The Apple Macintosh Plus is a distant ancestor of today’s sleek laptops despite being only about a quarter-century old. (Photo: Raneko)

Cambridge Day is part of a project called Voices of MainStreet — a weekly, nationwide Q&A in which editors at the money and lifestyle site MainStreet.com ask questions and bloggers answer them. For this entry, I was asked about technology.

As the keeper of my family photos and videos, calendar, address book, music, tax records, correspondence and writing, as my primary DVD player and news source, as the way I keep in touch and how I do my work, my laptop is more or less my life in 5.6 pounds of aluminum, glass and plastic.

I’m aware of what a first-world thing this is to say, but the combination of personal meaning, professional significance and investment makes it literally the most valuable object in my life.

And since I lug the thing around with me pretty much everywhere, and use it almost constantly, I’m reminded of this nearly every day. No iPad or iPhone can do what my laptop does — yet — and I can’t reconcile spending money on other stuff, from the tiniest e-reader to the biggest flat-screen television, when my laptop more or less does it all already.

It’s simultaneously a wonder and the logical culmination of the path I shared with my brother in the early 1990s, when he gave me a 16-pound Apple Portable. (It had a 10-inch screen in a bulky body shaped like a late-model electric typewriter, making it technically portable. The Environmental Protection Agency has also deemed the Rolls-Royce Phantom Coupe a compact car.) It was the same path my father set me on on 1984, when he brought home one of the first Macintosh computers. Before that we’d had Apples. And before that other computers — cobbled-together things with names lost to a history so shrouded in geekiness I can barely bring myself to look in its direction.

But permit me to share three remembered artifacts of technology that will seem absurd, or like the fake answers on a “Bluff the Listener” segment of NPR’s “Wait Wait … Don’t Tell Me.”

• The storage medium for programs or files on those ancient, nameless, pre-Apple II computers? It was audio cassette, the same magnetic audiotape cassettes on which one might record some Melanie or Harry Chapin from a vinyl LP, 30 minutes per side, except in this case the ubiquitous portable Panasonic tape recorder was plugged in — somehow — to a kit-built computer. Inevitably, the tape recorder misbehaved and the tapes unspooled. Really.
• My first watch was a digital “Star Wars” model, probably a 1977 version by Texas Instruments with a readout of red LEDs surrounded by a metallic oval. The watch came with a sheet of stickers showing several different scenes from the movie that could be applied atop that oval. I remember excitedly applying the first one — poorly — and promptly losing the rest. It is astonishing to me this can be bought, used but working, for only $50. But no stickers. Maybe everyone lost them?
• We had video game systems in the 1970s too, which we connected to the television. Nothing too astonishing there. But our Pong or Tank games on the system I remember my siblings and I using were just white blocks of light on a black background, with the white blocks of light behaving differently depending which game we selected. The colorful graphics of tennis courts or battlefields, and I swear I am not making this up, were printed on sheets of acetate you stuck to your television screen with tape.

Have I blown your mind? Are you, um, ROFLing? Or are you just kissing your sleek 15-inch laptop, with its speakers, DVD burner, backlit keyboard and massive memory and storage, as I might, in appreciation of how far technology has come in three decades?