Wandering Thoughts archives

2008-12-09

What sort of user interfaces the web is good for

Here is a corollary to what standard interfaces are good for, in the form of a thesis:

The web excels at standardized interfaces, but requires increasingly heroic amounts of work for excellent customized ones (once you want to step out of what the browser gives you). This implies that web applications are a natural fit for occasional usage things, where any awkwardness of the web interface is overcome by the advantage of not having to learn yet another custom interface that you use for ten minutes once every month, or for things where the natural web interface is a great fit for the task, but they are not a good fit for anything else.

(For example, Google Maps is very nice, but in a sense it is a bear dancing. As Google Earth demonstrates.)

This raises the obvious question: what things are a natural fit for the normal web interface? I think that the answer is filling in not too large forms, or at least forms with relatively little interaction with the system (for, eg, immediate error checking on some fields), and navigating through information in relatively simple ways that have only a few choices. Usefully, I think it turns out that there are a lot of applications that don't want to do much more than that.

(This suggests that one reason that people actively like web applications over their old non-web versions is that they were sick and tired of programmers coming up with yet more interfaces for what was fundamentally filling in forms and doing basic information navigation. Possibly this is an obvious corollary.)

web/WebInterfaces written at 20:18:52; Add Comment

How Amanda uses what restore program to use, a correction

In AmandaRestorePrograms I wrote, about what to do if Amanda didn't recognize properly recognize which sort of dump program it had used to back up a filesystem:

  • put a 'restore' program (either a cover script or just a symlink to ufsrestore) somewhere in our $PATH when we do Amanda restores.

Allow me to correct myself: this doesn't actually work as I wrote it. (When I wrote the original article, we hadn't had to actually test this; we have since then.)

The problem is that Amanda does not actually search $PATH when it is executing the restore program (including when it is plain 'restore'); it simply executes the program directly by path (which is sensible, since it normally knows the exact path). When it tries to execute the default restore program it uses no path, and thus is actually trying to run './restore'.

(In Unix terms, Amanda uses execve() instead of execvp() or the like.)

So: you have to put your 'restore' program in the current directory (possibly in the directory that Amanda will restore to, if you've changed that inside amrecover). This does work, although it's slightly inconvenient.

sysadmin/AmandaRestoreProgramsII written at 14:06:28; Add Comment


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