FileSlinger™ Backup Reminder 9-3-04: Bits, Bytes, and Backups before SP2

I’m about to make some very major backups indeed, because I’m going to reinstall my computer from the ground up in order to put Windows XP Service Pack 2 on. (There are some 200+ programs known to function incorrectly after the installation of SP 2, mostly those which download automatic updates from the internet.)

For those of you using XP, you may not need to do a complete reinstall in order to be able to cope with SP 2, but it’s certainly a good idea to make a complete drive mirror before doing so, just in case it causes some serious problems with your computer.

And whatever operating system you use, it’s important to keep your data (those word-processing, database, spreadsheet, photo, and music files) backed up regularly.

Today’s topic is numbers, and it’s not strictly about backup. Numbers can be distinctly confusing when it comes to computers, depending on what you’re using them to refer to. And in my editorial tidying-up zeal last week, I converted a lot of lower-case ‘b’s to upper-case ‘B’s without realizing the consequences.

A lower-case ‘b’ is a bit.

An upper-case ‘B’ is a byte.

A byte is 8 bits. (Your extra credit question: what is a nibble?)

Hence I was off by a factor of 8 in most of the numbers I reported.

Part of the problem was that we don’t use bits at all anymore when we talk about storage capacity, e.g. the size of a hard drive. In fact, we rarely even use bytes, or even kilobytes (KB, or 1024 bytes, though it’s usually considered 1000 bytes for convenience). Removable storage capacity is generally measured in megabytes (MB, 1000 KB or 1,000,000 bytes) and hard drives are usually measured in gigabytes (GB, 1000 MB or 1,000,000,000 [billion] bytes). If you are the Ur-Guru, then your hard drive size is measured in terabytes (TB 1,000,000,000,000 [trillion] bytes—numbers too big for the rational brain to handle but which Bill Gates’ net worth probably approximates).

In Greek, mega means “big,” giga means “giant,” and tera means “monstrous.” Personally, I think that’s right on target.

But data transfer rates are measured in multiples of bits. And the “speed” of a network is its data transfer rate—the number of bits per second that can cross the cables or airwaves to their destination. Most home networks have a 100 Kbps (kilobits-per-second) rate. The Ur-Guru’s network has a 1 Mbps (megabit-per-second) rate—so it’s 10 times faster than mine, and it’s likewise more than twice as fast as USB 2 or firewire.

That’s probably more detail than anyone wanted to know, but I wanted to get it correct so that I’m not misinforming you. I won’t get into why a kilobyte is 1024 bytes. It has to do with operating in the binary (base two) system instead of the decimal system, on which subject I commend to you Tom Lehrer’s song “New Math.”

My computer will be away for the weekend, but my mail server will still be operating, so send in any questions, comments, or SP2 horror stories you might have.