I'm curious as to why the documentation for Qrecall (and its UI) uses terms uncommon to other backup software. For example, in his eBook "Mac OS X Backups" (p.111), Joe Kissell notes that "has a peculiar interface that introduces several unusual terms (such as "capture," "recall," "layer," and "timeline") that force you to think about backups in ways you may not be accustomed to."

I'm curious as to why the developer has adopted these terms. The standard equivalent for "layer" and "capture" is "snapshot," for example. If one wishes to use "capture" as a verb, then why not just use "backup"?

Marc Bizer wrote:I'm curious as to why the developer has adopted these terms. The standard equivalent for "layer" and "capture" is "snapshot," for example. If one wishes to use "capture" as a verb, then why not just use "backup"?

Excellent question!

It was a conscious decision to use different terms because, in the very early stages of development, it became clear that the standard terms ("backup," "copy," "clone," "snapshot," and so on) were inaccurate and carried too many preconceived notions.

We never use the term "copy" because QRecall does not copy files. We don't use the term "snapshot" because QRecall never makes a snapshot of your existing files.

QRecall maintains a database of discrete, individual, unique, blocks of data we refer to as "quanta". A file is a collection of quanta. When you capture a file, it's disassembled into its quanta and added to the database in a manor that never stores the same quanta more than once.

During the capture, a layer is created. A layer is not a "snapshot," it a set of positive deltas that describe what has changed. In other words, QRecall never stores any information about what is, but only what's changed.

I like to think that QRecall is to backups what holography is to photography.

QRecall works more like a modern version control system. And you notice that git never talks about "copying files" or "taking snapshots." git commits new nodes to a repository. The nodes represent deltas, and a repository is a network of nodes that can be used to reconstruct a set of files at a given point in time.

Now we don't object to the idea of "making backups" or talking about "snapshots" of your files, because at the end of the day QRecall is essentially copying files. And all of those positive deltas can be combined to calculate a "snapshot" of your files at a point in time (which is exactly what is happening when you see the "compositing" message in the QRecall item browser).

So if you want, feel free to think of QRecall as copying files, making backups, and taking snapshots. Just remember that that is not what is happening under the hood.

James Bucanek wrote:

So if you want, feel free to think of QRecall as copying files, making backups, and taking snapshots. Just remember that that is not what is happening under the hood.

I appreciate your precision, but in terms of interacting with the software (UX), does it really matter what is happening underneath?

Marc Bizer wrote:I appreciate your precision, but in terms of interacting with the software (UX), does it really matter what is happening underneath?

We certainly like to think so!

James Bucanek wrote:

Marc Bizer wrote:I appreciate your precision, but in terms of interacting with the software (UX), does it really matter what is happening underneath?

We certainly like to think so!

Sorry to persist, but if the user isn't supposed to know what is underneath, why have the UI rely on a terminology that is keyed to what is happening underneath rather than to what the user is experiencing?

Marc Bizer wrote:Sorry to persist, but if the user isn't supposed to know what is underneath, why have the UI rely on a terminology that is keyed to what is happening underneath rather than to what the user is experiencing?

So you don't mis-apply preconceived notions about what's happening.

Besides, the UI doesn't hide what's happening. If you use the upper and lower shades to isolate a single layer, you don't see a "snapshot" of your files that day. You see a positive delta of what changed, which is the essence of layers.