Well, the evening before a presentation usually I don't go to the restaurant, but I stay at the hotel to have a final rehearsal of the presentation. Usually I also make some final changes to the slides, typically a reordering in order to come faster to the beef, avoiding an excessively long introduction. You can imagine how I felt yesterday night when this happened while I was doing the final work for my presentation at Devoxx:

Well, actually the screenshot has been taken after the thing happened and I recovered it. In reality, the boot disk failed right while I was saving a document and Mac OS X just got stuck. On the reboot in verbose mode a number of worrying messages appeared on the console, then the o.s. properly rebooted; just to freeze a few minutes later. Clearly a severe failure of the disk.

A few weeks ago I made some changes to my laptop, replacing the optical unit (which I almost never use) with another hard disk, using OptiBay. The real reason for the move was the need of more disk space, given that I want to keep with me my entire collection of photos, which allocates several hundreds gigabytes. So I added a 700GB disk to the previous 640GB one. The original idea was to keep operating systems and work stuff on the old disk, and media on the new one.

But since this new huge amount of available space allows to reorganize partitions in the old disk, I also copied the whole workarea to the new disk, with the idea of repartitioning the former disk. I also kept a spare partition with a fresh Lion installation "just in case of need".

It saved me! While I do have backups on an external disk (in case of a catastrophic failure, I would have lost no more than the last hour of work), the problem would have been the time to restore everything - a time that I simply didn't have, unless I spent the whole night on the job. But not sleeping the night before a presentation is a secure recipe for a failure. The immediate availability of an emergency o.s. copy only required to reinstall a couple of applications (fortunately the hotel connection worked fine - it was broken just until the previous morning!). In the end I recovered everything in a couple of hours (including, of course, a further verification that everything worked).

Of course, I had a previous copy of the presentation on a USB stick and I could do with a borrowed laptop. But it would have been hard to recover the demo part, also considering that involved running some Maven builds that, on a fresh computer, require a good deal of stuff to be downloaded from the internet.

Often, when you think of a backup you only think of not losing data. But the cost to pay is also the time needed for the restored. Usually I have a second external disk, identical to the one inside my laptop, which is constantly cloned. My boot disk contains a number of partitions with three operating systems, which would need several hours of work for a fresh installation. The clone allows to be immediately operative. But I kept it at home, since it sounds unwise to me to carry it along, especially during a long trip as the one to Antwerpen. I'll probably rethink this thing.

But there's another question that I can't find a final answer for. What if the disk crashed just a few minutes before or during the presentation? The only solution I see is using a virtual machine with everything preinstalled; but this solution assumes that not only you can borrow a laptop, but one also with VMWare or VirtualBox installed. Which is not so easy.