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Sun CEO Says ZFS Will Be 'the File System' for OSX
Fjan11 writes "Sun's Jonathan Schwartz has announced that Apple will be making ZFS 'the file system' in Mac OS 10.5 Leopard. It's possible that Leopard's Time Machine feature will require ZFS to run, because ZFS has back-up and snapshots build right in to the filesystem as well as a host of other features. 'Rumors of Apple's interest in ZFS began in April 2006, when an OpenSolaris mailing list revealed that Apple had contacted Sun regarding porting ZFS to OS 10. The file system later began making appearances in Leopard builds. ZFS has a long list of improvements over Apple's current file system, Journaled HFS+.'"
Jobs is probably not happy about his thunder being stolen right before for the June 11th keynote
I strongly doubt he didn't know about it. This is Jonathan Schwartz, not a OS X rumors blogger. At any rate, ZFS in OS X is Sun's thunder; Time Machine is Apple's thunder, and that's already announced. How many OS X users (other than slashdot readers) will care in the slightest about the underlying filesystem? What they care about are the features, like Time Machine, that it enables.
If ZFS is the default file system, it will mean that Time Machine (i.e. the snapshot feature) of 10.5 will be able to take snapshots without requiring a secondary file system to keep the copied (recoverable) blocks, as it does now with HFS+. To me, the secondary filesystem requirement makes Time Machine essentially useless on a laptop.
I think Slashdot would benefit from adopting some of K5's approach to story submissions. The Firehose is a great start, but instead of simply saying yes or no, users should be able to give feedback to the submitter. The summary for this article is a great example. The submitter typed "build" instead of "built," resulting in an annoying distraction in an otherwise concise description of the story.
Newspapers have Copy Editors (at least they used to; most seem not-too-bothered by spelling these days). It would be nice if interested Firehose users were given the opportunity to help make sure the summary was fit for publication before it hits the front page.
I guess this should have been a journal entry, but it seemed like an opportune time to bring this up.
I don't care why you're posting AC
This will make going from earlier versions of OSX to the new one more of a pain because the whole disk will have to be reformatted.
and since apple has all the rights and source to HFS(+)(Journaled) they can just as easily write a windows driver for it as well.
Don't call me back. Give me a call back. Bye. So yeah. But bye our, well, but alright we are on a shirt this chill.
Apple is "well known" for massive backwards compatibility updates... except they aren't... They always handle transitions over a couple of versions, intelligently bringing people along. They swapped processor architectures twice and each time brought people along with emulators, in the Intel case it wasn't faster than the fasted G5 machines, but those of us upgrading 3+ year old machines (Powerbook G4 1Ghz -> Macbook Pro in my case) found our PPC apps running faster and Intel code flying.
We all expected the Intel migration to happen with 10.5, they shocked us when they did it off the 10.4 base.
While they did abandon Mac OS to move to OS X, they provided a migration strategy (Carbon) and a compatibility layer (Classic). Classic support shipped with 10.0/10.1, 10.2, and was supported in 10.3 if you already had it, as well as 10.4 I think, but they kept classic for around 5 years, which gave everyone time to migrate to Carbon. Its unfortunate that there is no long-term Classic via Rosetta just from a classic application point of view, but they didn't leave anyone in the lurch.
I expect 10.5 to introduce this OS, which will be useful for new installs, or for external drive arrays, especially for the Video market, but I wouldn't expect it to be the default. OS X has supported a Unix filed system, but defaulted to HFS+, because HFS+ was compatible with Mac OS, so you could dual-boot OS 9 and OS X for a good 2 years on new hardware to maintain compatibility. If they hadn't done that, they would have lost the Pro-Audio and Pro-Video markets that took a few years to get native OS X applications.
Getting it in the wild and for professionals would help that market, while not breaking ANYONE's compatibility. Sometime in 10.5's lifetime they may ship new computers with it, or they may wait for 10.6 in two years. But giving everyone two years is plenty of time to get utilities and applications compatible with the new file system.
The flashy consumer features are touted for the OS, but the underlying architecture has always followed a 2-cycle release. If you've used OS X Server for 10.2/10.3/10.4, you'd notice that they introduced stuff in one version with limited exposed functionality (with the rest via the Unix layer), enhanced the functionality in the next rev, and polished thereafter.
The Apple Mail Server -> Cyrus migration was someone poorly handled, but mostly because AMS was garbage. But the 10.4 Mail tools are night and day beyond the 10.3 ones.
They are actually far more careful than people give them credit for.
The different is, they don't keep backward compatibility as a long-term goal, they do a two-stage migration, giving people 2-4 years to transition.
You can't restore the original case of a string afterwards, but you can always make it lowercase. This is called "case folding." You can fold two strings to a lowercase form, and then compare them for equality or whatnot. Works with Unicode, too. Then there is the issue of internationalization. For example, consider "I" and "i". Some places have an uppercase with the dot, and other places have a lowercase without the dot. The rules for uppercasing and lowercasing differ from what most people are used to. Oh crap! This issue doesn't exist on a case-sensitive filesystem. While folding Unicode chars is frequently presented as an unsolvable problem ("what do you do with the letter with the squiggly thing above it? Or converting that German capital 'B' thing to two lowercase 's' chars? There are MILLIONS OF THESE!")
Here's the whole list of characters that need to "folded" to a lowercase form, accounting for instances where it will cause the string to grow (like that German 'B' thing):
http://www.unicode.org/Public/3.2-Update/CaseFold
(And you can hash those chars too, so folding a string doesn't involve hundreds of conditionals.)
If you don't care about Unicode, case folding an English ASCII char is 2 lines of C code, and a few more if you want extended ASCII.
Once you have a filename, you can store it in the filesystem as the specifically-entered characters, so you don't lose the original casing, but also store with it a hash of the case-folded version. Now whenever you need to look up a specific filename, you case-fold it, hash that folded string, and look it up that way against the hash you previous calculated when creating the file. Now it's as fast as the case-sensitive filesystem, minus the overhead of folding a small string. Because of the way directory listings are done (read then look up stats) you can generally square the above numbers. Ouch. The way directory listings are done doesn't change...readdir() is the same in all cases, and your lookup is still a hash. If you had to scan, the first run is slow anyhow due to disk bandwidth and seek speeds, but then a modern OS can cache the inodes to speed this up for the next run. App needs to make a file. App sees that file does not seem to exist. App writes file. Complex international case rules mean that no, the file DOES exist, and it gets clobbered. I would think that stat(filename) would not report the file doesn't exist if open() would then clobber it, at least not for case-sensitivity issues.
If your app decides about a file's existence by using readdir() until it finds it, and doesn't properly case-fold, and didn't call open() with O_EXCL, then not only did you go the long way about it, you got what you deserved for clobbering the file.
Actually, if you don't just open(O_CREAT | O_EXCL) to check for existence and create if missing in one step, then you'll have an atomicity problem anyhow. Use the services the OS provides, they are there for a reason.
--ryan.
Don't say, "don't quote me," because if no one quotes you, you probably haven't said a thing worth saying.
So, how exactly does one roll back changes to a file on an NTFS partition?