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September 3, 2001 First Draft
November 19, 2002 Reviewed no changes made
August 11, 2004 Corrected the 2n table based on feedback from Rutger Bijlsma
While trying to explain the concept of bit, byte, kilobyte, megabyte, gigabyte to my wife, it dawned on me that I didn't have all the facts together. So for future generations who are running 3D first person shooter games with full screen anti-aliasing at 50 frames a second on their 20Ghz Itanium 5 systems, this is a little history lesson on the magnitude of computing power.
| Term |
Abbreviation |
Mathematical |
Actual Size |
Common Size |
Computing Era |
Examples |
|
|
| bit |
no abbrev. |
21 |
0 or 1 |
0 or 1 |
1854 |
on / off
true / false |
|
History:
George Boole creates Boolean algebra. This described a way of thinking and
is the fundamental rule behind the logic of computers. To this day, many
languages implement a bool or boolean variable which has the
value true or false. The concept of true and false drive programming
paradigms to this day. However, it is not until the 1930's that the first
analog computers are built. In 1940's, the first the ENIAC was made, which
is considered to be the first modern computer. The definition of a bit is
a binary digit
Other:
Telecommunications speed are still measured in bits, the standard 56
Kbps analog modem speed is actually 56,000 bits per second. Technically
this resolves to 7,000 bytes per second, which is approximately 6.8KB per
second. However, full transmission rates are very rare.
10/100 ethernet also uses the bit for its basis. 10Base-T ethernet and 100Base-T ethernet (also called fast ethernet) allow for transfer speeds of up to 100Mbps (Note: Mbps is mega bits per second or 100,000,000 bits per second and not the 2n model.)
Encryption algorithms still use bit identification to describe the key system.
128bit encryption, currently thought to be the best, supercedes 40bit and
56bit encryption systems. One can only look at the 2n model to
deduce that 256bit encryption will soon follow.
|
| byte |
no abbrev. |
28 |
8 bits |
8 bits |
1940's |
a character - 'a'
a symbol - '@'
a value - '4' |
|
History:
With the advent of computers, a standard had to be derived that would allow for the representation of entire alphabet, including upper and lower case letters. 8bit bytes allowed for representation of 256 characters, numbers and symbols, as well as a range of numbers from 0 to 255 unsigned or signed (ie +/-) from -127 to +127. Although many current languages (c, c++, java, perl etc) represent integer numbers as 4 bytes in memory allowing for a much larger number.
|
| kilobyte |
KB |
23 |
1024 bytes |
1024 bytes |
1960's |
This document is about 9 kilobytes |
|
History:
Today, this is one of the smallest commonly used units of measurement used
in computing, beyond the eternal bit. Common for referring to hardware
in the late 1980's when IBM Compatible computers shipped typically with
640KB of RAM (system memory). Also used to describe floppy disk size (360Kb,
720Kb)in the late 70's and early 80's the kilobyte was the most common storage
size you would hear.
Examples:
A 1.4 Megapixel camera image is about 500KB
Web graphics are usually under 20KB
A 1 page word processor document is usually about 50KB
Other:
1Kb = 1024 bytes
1Kb = 8192 bits
|
| megabyte |
MB |
220 |
1,048,576 bytes |
1,000,000 bytes |
1990's |
Computer Memory |
|
History:
Early hard drives in the 1980's (also called hard disk drives hence the
HDD abbreviation) were commonly 1 - 2 MB. In addition to a larger storage
capacity than floppy drives, hard disks were considerably faster. This allowed
the computer to keep programs on the hard disk and allowed the operator
to use programs without swapping disks to access different functions. Some
early computers in the 1980's were available with 1MB of memory. However,
until the introduction of the Intel 386 (or i386) memory was still referred
to in kilobytes. The i386 and i486 based machines commonly had between 2MB
- 4MB of memory. Also with increased file sized of audio and image data,
portable storage solutions such as Zip Disks and Super Disks were released
with capacities from 100MB to 120MB. An attempt at a second generation floppy
drive included a 2.44MB floppy based on the 3.5" floppy drive still found
in machines today, the drive was unsuccessful.
Examples:
MP3 Audio files are typically 3MB - 5MB
CD-ROM Discs hold approximately 650MB of data
Currently computers typically ship with 64MB - 256MB RAM
A Professional Digital Camera may take images with file sizes as high as 18MB
Windows 3.1 used 10MB of disk space
Other:
1Mb = 1,024 kilobytes
1Mb = 1,048,576 bytes
1Mb = 8,388,608 bits
Today a 56Kbps analog modem, at maximum speed would take around 3 minutes to download a 1MB file.
