I trust computers. When I first used A.T.M.'s, nearly 30 years ago, I carefully saved receipts in a folder and matched them with the bank's monthly statement. Now I sometimes stuff the receipts in my wallet, but I almost never look at them again. The only banking error I've encountered in all those years was when a human teller left a final zero off a deposit I had made.

I still pore over credit card statements, but mainly to see whether some person, not some machine, has issued the proper refund credit or made an improper charge. I've sent e-mail messages to the wrong people by mistyping an address or hitting the oh-so-dangerous "Reply All" button, but never because the system routes it where it shouldn't go. When I travel, I assume that the e-ticket I booked through my computer will be valid and that frequent-flier miles will show up in my account.

Yet when I went to my polling place in Washington on Election Day, I waited an extra half-hour in line to cast a paper ballot, instead of using the computerized touch-screen voting machine. Am I irrational? Perhaps, but this would not be the evidence.

A columnist in The Washington Post recently suggested that nostalgia for paper ballots, in today's reliably computerized world, must reflect a Luddite disdain for technology in general or an Oliver Stone-style paranoia about the schemings of the political world.

Not at all. It can also arise from a clear understanding of how computers work - and don't. The more you know about the operations of today's widely trusted commercial computer networks, the more concerned you become about most electronic-voting systems.

The phenomenal reliability of the systems we trust for banking, communication, and everything else rests on two bedrock principles. One is the universal understanding in the technology world that nothing works right the first time, and maybe not the first 50 times.

When I worked briefly on a product design team at Microsoft, I was sobered to learn that fully one-fourth of the company's typical two-year "product cycle time" was devoted to testing. Programmers spend 18 months designing and debugging a system. Then testers spend the next six months finding the problems they missed. It is no secret that even then, the "final" software from Microsoft, or any other company, is far from perfect.

Today's mature systems work as well as they do only because they are exposed to nonstop, high-stakes torture testing. [...] Years ago, bank or airline computers would often be "down" because of unforeseen problems. Now they're mostly "up," because they've had so long for flaws to become exposed.

The second crucial element in making reliable systems is accountability. Users can trust today's systems precisely because they don't have to take them on trust. Some important computer systems run on open-source software, like Linux, in which the code itself can be examined by outsiders.

Virtually all systems provide some sort of confirmation of transactions. You have the slip from the A.T.M., the receipt for your credit card charge, the printout of your e-ticket reservation. If your e-mail message doesn't go through, there is still the copy in your "Sent" folder. This is the technology world's counterpart to the check-and-balance principle in the United States government. The first concept, robust testing, protects against unintended flaws. The second, accountability, guards against purposeful distortions.

Which brings us back to electronic voting. On the available evidence, I don't believe that voting-machine irregularities, or other problems on Election Day, determined who would be the next president. The apparent margins for President Bush were too large, in Ohio and nationwide. But if the race had been any closer, we could not have said for sure that the machines hadn't made the difference. That is because many electronic systems violate the two basic rules of trustworthy computing.

By definition, they have barely been exposed to real-world testing. The kind of thorough workout that Visa's or Google's systems receive every hour happens for voting machines on only a few special days a year. By commercial standards, the systems are necessarily still in "beta version" - theoretically debugged, but not yet vetted by extensive, unpredictable experience - when voters show up to choose a president.

Four years ago, about one-eighth of all votes for president were cast electronically. This year, nearly a third were. How the system would handle that large increase in scale could not have been tested until the presidency was at stake. Worse, most of the electronic systems are not accountable. When I voted this year, I fed my paper ballot through an optical scanner and into a storage box. In a recount, those ballots could have been pulled out and run through the scanner again. If I had used the touch screen, I would have had no tangible evidence that the vote counted or was recountable.

Is that a problem because the chief executive of Diebold, the largest maker of such systems, is a prominent Republican partisan? No. It's a problem because it defies the check-and-balance logic built into every other electronic transaction.

TOTAL TELEVISION
By Mike Hall

Published: November 28, 2004

CBS won the official ratings race during the first full week of the November sweeps, averaging 15 million viewers per prime-time hour, followed by NBC (11.3), ABC (10.4), Fox (7.3), WB (3.8) and UPN (3.7). But what about the 45 million or so other people, on average, who were watching television? Here's another way of looking at the ratings for that week: instead of ranking the broadcast networks, we've ranked the media conglomerates that own them - and nearly every other outlet on your TiVo grid. The easy winner, predictably, was Viacom, owner of CBS and UPN as well as the MTV cable networks. But other high finishers, like Time Warner and Liberty Media, may be names that television viewers don't normally think of while cruising channels. (For each company, we added up the average viewers for all of the networks and cable channels in which it has a controlling interest; joint ventures were divided evenly among the owners. Only networks whose numbers are made public by Nielsen Media Research, and which met the company's minimum reporting standards, were included.)

Viacom
29,762,000

Walt Disney Company
18,656,000

General Electric
17,750,000

Time Warner
12,120,000

News Corporation
10,752,000

Liberty Media
4,144,000

E. W. Scripps
1,705,000

Hearst
1,422,000

Cablevision
1,297,000

Channels included for each company (in order of viewers, highest to lowest):

Viacom: CBS, UPN, Nickelodeon, the N, Spike, MTV, Comedy Central, TV Land, BET, VH1, CMT, Noggin, Showtime, Nicktoons, the Movie Channel, MTV2.

Walt Disney Company: ABC, ESPN, Disney Channel, Lifetime,* A&E,* History,* ABC Family, ESPN2, Lifetime Movie,* SoapNet, Toon Disney, Biography* (*joint ventures with General Electric and Hearst).

General Electric: NBC, USA, Lifetime, A&E, Sci-Fi, History, Pax, Bravo, Lifetime Movie, MSNBC, CNBC, Biography.

Time Warner: WB, TNT, Cartoon, TBS, HBO, Court (joint venture with Liberty Media), CNN, Cinemax, Headline News, Turner South.

News Corporation: Fox, Fox News Channel, FX, Speed Channel, National Geographic Channel.

Liberty Media: Discovery, TLC, Animal Planet, Travel, Game Show, Starz, Encore, Discovery Health, BBC America.

E. W. Scripps: HGTV, Food Network.

Hearst: Lifetime, A&E, History, Lifetime Movie, Biography.

Cablevision: AMC, WE.

Others: Hallmark Cards (Hallmark Channel), 686,000; Comcast (E!, Outdoor Life), 613,000; Gemstar/TV Guide International (TV Guide Channel), 285,000; Tribune (WGN), 272,000; Landmark Communications (Weather Channel), 239,000; Oxygen Media (Oxygen), 238,000.

(More on media consolidation here, here, here, here and here.)