Executive Summary: Internally, SuperDuper! can now make bootable copies of "live" Catalina volumes in all three released Beta versions of macOS 10.15. While much work still needs to be done to make things ready for external use, no obstacles are blocking us from pursuing at least one "definitely works" path.

Right up front, allow me to understate something: booting macOS is definitely not getting simpler.

When things change, as they have in Catalina, I've got to delve into what's going on using a combination of on-disk evidence, boot-time kernel logging, and trial-and-error.

When things fail, there's no persistent evidence, so I also spend a lot of time taking pictures of a rapidly scrolling "verbose boot" screen, watching what the kernel is shouting before it fails the boot and shuts down.

A lot of it is kind of tedious work, and there aren't any CSI-style glass panels and black lights to make it look more exciting and cinematic. It's just a bunch of screens and drives and cups of coffee and notes. It looks a bit like a conspiracy theory evidence board. With a crazy-looking person doing the same thing, with minor modifications, over and over again, usually to failure.

Oh-No-Dependent

But, sometimes, to success! And we're now at the point where we have a definite path forward that isn't gated on things we can't control.

That latter issue is a big deal in this business.

When there are bugs or limitations in frameworks or tools or whatever that can't be worked around, it reflects poorly on the product that depends on them. And so we've endeavored to do as much ourselves as we can, to ensure we're not overly coupled to things that have proven to be problematic.

For example, in a previous post, I mentioned how our sparse file handling is much faster than what's built into the system (copyfile) and a typical naïve, cross-platform implementation (rsync). Had we been dependent on either, it would have been much harder to improve the speed as much as we did.

But since we wrote and use our own copy engine, we were able to extensively optimize it without waiting for system-level improvements.

Of course, that has its own potential downsides (copyfile, an Apple API, should handle any OS-level changes needed, but has proven over the years to be buggy, slow, etc), so a careful balance needs to be maintained between dependence and independence. Being more independent means you have to track changes carefully and update when necessary. Being more dependent means you may be broken by factors outside your control...forcing you to rewrite things to be more independent.

Tradeoffs. Whee.

Doing the Right Thing

Last post, I mentioned that we had considered putting in "quick-'n-dirty" Catalina support to try to have something, given the public beta was imminent.

That was going to basically "combine" the two volumes—System and Data—into one, recreating the "old" structure. It was bootable, and "worked", but the problem was with restoration: if you wanted to restore more than just a few files, you would have had to clean install Catalina and migrate from the backup.

That is, basically, what you have to do to restore from Time Machine (it's handled for you), so we decided it just wasn't offering enough of a benefit beyond what Apple was going to provide, especially since we just wouldn't have enough time to test against all the different scenarios involved.

So, we decided to take the "hit" of not having something available, rather than have something "not good enough".

I know that's frustrating to users out there using these early Catalina builds, but, frankly, if you're jumping on early betas you know what you're in for. We're working hard to have a real solution available as soon as we can.

3.2.5's Continued Success

The new public version of SuperDuper continues to perform really well. The biggest issue we've seen is that some people are running through the "old" purchase process on an old version of SuperDuper, rather than installing 3.2.5 and purchasing in the app or the web site. But I can fix that up as soon as they contact me at support.

So, if you have a problem, contact me at support...

Forecast: Brighter Days Ahead

We continue to work to produce a version of SuperDuper! that's usable by "regular users", with a quality level appropriate for a Beta version. Good progress is being made, the path is clear, and now it's just a matter of writing, debugging and testing the rest of the code.

That's not a small task, of course. But it could be a lot worse!

More as there's anything interesting to add...