MacOS 27 threatens to bury Time Capsule, FOSS brings a shovel

Software

Apple’s old backup boxes only speak AFP and SMB1, but NetBSD under the hood gives them one last shot

The next major release of macOS looks likely to remove Apple Filing Protocol (AFP) support,
stopping Time Capsules from working… but life FOSS, uh, finds
a way.

The current version of macOS “Tahoe” 26.4 already
has network Time Machine issues, especially for folks using
Apple Time Capsules. It looks like macOS 27 may completely remove
the network protocol they need. However, the Time Capsules run NetBSD
under the hood, and that means that the FOSS world has been able to come
up with a workaround. It’s called TimeCapsuleSMB, and it aims to keep older Time Capsules usable with modern macOS.

It’s eight months since Apple
released macOS 26, and the company’s annual release schedule means that
macOS 27 is looming. Although Cupertino hasn’t told the world much about
it yet, it is warning sysadmins to “prepare your network
environment for stricter security requirements.”

Reading the bulletin, we found it rather clixby:
while it firmly warns that security checks will become stricter, it
doesn’t spell out what products will change or how. Happily, there are
elder Mac gurus out there who interpret Apple’s sometimes Delphic
utterances, and Howard Oakley is
one of the greatest. In a post about networking
changes coming in macOS 27, he translates that it will require TLS 1.2 or above.
(The Register explained
TLS back in 2002, and version 1.2 appeared about six years
later.)

However, he also warns that it could mean the end of AFP, which is basically Appletalk-over-TCP/IP version 3.4.
AppleTalk was the Mac network protocol for file sharing from System 6
onward. In 2013, OS
X 10.9 “Mavericks” made Microsoft’s SMB the default file-sharing
protocol in place of AFP, and it looks like AFP now faces the ax: it was
officially deprecated
in macOS 15.5. To be fair, macOS 26 Macs started
displaying a warning to Time Capsule users nearly a year ago.

Apple introduced the first
model of Time Capsule in 2008, and the fifth-generation
version in 2013. The company discontinued
the whole AirPort product line in 2018.

All generations only support AFP and SMB version 1. That’s the
original version that appeared with LAN Manager in 1987, and we reported
on Samba dropping SMB1 back in 2022.

The good news is that even if Apple kills its original file-sharing
protocol next year, the FOSS community is on the case and won’t let
working kit die. The Time Capsule hardware is essentially a box
containing a Wi-Fi access point and a hard disk, and an Arm chip with
just enough software to share that HDD as network-attached storage.
Apple didn’t write this software from scratch: it picked up and
customized NetBSD for the job. The first four generations of Time
Capsule (flat square boxes) run NetBSD 4, and the fifth-gen devices –
the tall tower-shaped models from 2013 onward – run NetBSD 6.

That gave Microsoft’s James
Chang an opening. Since the devices run NetBSD, it’s possible to
compile a newer version of Samba, and copy it somewhere that the tiny
embedded Arm computer can find it. Teaching such old kit a new trick is
never that easy, though, and he faced a number of challenges, which he
details in the design
section of the project README. Among them are machines that only
have about 900 KB of available disk space – less than 1 MB – and a tiny 16 MB RAMdisk. He settled on Samba
4.8, which dates back to 2018, the same year Apple discontinued the
product line, but which includes the necessary Time Machine support, via
a module named vfs_fruit.

The TimeCapsuleSMB docs are worth a read. We found his descriptions
of how he worked around the hardware’s very significant limitations
impressive. Notably, on the early models, you’ll need
to manually reload the software every time you reboot the Time Capsule.
The final model can do this automatically.

Don’t fret at the thought of backing up to such an elderly spinning
hard disk: iFixit has descriptions of how to replace the drive in both
the early
models and the later
ones too. ®