Broadband solutions such as cable modems and DSL (Digital Subscriber Lines) allow for faster transfers of data at rates of 64Kbps-1.5Mbps (note: Mbps for Mega bits per second) depending on service level. A common speed for these services is 128kbps - 256kbps.
|
| gigabyte |
GB |
230 |
1,073,741,824 bytes |
1,000,000,000 bytes |
late 1990's |
Computer Hard Disks |
|
History:
In the late 1990's 1GB and 2GB hard disks were common in computers. By 2000, 15GB Hard Disks were becoming affordable as well as the increased sale of scanners and digital cameras. People started using their computers for image manipulation and storage on a much larger level. Another driving factor for individuals to get larger hard disk capacity was the wide spread acceptance of the MP3 Audio format, widespread use of broadband internet, and peer to peer file sharing networks; people began building collections of MP3's.
Examples:
DVD Discs store 4.7GB of data
Currently computers typically ship with 20GB - 80GB HDD
Web hosting providers limit shared hosting solutions from 5GB - 25GB of data transfer per month
Other:
1GB = 1,024 megabytes
1GB = 1,048,576 kilobytes
1GB = 1,073,741,824 bytes
1GB = 8,589,934,592 bits
Use of the term gigabit was used in 1999/2000 for ethernet to describe new line speeds.
|
| terabyte |
TB |
240 |
1,099,511,627,776 bytes |
1,000,000,000,000 bytes |
|
Massive Storage Systems |
|
History:
There isn't much history behind the terabyte yet. Terabytes of storage are
typically set up in what's known as a Storage Area Network or a SAN.
Other:
1TB = 1,024 gigabytes
1TB = 1,048,576 megabytes
1TB = 1,073,741,824 kilobytes
1TB = 1,099,511,627,776 bytes
1TB = 8,796,093,022,208 bits
|
| petabyte |
PB |
250 |
1,125,899,906,842,624 bytes |
1,000,000,000,000,000 bytes |
|
|
|
History:
There is no history to date about actual use of the petabyte. Be patient
we will get there.
Other:
|
| 2n |
Number of Values |
Common Name |
| 21 |
2 |
Bit |
| 22 |
4 |
| 23 |
8 |
| 24 |
16 |
| 25 |
32 |
| 26 |
64 |
| 27 |
128 |
| 28 |
256 |
Byte |
| 29 |
512 |
| 210 |
1,024 |
Kilobit |
| 211 |
2,048 |
| 212 |
4,096 |
| 213 |
8,192 |
Kilobyte |
| 214 |
16,384 |
| 215 |
32,768 |
| 216 |
65,563 |
| 217 |
131,072 |
| 218 |
262,144 |
| 219 |
524,288 |
| 220 |
1,048,576 |
1 Megabit |
| 221 |
2,097,152 |
| 222 |
4,194,304 |
| 223 |
8,388,608 |
1 Megabyte |
| 224 |
16,777,216 |
| 225 |
33,554,432 |
| 226 |
67,108,864 |
| 227 |
134,217,728 |
| 228 |
268,435,456 |
| 229 |
536,870,912 |
| 230 |
1,073,741,824 |
1 Gigabit |
| 231 |
2,147,483,648 |
| 232 |
4,294,967,296 |
| 233 |
8,589,934,592 |
1 Gigabyte |
| 234 |
17,179,869,184 |
| 235 |
34,359,738,368 |
| 236 |
68,719,476,736 |
| 237 |
137,438,953,472 |
| 238 |
274,877,906,944 |
| 239 |
549,755,813,888 |
| 240 |
1,099,511,627,776 |
1 Terabit |
| 250 |
1,125,899,906,842,624 |
1 Petabit |
Penn Printout: Abacus to ENIAC: highlights in the history of computing http://www.upenn.edu/computing/printout/archive/v12/4/abacus.html (March 1996 Volume 12:4)
For more information on this and other topics, you can find resources here:
Google Search: binary adding machine
Google Search: history of computers
Google Search: eniac computer
Historic Computer Images: also includes a tree diagram of computer development
Copyright (C) 2000-2010, Erik Giberti (AF-Design), All rights reserved.
Program as used in this license may refer to entire software packages, code snippets and binary image or visual information.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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