No, my problem is still not solved, but I thought I'd take the opportunity to say a few things about Ubuntu Linux as an environment in which to work and play.
- From a user standpoint, Linux is not Windows. And it is not the Mac OS, though there are similarities in any two *-nix-based systems. Windows users will find that things are not in the same places, and many things do not work the same. If you do your own system administration and maintenance, familiar tools are missing, and others take their place.
- That said, most familiar tools, apps, games etc. have more or less exact equivalents in the Linux world:
- notepad becomes gedit in Linux;
- the Firefox browser and Thunderbird mail/news software have exact equivalents (and I do mean exact) in Linux;
- the OpenOffice.org office suite, authored by Sun and used by Sun, HP, Dell, IBM and other familiar names, is a functional equivalent of Microsoft Office Word, Excel, etc., even to the point of reading/writing the same file formats if you wish;
- the games are simpler and a bit slower-running than those on Windows, but Solitaire, Mahjongg and Tetris are all present in some form (sometimes in many forms);
- Both simple and high-powered graphics editing software is available; some say that gimp beats PhotoShop, though I'm not one qualified to confirm that;
- There's a simple photo manager, FSpot, that will exasperate you if you are accustomed to the Microsoft tools.
The good news about Ubuntu Linux (and many other, um, Linuxes? Linuces?) is this: everything is free... almost all software support is available without cost to the home user. This is a philosophical decision by the foundations that produce the software.
The bad news about Linux is this: everything is free. If you as an end user need support on a software product, you put your name in the queue and wait until someone with expertise recognizes your problem and feels like answering you. For my one big problem so far, I have received no answers in several days... none. Commercial support is available if one wants to pay for it. The whole concept is unfamiliar to (former) Windows users.
A lot of times, the problem emerges from the home-brew software that so typically fills the gaps in the operating system as shipped. For example, there is no intrinsic backup software in Ubuntu Linux, and you are pointed to a freeware product called Simple Backup Suite for what would be a rather nicely turned backup system with facilities for automation, etc. ... if it worked properly. Instead of working properly for me, it broke my filesystem; I have lost access to about 80 percent of my hard drive. Such is the cost of free software. Of course, all this free software is supplied with source code; I actually waded through reams of Python source in an attempt to find what, in the backup software, was wrecking my home. No, I didn't find it. But the source code is there, as is the legal license to modify it, if one feels inclined to a do-it-yourself approach... and if one is a developer by trade, has an environment set up for doing the job, etc. etc. Good luck.
Is Ubuntu (or any other) Linux a suitable free replacement for Mac or Windows in a business setting? Only if you have a support staff and environment equal to the task. It is cheaper to install, but no cheaper (and no easier) to support. I'd think long and hard before I committed a business of any size to a Linux-based network. Then again, there are the examples of IBM, HP, Sun, etc. There's no one answer: as in the rest of the real world, you have to evaluate by your own criteria and live with the decision you make.
I'll write more on the subject as it occurs to me.
UPDATE: The solution to my problem began with a reboot, a rare animal in the *nix world in my experience. Apparently, the memory image... but not the disk content... of the part of the filesystem containing the backup directories was somehow corrupted. A reboot (at least; other things I did may have had some effect) allowed me to see the previously invisible backup directories and to use 'sudo' to remove the files and then the directories. I have about 85GB (or 85 GiB, as it seems to be known in this universe) of free space now, having kept two of the full backups, one from yesterday and one from the beginning of June when I started this unplanned OS transition. For an old machine, 85 GiB is quite a bit of elbow room, especially given my reduced picture-taking habits these days. It's a good thing I don't have one of those new 20+ megapixel dSLR's...