> I started wondering why all software, without exception, isn’t written this way by default.
This is a very interesting question. I'm pretty sure it's pure "technical debt"; we're still so conditioned by extremely slow storage devices (the floppy is still the canonical "save" icon, remember?) that nobody questioned this sad state of affairs.
It became suddenly obvious that all and every application should continuously save its state, so that you would need to name your files only to better find them. A whole new paradigm waiting to be implemented, fully orthogonal persistence ( http://en.wikipedia.org/wiki/Persistence_%28computer_science... ).
Snow Leopard made the very first step toward it: when your app is in a consistent, everything-persisted-that-needs-to-be state, it can set a bit that tells the OS that it can just kill -9 it at will.
I feel like I remember Jef Raskin talking about this in his Hamane Interface book, the idea that there should be no saving and that everything should always have infinite undo (all as a goal). I might be wrong about that.
> It became suddenly obvious that all and every application should continuously save its state
I'm not so sure. Continuous saving is one of those ideas that sounds great until you actually do it, but then you realise that saving isn't just about persistence, it's also somewhat about marking a meaningful checkpoint in your work.
Take a look at Google Docs, for example. Open a spreadsheet, edit a few things, hey, great, I can go back to every previous edit in the history of the document. Two months and thousands of edits later, all those early edits are completely and utterly useless, but it puts a horrible drain on the UI because you don't have (for example) separate copies that you saved from when you distributed draft 1 of the sheet and when you distributed draft 2, which are the only milestones you really care about by now.
The idea isn't even that great in the short term, because any usefulness in being able to jump back to work from a couple of days ago is swamped by the awkwardness of having to navigate through every single edit you've made since then to get there. Give me a real document control system and my Ctrl+S reflex any day.
Orthogonal persistence doesn't enforce unlimited undo, nor does it forbid a "save a copy as" option. Both may make sense (or not) depending upon the task or application.
Take "Crash-Only" one step further and you get apps that back themselves up automatically. Re-install the app on your new device and it restores all of your data.
This is a very interesting question. I'm pretty sure it's pure "technical debt"; we're still so conditioned by extremely slow storage devices (the floppy is still the canonical "save" icon, remember?) that nobody questioned this sad state of affairs.
It became suddenly obvious that all and every application should continuously save its state, so that you would need to name your files only to better find them. A whole new paradigm waiting to be implemented, fully orthogonal persistence ( http://en.wikipedia.org/wiki/Persistence_%28computer_science... ).