The Blinking Light


3 min read

I was considering buying a new desktop computer, and I thought I had found the ideal model. That is, until I noticed that one little thing was missing—the ­activity light for the hard drive. The manufacturer probably saved a few cents by ­leaving it out, but that little light was of some psychological ­importance to me. How could I possibly buy a computer that was just going to sit there and not give me any indication that it was working?

A very long time ago, not long after the dinosaurs went extinct, I was ­working on modem design. At the Bell System, we had designed modems the way they were supposed to be—big, heavy clunkers with a telephone handset and an embedded rotary dial. They were just what the users needed to connect to their time-shared mainframes. But one day, a competitor came out with a small modem that had an array of LED lamps on the front panel, indicating control signals like clear-to-send as well as data activity. ”What user could possibly care about such things?” we joked among ourselves.

Well, it seemed that people did care about such things. That little company sold a lot of modems, and pretty soon we had ­indicator lights on our modems too. As a consequence, I learned a key principle of design: ­people want blinking lights.

Too many electronic ­gadgets are inert steel boxes with stickers on the ­bottom that say something like ”no user-serviceable parts inside.” Often, you have no idea whether or not the gadget is working. When it doesn’t do something you expect it to do, you stare helplessly at the box. ”Are you alive in there?” you ask plaintively. But such entreaties are a waste of breath. You’d think that the box could at least hum or vibrate to communicate life.

A blinking light makes all the difference—even though you have no idea why it’s blinking the way it is. Over the millennia, humans have evolved a ­subconscious ­ability to recognize and ­categorize moving visual ­patterns, like the flash of tiger fur seen through dense ­foliage. So it is with the ­activity light. I’ve had ­several cable modems go bad, as well as several routers, and in every case I’ve recognized the ­problem by the ­unfamiliar blinking patterns of the ­activity lights. ”Aha,” I say to myself. ”That box is sick.”

Quite often there is no visible activity on my computer screen, but I see the hard-drive light blinking furiously. What is it doing? I wonder. At least the little light tells me that it is alive, though I worry about why it is so busy. At such times I often wish that there were a special key labeled ”What are you doing?” I’ve always found the task manager rather useless for this purpose, and no human being could possibly interpret the gibberish that fills your screen following the dreaded ”blue screen of death.”

Instead of an unintelligible binary dump, my i­magined key would give a simple English explanation: ”I’m busy at the moment reformatting your hard drive,” it might say, ”but I’ll be through in a jiffy.” Or ­perhaps, ”I’m just finishing the installation of a new virus.”

Back when dinosaurs ruled the planet, ­computers had lots of indicator lights, showing the activity on many of the backplane ­signals. When you walked past a computer center, a dynamic light show was ­taking place inside. Tapes spun and everything hummed. ”Wow, look at those things think!” you said to yourself. But now it seems that the only ­indication of life is the roar of air-conditioning.

So the computer I picked out had joined the growing legion of gray boxes devoid of charisma, its only ­outward manifestation of ­personality having been ­sacrificed for a few cents. Maybe I’m the only one who cares about that light now, but I’m not buying that computer. Its designers are probably joking among themselves, ”What user could possibly care about such things?” Well, I’m one who does. For want of a cheap little light, they lost a customer. Hopefully, they’ll put it back in their next model.

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