macOS Tahoe brings a new disk image format • Hacker News Board

Re: macOS Tahoe brings a new disk image format

#101

Post by kccqzy » Thu, Jun 12, 2025, 8:44 PM UTC

jraph wrote: post #10

lucasoshiro wrote: post #4

Nice. But I would like it better if the effort was to support ext4, BtrFS, NTFS and other popular filesystems from the Linux and Windows world...

This article describes a new disk image format (on which a filesystem can be put, APFS in the article), not a filesystem, or did I misunderstand? edit: added the word "image", which I apparently forgot to type. Mentioning the edition because otherwise it would make an answer to this comment difficult to understand.

Yeah and OP was asking, why was effort spent on a disk image format rather than a file system. Seems like a reasonable question to ask.

Re: macOS Tahoe brings a new disk image format

#102

Post by kccqzy » Thu, Jun 12, 2025, 8:47 PM UTC

archagon wrote: post #100

What blew my mind recently was that I could store an APFS sparsebundle on a NAS drive, then mount it over NFS and use it as a plain old APFS volume. Despite the filesystem layering, it works pretty much like a local volume, albeit with a bit of performance degradation. Seems preferable to something like iSCSI for using APFS with network storage. Perhaps this new format would work even better?

Not sure why that would blow your mind, but Apple's old Time Capsule basically mounted a sparsebundle over the network too. And yes I would also guess this new format would work better.

Re: macOS Tahoe brings a new disk image format

#103

Post by archagon » Thu, Jun 12, 2025, 8:50 PM UTC

kccqzy wrote: post #102

archagon wrote: post #100

What blew my mind recently was that I could store an APFS sparsebundle on a NAS drive, then mount it over NFS and use it as a plain old APFS volume. Despite the filesystem layering, it works pretty much like a local volume, albeit with a bit of performance degradation. Seems preferable to something like iSCSI for using APFS with network storage. Perhaps this new format would work even better?

Not sure why that would blow your mind, but Apple's old Time Capsule basically mounted a sparsebundle over the network too. And yes I would also guess this new format would work better.

My experience with NFS file management has been less than stellar, so running a full, virtualized, and performant APFS volume on top of it feels like a bit of a magic trick.

Re: macOS Tahoe brings a new disk image format

#104

Post by pdpi » Thu, Jun 12, 2025, 9:01 PM UTC

whywhywhywhy wrote: post #73

coldtea wrote: post #57

Earlier quoted context omitted.

> 3rd party supporting a file system would be one of the last things on a list of all software I’d ever want a 3rd party writing instead of the OS maker. Given how many people use FUSE, Paragon NTFS for Mac, and similar tools, you're hardly totally representative.

> Given how many people use FUSE What percentage of MacOS users even know what that is. I mean I am in the percent but I know it's sub 0.001

MacOS users' awareness of a mostly linux centric piece of tech is pretty damn irrelevant here. The point is that FUSE is a pretty mature piece of technology, and we know that it can be used productively without being that nightmare scenario you described. There is no reason why Apple's FSKit can't be equally successful.

Re: macOS Tahoe brings a new disk image format

#105

Post by kstrauser » Thu, Jun 12, 2025, 9:01 PM UTC

skrtskrt wrote: post #98

thierrydamiba wrote: post #85

Earlier quoted context omitted.

I have an unusual way of communicating sometimes that used to be quirky and fun. Now I simply get accused of being a bot. Before LLMs I never got accused of being a robot. I think the idea of good writing is soon going to morph with writing that doesn’t feel like it was made with AI.

It drives me crazy that em-dashes are supposedly a smell for AI now. The em-dash is a great and underused bit of punctuation. I am just glad I am not in college dealing with all the AI and faulty AI detection crap happening. Ridiculous false accusations of plagiarism were already awful enough before this.

Same here. It's almost as if LLMs emit em-dashes because the content they were trained on contains them. Wait until skeptics realize how often LLMs use the word "the".

Re: macOS Tahoe brings a new disk image format

#106

Post by johnfernow » Thu, Jun 12, 2025, 9:12 PM UTC

bombcar wrote: post #13

gjsman-1000 wrote: post #9

Earlier quoted context omitted.

Even FreeBSD can't be bothered to do a good job supporting Linux file systems. They're basically proprietary siloed file systems like the rest, even if code is available. Linux, meanwhile, can't be bothered to support either of FreeBSD's file systems officially. UFS2 is hardly patented anymore, but Linux doesn't care beyond read-only support. Being open-source, and even being in a popular open-source project, does no…

There might be some license issues, but the dirty secret is filesystem portability isn't terribly important, and for the users for whom it is - ExFAT and friends are usually good enough.

exFAT is widely used but it not being journaled has led to so many thousands (if not more) people losing tons of data, many of which wouldn't have lost so much data had they used a journaled filesystem (or even one with redundant file tables.)

If you need to connect a portable drive to machines of different OS's, there is no safe filesystem that supports read and write on both Windows and MacOS.

Alternatively, cloud storage works until the files are larger than the space you have left on Drive/Dropbox/OneDrive/etc., and local network sharing (on certain networks at least) is more complicated than what the average user is willing to put up with. In practice, many use USB flash drives or external HDDs/SSDs with exFAT. Yeah, people should have more than one backup, but we know in the real world that's not what many do. That requires them spending more time (e.g. configuring local network sharing or setting up an old machine lying around to be a NAS) or money (more on cloud storage.) In practice, having a cross-platform, journaled filesystem would lead to a lot less data loss.

Aside from exFAT, the only alternative with native cross-platform R/W capability is FAT32, but while it has a redundant file allocation table (unlike exFAT), it has a max file size of 4GB, which limits its usefulness for many workflows.

Re: macOS Tahoe brings a new disk image format

#107

Post by brk » Thu, Jun 12, 2025, 9:16 PM UTC

frizlab wrote: post #52

I have a meta question not directly related to the article but more about HN itself. I posted this exact link 9h before this submission was posted[1]. How is it possible that there is a new entry for the submission given the link is the same? [1] https://news.ycombinator.com/from?site=eclecticlight.co

Might be something weird with this domain. Look at the list of submissions, yours isn't the first dupe that was accepted in a relatively short time window.

Re: macOS Tahoe brings a new disk image format

#108

Post by shakna » Thu, Jun 12, 2025, 9:18 PM UTC

bigyabai wrote: post #2

My kingdom for a documented disk image format.

About the only decently documented disk image format I've found is qcow2. [0] Which is usually not the best tool for the job.

So very many of them are just header details + "only works with our tools".

[0] https://www.qemu.org/docs/master/interop/qcow2.html

Re: macOS Tahoe brings a new disk image format

#109

Post by mrln » Thu, Jun 12, 2025, 9:18 PM UTC

__float wrote: post #92

coldtea wrote: post #57

Earlier quoted context omitted.

> 3rd party supporting a file system would be one of the last things on a list of all software I’d ever want a 3rd party writing instead of the OS maker. Given how many people use FUSE, Paragon NTFS for Mac, and similar tools, you're hardly totally representative.

Do many people use macFUSE? I thought ever since the license change it's really dropped off.