Source: CompTIA A+ Certification All-in-One Exam Guide, 9th Edition (Exam 220-901 & 220-902) by Mike Meyers (2016)


Computers need some other device that takes copies of programs from the hard drive and then sends them, one line at a time, to the CPU quickly enough to keep up with its demands. Because each line of code is nothing more than a pattern of eight ones and zeros, any device that can store ones and zeros eight-across will do. Devices that in any way hold ones and zeros that the CPU accesses are known generically as memory.

How do you understand that? And why do you need a hyphen there?

  • eight-across means "eight (things) arranged side-by-side" or "arranged in a group of eight, laterally". Stack these 32 boxes up eight-across, then sweep the floor. Feb 16, 2017 at 21:16

1 Answer 1


That's a pretty bad way of explaining what a "byte" is. What they're saying is that computer information is organized into a series of objects that consists of 8 ones and zeros, e.g. "00110011", that we call a "byte" and that's the standard for computation.

That has to be the most roundabout way of explaining how RAM works that I've ever seen, though. All "eight across" means is that there's 8 of them, and that it's valid to look at them like this:




each line being "8 characters across", as a measure of width.

  • Not to mention that it's "eight" chauvinistic. There's nothing magic about the number eight, and most computers doing pass data around in larger chunks, typically 32 or even 64 bits. And a line of code is not necessarily 8 bits. A line of code in a compiled language could be much more, and even in assembly language, there is often an address in addition to the op-code, and some computers have multi-byte op codes.
    – Jay
    Feb 16, 2017 at 19:33
  • I'm sure they get to that in later things, but 1 byte is the smallest piece of information people will typically deal with. It would probably be out of the scope of this course, for example, to try and explain half-adders, busses, and so on to them. Its a good starting point for understanding computer data, especially considering 1byte tends to equal 1 character of text. @Jay
    – mstorkson
    Feb 16, 2017 at 19:47
  • Well, don't want to get into a technical computer discussion here. Yes, on most (all?) computers today, an 8-bit byte is the smallest addressable unit of data. That wasn't always the case, and is not inherent in the nature of computers. It's just a convenient standard we appear to have settled on. The first computer I ever programmed, a PDP-10, had a variable byte size: when you saved or retrieved data, you specified what the byte size was as part of the instruction.
    – Jay
    Feb 16, 2017 at 22:31

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