Frequently Asked Questions

What's “.ch”?     Or, “Are you really in China?”
.ch is the top-level domain name for Switzerland. “Huh?”, you say…. Well, though this is a small country (population about 7 million), there are four national languages, in each of which the country has a different name:

German: Schweiz
French: Suisse
Italian: Svizzera
Romansch:   Svizra

On bank notes and official documents there's plenty of room to include all the different languages, but coins, license plates, and domain names lack the real estate so the abbreviation of the Latin name “Confoederatio Helvetica” (Swiss Confederation) is used, which avoids giving preference to any of the national languages. Hence the “.ch” domain name, postal code, and country stickers on automobiles. China is .cn, by the way, and Chile is .cl. But why Switzerland?

What's this Librorum gibberish?    Can't you speak English?
Index Librorum Prohibitorum Can't you speak Latin? Index Librorum Liberorum is Latin for “List of Free Books”, which seemed an excellent title for a site consisting primarily of public-domain software and documents. It is a parody, of course, of Index Librorum Prohibitorum, the list of books banned by the Roman Catholic Church. Liberorum is itself a Latin pun, meaning both free of charge and promoting liberty.
Can I link to your site?
Certainly! You needn't ask permission. Just go ahead and make the link.
Here I am at Fourmilab. Where's the Tevatron?
Oops…wrong hemisphere! You're thinking of Fermilab, the Fermi National Accelerator Laboratory at Batavia, Illinois in the United States. Yes, since physics, including the very highest energy particles is an interest of mine, I enjoyed the pun on “Fermilab”, but that wasn't the only reason…. Some day we'll get around to building that Large Neutrino Collider in the basement. Still, there's some radioactive stuff here.
What's with the ant?
Fourmi is French for “ant” (derived from the Latin formica). So "Fourmilab" is “ant Aphid-ranching ants at Fourmilab laboratory”. As it happens, I've been interested in artificial life since the mid-1970s, long before it became respectable. Ants and ant colonies always seemed to me to be the most interesting models, since they exhibited complex emergent behaviour with simple organisms and a limited number of chemical signals. When Rudy Rucker and I were discussing his “Artificial Life Lab” program, I often urged him to adopt an ant colony model for it. Being a science fiction writer, he had his revenge upon me. The villain of his 1994 novel The Hacker and the Ants was based on me, with the final scene set in the building which now contains the server. But he laughs best who writes last. Amusingly, not long after the publication of The Hacker and the Ants, the largest interconnected network of ant colonies known as of that date was discovered in the Jura mountains, not far from Fourmilab.
But are there actually any robots running rampant at Fourmilab?
K-Team Kephera Mobile Robot Not at the moment. But if you're interested in unleashing autonomous mobile robots yourself at home, check out the Swiss made desktop-scale (50 mm diameter) Kephera and the compatible six-wheeled Koala from K-Team. Both are programmable in GNU C and other languages, equipped with a variety of sensors, and expandable with accessories such as grippers, vision sensors, and radio modems. I am an investor in K-Team.
Why does it take so long to download stuff from your site?
If you're accessing the server from the Western Hemisphere, you may encounter congestion on transatlantic Internet links at peak load periods which can result in slow response. With the improvements in the Internet infrastructure over the last few years, such delays have become increasingly rare.
Where do you get all these crazy ideas?
I read a lot of books…. Starting in January of 2001, I've kept a log of all the books I've read, which you're welcome to peruse. If there's a great book you think I ought to read, there's a form to recommend it.
What's your E-mail address?
I was forced to remove my E-mail address from pages on this site for two reasons, both regrettable. First, any E-mail address on a Web page is quickly “harvested” by spam (unsolicited commercial E-mail) robots and becomes unusable due to the volume of junk mail which arrives. Second, publishing one's E-mail address on pages as frequently visited as many on this site, and as likely to pop out of a search engine when lazy students seek answers to homework problems on the Web, guarantees you'll be bombarded with dozens, if not hundreds, of clueless questions every day. I've published a collection of genuine E-mail which merited my Titanium Cranium Award. Anybody who seriously wants to get in touch should be able to figure out my E-mail address; the rest I don't have the time to deal with. You can always use our notorious feedback form.
What's Your Erdös Number?
Are you in cahoots with and/or
A number of the documents on this site cite, as references, books you're unlikely to find at your local booksellers'. This site, as an associate, allows you to order these books on-line, for delivery anywhere on Earth. We receive a small credit when you buy a book we recommend from Amazon—if you have a Web page, you can do the same for books you mention. Any revenue we receive from Amazon is a tiny fraction of the cost of operating this site; the main reason we link to Amazon is to provide access to books—if you prefer to buy them elsewhere, that's fine. As many of the topics discussed in pages here are rather obscure, it's inevitable some of the books they cite are out of print. I've found an invaluable resource for tracking down and buying such volumes. Their database connects you directly to booksellers worldwide, and allows you to choose a suitable edition, price, and condition before forwarding your order to the bookshop for fulfillment. If you can't find it there, the book you're seeking is in all likelihood extremely rare. We are an affiliate, and earn a modest commission when you order books through their site.

