Totally confused about Sandbox

[CaptSaltyJack]

I'm pretty techie, but I'm having trouble understanding how this works. I've read the user guide, I still don't get it.

So let me get this straight, regarding the process:

1) Boot your main drive (Mac HD), and run Super Duper
2) Run the Sandbox operation in SuperDuper (shared users & apps) and it copies Mac HD to another HD called Sandbox
3) Now you boot the Sandbox volume and use that as your day-to-day drive
4) Weeks pass by, maybe months..then suddenly after a system update, your system is toast.

Now the problem is, my Mac HD system files are way way out of date. If I boot to the Mac HD, sure, the bad update that hosed me is gone, but so are the 50 other system apps and other stuff I've installed since then!

I also don't understand this, from the user's guide:

Need to update an existing Sandbox? No problem! SuperDuper’s amazing
Smart Update feature will update it in minutes. Simply boot back to the
original and follow the steps above, substituting Smart Update from
Macintosh HD to Sandbox for Erase Sandbox, then copy files from
Macintosh HD. SuperDuper will automatically check each and every file and
directory on Macintosh HD and Sandbox, copying any files added or changed
on Macintosh HD to Sandbox. Any files that are on Sandbox that aren’t on
Macintosh HD will be automatically deleted.

Huh? If I've been using the Sandbox volume for a while and ONLY the Sandbox, why would I want to boot the Mac HD and update to Sandbox? It would overwrite any non-user files I've updated.

Someone help clear this up for me. I just don't understand it. And I also don't get: why use the Sandbox as the day-to-day boot drive? Why not just dump to Sandbox, and keep using Mac HD, update to Sandbox once in a while, and when Mac HD gets toasted, boot Sandbox and update to Mac HD?

[dnanian]

The general idea is that you update the main drive from the Sandbox when you know things are working (or you install the things you were 'testing' on the Sandbox). Both operations are explained in the User's Guide.

You want to run from the Sandbox when you're doing something 'risky'. You don't really have to run from it everyday unless you're installing risk stuff every day.

[CaptSaltyJack]

Hmm, ok. But a regular SuperDuper backup can also act as a sandbox. If I'm wary of something, I can just boot the backup and install whatever, to see if it works. Sandbox seems like the exact same thing as a regular backup, except that user files & apps are shared from the Mac HD to the Sandbox in real time, correct? Question: if I boot the Sandbox and install an app, it's not shared back to the Mac HD, right? In other words, it's a 1-way share?

Ok, so basically I still use the Mac HD most of the time, I can just use the Sandbox volume when I want to try something I'm wary of. The user guide kinda makes it sound like you should use the Sandbox volume all the time, which threw me off. In case you're curious, this is the part that made it sound like the Sandbox becomes your full time boot volume:

With SuperDuper, you actually use the Sandbox as your startup
volume.

You can safely install any system updates, drivers or programs in the
Sandbox, without worrying about what might happen to your system. If
anything goes wrong, you can simply start up from the original system.
SuperDuper has preserved it in its original, pre-disaster state – but all your
new and changed personal documents are totally up to date.

Especially the part about "but all your new and changed personal documents are totally up to date." Why would I be making a bunch of changes to my documents on the Sandbox volume if I just booted into it to test out an install? That makes it sound like I'm actually doing real work in the Sandbox, and it's become the volume I boot into to get stuff done. Even worse, what if I ran something on the Sandbox volume that was malicious and wiped out a bunch of my personal files? Now those files are missing on Mac HD? Of course that's probably a rare scenario, but still.

This is also confusing:

Of course, the original volume doesn’t have any of the programs or system
updates that you might have installed since you made the copy. That’s a
good thing, since they’re probably what caused the problem in the first
place!

Why doesn't my original volume have programs I installed? I thought apps and user files are shared? After all, above it says "all your new and changed personal documents are totally up to date" [on the Mac HD main drive]. So if I chose "shared users and applications," then potentially bad apps from Sandbox would also be shared over to Mac HD too?

[dnanian]

No, a regular backup can't do the same thing. If you receive mail, for example, or work on a document, if you restore the backup you'll lose the changes you've made. And, if you're testing out an update, or a new OS version, you might be testing for a few days, and you'd probably want to get some work done.

3rd party apps are shared at the time of sandbox creation, but /Applications itself is not shared. A new install on the Sandbox will go onto the Sandbox volume, and thus won't be on the original drive.

[CaptSaltyJack]

Originally Posted by dnanian

No, a regular backup can't do the same thing. If you receive mail, for example, or work on a document, if you restore the backup you'll lose the changes you've made. And, if you're testing out an update, or a new OS version, you might be testing for a few days, and you'd probably want to get some work done.

Ahhh ok, makes total sense. Thanks!

Originally Posted by dnanian

3rd party apps are shared at the time of sandbox creation, but /Applications itself is not shared. A new install on the Sandbox will go onto the Sandbox volume, and thus won't be on the original drive.

Ok, so apps are shared at the time of sandbox creation, but not afterwards? If I install an app on Sandbox, it won't share to Mac HD.. BUT, what if I install an app on Mac HD, will it get installed on the Sandbox?

[dnanian]

If you update the Sandbox after (with Smart Update, as explained in the quote you posted above), yes.