Welcome to Exploring Computing.
Today's video is bits, bytes, and binary part 1,
or It's All About Zero and One.
Computers use the binary number system.
So let's take a look at what binary numbers look like.
We'll begin by comparing decimal numbers, which
are the numbers we're used to to binary numbers.
Decimal numbers are based on the decimal number
system, which is the number system that you are used to.
In the decimal number system, there
are 10 different digits, 0 through 9.
All the numbers that you're used to seeing
contain these 10 different digits.
We also sometimes refer to this number system as base 10.
In contrast, the computer uses a binary number system.
In the binary number system, there
are only two digits, 0 and 1.
Here are some examples of the different types
of numbers that you can make with the binary number system.
We'll take a look at another video on exactly how these work
and what they might mean.
But for now, just realize that all numbers
in the binary number system consist of only two digits, 0
and 1.
And because of this, because there are only two digits,
we sometimes refer to numbers using this number system
as being base 2.
What I want to look at next is why computers
use the binary number system.
If we were to open up the computer
and look at computer memory, what we would discover
is that computer memories actually
consists of a whole bunch of different individual electronic
switches.
We can think of these electronic switches
as being not that different than your light switch.
And just as a light switch on the wall
can either be on or off, our switches inside the computer
can be on or off.
When the switch is off, we think of that
as representing the number 0.
And when the switch is on, we think
of that as representing a 1.
So each of our switches corresponds to a single digit.
And since these digits can only be 0 or 1,
they're binary digits.
And we shorten binary digit to bit.
So when you hear somebody talking
about a bit, what they're talking about is a 0 or 1,
or the memory inside the computer,
which is being used to store that 0 or 1.
Now we can't really do a whole lot with a single bit,
so we combine the bits together into groups.
And the main grouping for bits is
the set of eight bits, which is referred to as a byte.
The byte is a primary measure of computer storage.
While I've been describing what happens
inside the main computer memory, all computer data
is ultimately stored as bits and bytes.
So there are a variety of different mediums
that we use to store digital information.
And in each case, that digital media
needs to be set up to store zeros and ones or bits
and bytes.
So an SSD drive, which is what's inside most of your laptops,
stores information basically using
electronic switches very similar to the ones we've
described here.
However, if you've got a hard disk,
if you open up the hard disk, what you're going to discover
is that there are individual sections on the disk itself
that are magnetically polarized.
And depending on the polarity, if the polarity is
in one direction, it'll be considered a 0.
If the polarity's in the opposite direction,
it will be considered a 1.
If we take a close look at a CD, a DVD, or Blu-ray,
what we're going to discover is that the disk consists
of a number of different sections, which are either what
we refer to as pits or lands.
Depending upon whether there's a pit in that section of the disk
or a land in the section of the disk,
ultimately what we're representing with these pits
and lands is zeros and ones.
So again, ultimately all information
used by the computer is going to be stored in these zeros
and ones or these bits.
And they'll be organized into groups of eight called bytes.
While our first video has been rather short,
the other videos in this lecture are much longer.
In the next video, we're going to take a look at how
binary numbers actually work.