How long have you been on the Web, anyway?
Since December 3rd, 1994. Here is the first hit to the Web site: - - [03/Dec/1994:00:26:26 +0100] "GET / HTTP/1.0" 200 0

What's the matter with kids today?
Play sound Mea culpa! (This audio clip is from episode 605 of South Park, of which season six is now available on DVD.)
I've never seen such quick response from a site in Europe. Who's your Internet Service Provider?
Cablecom Our Internet connectivity is through Cablecom, via a 20 Mbit/sec symmetrical fibre optic link whose installation required digging up the street.
I downloaded a file from your site and my unzip program says it is corrupted. What's going on?
You are probably using Microsoft Internet Explorer, which randomly truncates downloads before they are complete, then serves the incomplete file from its browser cache for subsequent download attempts, all without any warning. See “Corrupted Downloads”: What Is to Be Done? for an explanation of the problem and suggestions on how to avoid it in the future.
What is your Google PageRank™?
The pigeons have pondered deeply on the matter and assigned Fourmilab a PageRank of Google PageRank of
Can I buy/exchange a text/banner link on a page on your site?
No. This is a noncommercial site; there's nothing for sale here, including advertising on our pages. We do participate in associate programs as mentioned above, but these allow us complete control over the links on the site and handle all billing and collection of revenue.
Which Web server do you run?
Apache Apache, of course. It's fast, versatile, secure, and free.
What server hardware do you use?
The site is hosted Fourmilab server farm on a fully-redundant “server farm” mounted in a rack in the Fourmilab Hall of the Servers. The two boxes at the bottom are the Dell PowerEdge 1850 servers which host the site. Each has dual Intel Xeon 3.6 GHz hyper-threaded processors, which gives each server the equivalent of four CPUs. Each has 8 Gb of ECC RAM, dual 146 Gb 10,000 RPM SCSI drives on an embedded RAID controller, and two Gigabit Ethernet interfaces, which are “bonded” into a single logical interface, with each physical interface connected to one of the two 16 port Dell PowerConnect 2616 Gigabit Ethernet switches at the top of the rack. The interface to switch connections of the two servers are crossed with respect to one another. The two switches are connected together and normally forward packets to one another; each is connected to the DMZ port of one of the two redundant firewalls (which aren't in this rack, but in the communications rack upstairs). The network architecture is described in this sporadically updated drawing.

Between the servers and switches are two identical Coyote Point Equalizer 350 load balancers run in primary/backup high availability mode. The top load balancer is connected to the top switch and the bottom load balancer to the bottom switch. Hence, they exchange heartbeats through the interconnected switches, so if one switch goes down, whichever load balancer is connected to the remaining switch will become primary, and since each server has an interface connected to both switches, it will continue to be able to communicate to both servers.

All Fourmilab computers are backed up daily with Bacula onto LTO-3 tapes which are kept forever, with off-site full backups made monthly.

What do you do when the lights go out?
Protected by American Power Conversion Keep on programming, of course! Unscheduled electrical power outages are extremely rare in Switzerland; we've experienced less than an hour total at this site since 1992. Much more worrisome is when things suddenly get too bright. We're located on a plateau at an altitude of about 800 metres above sea level; in the summer we experience frequent violent thunderstorms, with an average of about four nearby lightning strikes per year which get into the power and telephone lines. Circumstances like these require comprehensive power protection, and we've found the Smart-UPS series Uninterruptible Power Sources (UPS) from American Power Conversion do the job superbly. Since installing APC Smart-UPS units on all non-resistive loads in 1994, we have had zero equipment losses due to lightning strikes and zero downtime due to transient power outages. High-wattage equipment insensitive to power outages, such as laser printers and copiers, are protected by APC Line-R voltage regulator and load protection units; they provide the protection of a UPS without the backup battery power in case of outage.