Why You Boot Your Computer (and Other Strange Terms)

byphil1944

8.6K followers

7 years ago

This will probably be of no interest to you unless, like me, you're the sort of person who likes to know the origin of things.

But to be honest, I've set myself a goal this weekend of writing and scheduling a week's worth of posts to two of my websites on WA and writing a blog post here is one way of postponing that job. Anyone else relate to that?

Next, I'm going to watch the last episode of Game of Thrones Season 7, as a final catch-up before the final Season 8 is released on April 14.

Then I will have run out of excuses and be forced to start writing my six posts.

Why Do We Boot Our Computers?

Where was I? Oh yes, why do we boot our computers?

I started working with computers pretty much when computers themselves started, at least commercially.

Way back in 1965!

When you think about it, it's pretty amazing that a computer can start up at all.

After all, it's totally run by software.

With no software running, it's just a machine soaking up electricity. But it takes software to get it going. But how can software get it going when there's no software running? Sort of a Catch-22.

Enter the Bootstrap Routine.

This was a small set of computer instructions, written in machine language so no translation was necessary and stored on an external device, originally punched cards or perforated paper tape. The cards or tape were read by a card or tape reader directly into memory address zero. The bootstrap routine contained instructions to read a more complex set of instructions, originally from magnetic tape and later from a hard disk drive. The final instruction in the bootstrap routine was to tell the computer to execute the instructions starting in memory address zero. This loaded the more complex set of instructions which in turn loaded the operating system and the computer was then up and running.

The analogy to this was pulling yourself up by your own bootstraps.

So starting a computer was known as "bootstrapping" it.

By the time the IBM PC was launched in 1981, this had been abbreviated to "booting" it.

Modern Computers

Modern computers start up in exactly the same way. The only difference is that the bootstrap routine is stored on a ROM (Read Only Memory) chip on the motherboard and the hardware forces it to be read as part of the hardware startup process. A ROM keeps what's stored on it when the power is off, whereas RAM (Random Access Memory) loses it.

Other Terms

BIT stands for Binary Digit. It has a value of 0 or 1. Used because a memory address can be ON (1) or OFF (0).

A BYTE is 8 bits and so can take a value from 00000000 to 11111111. The latter in decimal has the value 255, so a byte has 256 possible values. Each of these is used to represent a lower case letter, an upper case letter, a decimal number or a special character such as a comma or asterisk.

Lots of other stuff, but I suspect most of you will have lost interest by now.

But I can remember why Windows almost never made it, if you want to know more history from someone who was there :-)