such luck. Guess I'll try it from my Mac when I get home.

Re:Flash under Windows

[BiOFH (267622)]

Well, that?s unfair. I mean it?s not like Mac users have had to put up with anything similar from Window?s non : standard character set choices. ;)

Re:Flash under Windows

[koehn (575405)]

The space character (0x20) is the same on both platforms, however. At least MacOS X switched to a more "standard" line terminator (\r\n), however inferior I might feel it is to it's MacOS = 9 equivalent (\r).

Character encoding is truly a bane of modern software. It's kind of like Y2K, but it keeps going on forever, since nobody is going to bother switching legacy systems to support Unicode (and even then, you have multiple choices for encoding).

Re:Flash under Windows

[mollymoo (202721)]

All good here on Win2k w. Firefox & Flash7.

Re:AES encryption under the hood?

[zhiwenchong (155773)]

Apparently not:
http://en.wikipedia.org/wiki/AES#Security [wikipedia.org]

Re:AES encryption under the hood?

[by Anonymous Coward]

You're wrong.

Maybe you're thinking of the old DES standard.

http://en.wikipedia.org/wiki/Data_Encryption_Stand ard [wikipedia.org]

Re:AES encryption under the hood?

[by Anonymous Coward]

FS and swap encryption is used to encrypt user's home directories. This is the "File Vault" functionality of OS X. Tiger adds the ability to optionally encrypt the users swap space also (only on file vaulted home folders) to secure the users memory space as well. A file vaulted home folder becomes a sparse disk image file (a disk image that can grow in size as it's written too) that uses the users account password to open. If the user losses their account password then the admin can use the master file vaul

Re:NSA deciding how to break into Mac computers?

[noewun (591275)]

Sorry to dint your tinfoil body suit, but the reason the NSA is interested in OS X is because they use OS X. I have a very interesting, very thorough PDF authored by the NSA (report #I331-009R-2004) on how to secure an OS X box, from install through end use. Very interesting, and I learned a bit.

Re:NSA deciding how to break into Mac computers?

[wirelessbuzzers (552513)]

The NSA is not allowed to break US laws. Of course, they spy on other countries, so they're probably allowed to break other countries' laws.

As for the other nasty stuff, it sounds an awful lot like your tinfoil hat is on too tight.

Also, if you want to hack a computer, you probably care more about the services running on it than the guts of the kernel, at least up to the point where you install a rootkit. They probably care more because they want to use MacOS X in a highly secure environment. SEDarwin a

Shocking ignorance of U.S. government activities

[Futurepower(R) (558542)]

It's shocking how ignorant people are of the activities of the U.S. government. Look at some of the other replies to the parent post.

Most openly managed organizations have great difficulty staying on track. Secret organizations develop bad habits very quickly. In secret organizations, cover-ups become habit. Even the cover-ups themselves can be kept secret from other people in the same organization.

Supposedly, U.S. spy agencies are not allowed to break U.S. laws. However, organizations that hire peopl