Now blogging at diego's weblog. See you over there!

clevercactus beta 2

Lots of improvements, fixes and new features coming up for clevercactus beta2. Because an image is worth more than a thousand words (and because I won't be able to write a thousand words), here's a screenshot. In it, among other things: the new tabs (the tabs are back! :)), the new horizontal layout, and display of a necho feed (actually, Mark's prototype necho feed). And, before anyone starts on how the horizontal three-pane view is bad, here is a screenshot taken a few seconds later but with the "standard" view; the layouts can be switched on the fly (through the View menu). New things in different areas, too (and the screenshots contain a hint of another upcoming feature...).

So, more updates soon! In the meantime, back to work. :)

Categories: clevercactus
Posted by diego on July 9, 2003 at 9:48 PM

redefining the term "computer virus"

In a comment to my previous entry on linux/unix viruses, Jim said:

Well that's what you get for mixing up your terminology. It used to be that "computer virus" referred to something that spread due to user action (as opposed to "worm" which does not require human intervention). Now it's just a catch-all for anything nasty that happens to a computer.

A virus, in the classic sense, cannot affect unix-like systems very well, since it's extremely rare for executables to be writable by normal users or transmitted between machines.

Worms, on the other hand, are typically spread through network services, and are not bound by normal restrictions or usual use patterns of users.

Yes, it's possible to create ELF viruses. No, it's not a problem in practice. It's valid to say that unix-like systems are resistant to viruses in the extreme, whilst acknowledging that they are still susceptible to worms. Anybody who conflates the two issues, as the author of this article did, needs to learn a thing or two.

I realized that I should clarify when I wrote the post; that is, that I think that what we call "computer virus" has evolved--then I simply forgot. Well, now it deserves its own entry. :)

Jim is technically correct as far as current terminology is concerned, but in practice I disagree: the differences we used to give to "worms", "trojans", and "viruses" no longer apply. They're all viruses. Let me explain.

I was thinking of "viruses" as the word is used in biology. Quite simply, any organism that can self-replicate, but that requires a host (host in the biological sense) to survive (as well some "function" of the host to self-replicate). The fact that we called viruses those that self-replicated through (say) EXE infection and that we call worms those that self-replicate through, say, an Apache bug, is simply a historical quirk. Mostly, in general terms, we were making the distinction between infection that required humans (ie., X sending Y an infected file, Y executing the file and thus infecting the system) from infection that didn't (like most internet worms these days, e.g., SQL Slammer). Probably one problem is that we tend to associate virus with sickness (and worms have been so far bothersome but not overly destructive), but not all viruses create problems, and in fact it's been speculated that they are an important element in allowing information flow within the gene pool of a species, and even cross-species. (Not that computer viruses are useful for this too, but wouldn't that be nice... :))

In reality, if we are going to borrow the term virus from biology, it's the worms that should be called viruses, since they can self-replicate across hosts, and in any case most if not all viruses these days have "worm" qualities mixed in. A good example are outlook viruses: they can transfer autonomously, but require human activation (running the executable file).

Probably the article's author should have made this clarification, but I think that it's about time we put the all these different categories together.

So, in my opinion: worms, viruses, trojans... They're all computer viruses, if we understand viruses as akin to their biological cousins. Some are more effective than others at self-replicating and transfer across hosts. But they all belong to the same "family" of "organisms". :)

Categories: technology
Posted by diego on July 9, 2003 at 11:46 AM

viruses in linux/unix

Interesting article on viruses in Linux/UNIX. It reminded me of something that I had forgotten: the first worm (a.k.a "mostly harmless" --to quote Douglas Adams-- networked virus) ever launched was a UNIX worm, in 1988, and it could also be argued that it was the first virus to be globally effective.

Categories: technology
Posted by diego on July 9, 2003 at 8:14 AM

a new particle

I didn't see anything about this last week in other places (or maybe it hasn't been widely reported?), anyway: a new particle, the pentaquark, has been found. Quote:

James Joyce would have been delighted. Quarks, one of the basic building-blocks of matter, were named in the 1960s after a line from his novel “Finnegans Wake”—three quarks for Muster Mark!—because they were then thought to come in three types (the number is now known to be six). Protons and neutrons, however, do consist of three quarks each. And physicists have now discovered a particle that is made of five quarks—a bit of a promotion for Muster Mark.

Categories: science
Posted by diego on July 9, 2003 at 12:30 AM

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