Build numbers - what do they mean?

[hazmat]

What exactly do the build numbers of the OS mean?

Thanks.

 

[simX]

Basically it's a way for developers to differentiate different internal builds of Mac OS X released to them. Sometimes Apple creates nightly builds, so they need a way to keep the versions separate as well as a way to show how much work has been done on each version.

To the end user, the build numbers usually don't mean much. But to the developer, sometimes it's very important to know if you're using build 5Q25 of OS X 10.1.3 or 5Q45 of OS X 10.1.3, and it might help Apple support, too.

You can also see how much work has been put in based on the build number. After the April 2002 Security Update, the build number went from 5Q25 to 5Q45 (I think), so you can see that there's a bit of change in there. In contrast, OS X 10.2 is up to 6C35 or something, and you can see that there is much more work gone into these builds because the build number starts with a 6 instead of 5.

I don't think it's anything beyond this. The letters don't mean anything specific – it's just a different naming scheme.

 

[hazmat]

Thanks, simX. Yeah, I know about build numbers, but was wondering more what the 5 or 6 and the letters meant.

 

[nkuvu]

It could very easily be similar to the dot dot notation for version numbers. The leftmost number is a major change, the letter is a more minor change (and a separator so you know it's build 6-C-35 as opposed to perhaps confusion between build 6-33-5 or build 63-3-5) and the rightmost number is the least significant change.

This is all just a guess, btw...

 

[lethe]

also just a guess, but maybe the 5 in the current build number corresponds to the 5.x darwin version we are running. so maybe jaguar has a 6.x darwin kernel.

 

[starfleetX]

Originally posted by nkuvu
The leftmost number is a major change, the letter is a more minor change

Correct.

for example:

4xxx was Cheetah, aka 10.0.
5xxx is Puma, aka 10.1.
6xxx is Jag-wire, aka 10.2.