A reader asks: “Is it illegal to ride an electric bike on a bike trail?”

Local ordinances vary, but you usually can use common sense. If the e-bike is designed to behave like a regular, muscle-powered bike, there’s usually no problem. For example, if it’s an electric assist bike — ie one where you still pedal some or most of the time — and if the bike is ridden at…

A reader asks: “Why is RAM called random access memory?”

Recall that early computers used tape as memory — paper tape at first and later, magnetic tape. Tape-based memory is serial: If you want a byte of memory in the middle of the tape, you have to start at one end of the tape and spool through to the location you want. That’s clumsy and…

A reader asks: “How do you put your face on another picture using MS Paint?”

With great difficulty. MS-Paint is a very simple tool. You can cut and paste, but you cannot blend edges or do any other adjustments to make the final image look like anything other than what it is — a crude cut and paste. Windows 10 has Paint 3D, which offers a “smart select” tool to…

A reader asks: “How can I recover Android data after a factory reset if it wasn’t backed up?”

That’s a terrible feeling, isn’t it, when your data’s gone — maybe forever! Ugh. But it may not be gone, or at least, not all of it. Google, or your phone maker, may have provided at least some automatic backup services for you. Some third-party apps may have likewise saved some or all of your…

A reader asks: “Why are the squirrels in Boston Common so fat?”

They are exceedingly well fed. Boston hosts something around 20 million visitors each year. About 3 million of them walk the Freedom Trail, which starts at Boston Common. There also are many public events in the Common — concerts, fireworks, festivals, political gatherings, celebrations, etc. — throughout the year, which attract both visitors and residents….

A reader* asks: “Do people drive a lot worse in the rain in Boston, MA?”

Yes, of course. Accident rates in Boston go up in the rain — just as they do in every other location on the planet. I’m not sure what else you’d expect when roads get slippery and visibility goes down! I’m guessing that what you’re really getting at is the poor reputation of Boston drivers; and…

A reader asks: “I dropped my hard drive. How could I possibly fix it?”

That depends on exactly what broke. Pick up the drive and gently shake it. Is there loose stuff inside the housing? If you hear pieces rattling around, you may have broken one or more of the disc platters (disc platters are often made of glass, coated with a metallic layer). And if platters are broken,…

A reader asks: “How can I reduce laptop noise?”

Laptop noise usually comes from four components: the cooling fans; any spinning-media data-storage device (e.g. hard drive or DVD); the keyboard; and the speakers. We’ll discuss those in reverse order, and immediately discount the speakers: I seriously doubt that’s the kind of noise you were referring to! You can just turn down the volume, or…

A reader asks: “How much does charging a mobile phone cost?”

Not much. In fact, probably less than a penny! You can roughly guesstimate it for yourself this way: Note that electricity is usually sold by the kiloWatt hour (kWh) — 1000 Watts delivered for one hour. If you know the Wattage of your phone charger, and how long it runs, you can very easily calculate…

A reader* asks: “Will upgrading my RAM from 3000 MHz to 3200 MHz yield a performance gain?”

Meh. You’ll either see no gain at all; or so little that you won’t notice. Here’s why: The circuits that RAM plugs into are controlled by a clock that sets the pacing for all memory-related operations in that part of the PC. In the vast majority of PCs, the RAM clock speed is set at…