What do giga and tera actually count?
Giga, tera. You always hear these when talking about storage. But what are they all counting, really? Starting from a single bit, let's uncover what these units are.
One bit is just two things
The single bit we've seen so far.
It shows just 0 or 1,
on or off,
only two things.
Yes or no works,
but with only that
it's hard to hold a number or a letter.
Try turning it on and off.
What one bit holds.
So, as we saw last time,
we have to bundle several bits.
But how many per bundle is good?
Too few and it's not enough,
too many and it's wasteful.
Here a clever number shows up.
Bundle eight and you get 256 things
Computers decided to bundle bits
eight at a time.
With eight, the number of things you can show
comes to 256.
That's more than enough
to hold English letters, digits, symbols.
This bundle of eight
is called one byte.
Toggle 8 bits (one byte).
Why eight, you ask?
Because it's just right.
Enough to hold one character,
and clean to handle.
So the byte became
the basic unit
with which computers handle information.
One byte fits one character
Remember from lesson 3?
Each letter has a number,
and that number becomes 0s and 1s.
One English letter
fits in exactly one byte.
Pick a letter
and you can watch it turn
into eight 0s and 1s.
One character = one byte.
One character, one byte.
So a word written in English is
a few bytes,
this sentence is dozens of bytes.
Storage size
was counted like this all along.
The amount handled at once, the word
If the byte is the basic unit of information,
the word is the amount a CPU
handles at once.
Like a person eating one spoonful at a time,
the CPU too takes a fixed size
in one bite.
Today's computers usually handle
eight bytes, that is 64 bits,
in one bite.
The amount taken in one bite (word).
The phrase "64-bit computer,"
you've heard it, right?
That's exactly what it means.
It can handle 64 0s and 1s
at once.
The bigger the bite,
the more work it does, and faster.
Kilo, mega, giga, tera
Now let's go to big units.
When about 1,000 bytes gather,
that's one kilobyte (KB),
and about 1,000 of those
is one megabyte (MB).
It climbs by a thousand each step.
Giga, tera too
were all words for counting bytes.
Units climbing by a thousand.
So a "512-gig laptop"
means it can hold
about 500 billion 0s and 1s.
What started with a single switch in lesson 1
has come all the way here.
Giga and tera too,
were words for counting switches in the end.