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How big is
a 300 GB hard disk By Jim Sanders, Editor, Orange Bytes, North
Orange County
Computer Club
www.noccc.org
/ editor(at)noccc.org
I recently acquired a 300 GB hard disk for
$110 after
rebates. When I look at that 3.5 inch
hard drive that is one inch high and easily held in my hand, trying to
put those
300 Giga bytes of storage in perspective is a little tough. I thought about the first Z80 CPM system I
built in 1977 from a Cromemco kit that I had to solder together. It used 8 inch floppy disks that held 128,000
Bytes.
The diskettes were easy to damage and it was
a good idea to
keep them in storage boxes. I made some
good money selling the SRW Computer Products plastic storage boxes at a
great
ACP Swap Meet discounted price of $2.00 each. They
were designed to hold 10, but you could get 2 or 3
more in if you
were careful! I wondered how many
floppies that would be, so I punched the numbers into the calculator. 300,000,000,000B/128,000B = 2,343,750
diskettes. I don’t know how to visualize
that, but I did calculate that it would take $468,750.00 worth of those
boxes
to store them all. I then remembered
that the average price at that time was about $3.50 a diskette. Again the calculator, 2,343,750 diskettes x
$3.50 = $8,203,125.00. Wow!
That is a number that I don’t want to think
about if I am talking about a hobby.
Another way to wrap your mind around huge
numbers is to
start small, with something that you can relate to, and work your way
up. Now we know that one byte equals one
character of the alphabet. The common 10
point type has 10 characters per inch. So,
if we have 120 characters/bytes in a row, we have one
foot. There are 5,280 feet in a mile. So
5,280 x
120 gives the number of character or bytes that would be on a mile long
ticket
tape that was being printed with 10 point type, an answer of 633,000
bytes. Compared to the 300 Giga bytes on
the hard
disk, 633,600 bytes is not much. To find
out how much, we need to take the 300,000,000,000 byte capacity of the
hard
disk and divide it by 633,600 bytes in a mile. The
answer to that math problem is the equivalent of
473,485 miles of
ticker tape.
To put that into perspective, let’s take the
circumference
of the earth (nominally 25,000 miles) and divide that into our answer. So, 473,485 / 25,000 = 18.93.
If we could find a big enough roll of ticker
tape, printing all the information on that hard disk would wrap around
the
equator of the earth 18.93 times. That
sounds impressive, but how many people can really visualize that. Besides, I don’t know anyone who has a big
enough ticker tape printer. Another
thought, that ticker tape would be 3,000 miles short of stretching from
the
Earth to the Moon and back.
But let’s try it with regular 8.5 inch x 11
inch paper. Again, standard printing would
be 10 point
type, 10 bytes per inch, and 6 lines per inch. Most
people leave at least a half inch margin all the way
around the
page. So that means each line will be
7.5 inches, or 75 bytes, and there will be 60 lines per page. So each page will use 75 bytes x 60 lines, or
4,500 bytes. First, let’s take 1 of the
300,000 megabytes on the disk and see how many pages that represents. 1,000,000 / 4,500 = 222.2 pages.
We still have 299,999 megabytes left and,
using them, the total number of pages comes out to 66,660,000 pages.
That is also a little hard to imagine, so
let’s see how many
reams of paper that is. Take 66,660,000
pages, divided by 500 sheets per ream = 133,320 reams of paper. Again, a little hard to visualize.
A lot of things have their volume given in
cubic feet. That’s 12 inches x 12 inches x
12 inches or
1,728 cubic inches, or 1 cubic foot. I
measured one case of paper at 11.25x9x17.5 inches, or 1,771 cubic
inches. Let’s be generous and round that
off to one
cubic foot. So at 5,000 sheets, or ten
reams per case, we divide the 133,320 reams that we came up with by 10
to get
13,332 cases, or that many cubic feet of space.
Stipulating that an average house is 1,400
square feet with
eight foot high ceilings, then the average house has 11,200 cubic feet
of
space, ignoring the walls. If you filled
up your house, wall-to-wall, floor-to-ceiling, with cases of printed
paper, you
would still have 2,132 cases left over. If
you are in better shape than I am, there is still room to get one car
in that
two car garage. That’s 10’x20’x9’ = 1,800
cubic feet, so that still leaves us with 332 cases of paper. We could take all of the junk out of the
other half of the garage, lay down a two foot thick layer of paper and
put all
the junk back in on top of it. That’s
how much the 300 Giga byte disk holds! So,
unless you are planning on taking out a home
improvement loan, don’t
buy that 400 Giga byte disk.
There is no restriction against any
non-profit group using
this article as long as it is kept in context with proper credit given
the
author. The Editorial Committee of the
Association of Personal Computer User Groups (APCUG), an international
organization of which this group is a member, brings this article to
you.
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