For those who have trouble keeping bits and bytes, and all the combinations like kilobytes and megabytes and gigabytes, sorted out I found this chart that might help your sort them out just a little bit. For others it may just be interesting.
|bytes||in units||typical meaning|
|1||1 byte or 8 bits||A single keystroke or (non-accented) character; a number from 0 to 255|
|70||70 B||A line of text|
|1,000||1 kB||Half a page of unformatted text; a very short email;
an icon or small button image
|8,000||8 kB||Typical size of an organisation’s logo as you might want it on a web page
(about 200 x 200 pixels PNG or GIF)
|30,000||30 kB||A 5-page word-processor document; a typical HTML web page; traditionally, the maximum recommended size for an image on a web page (maybe 640 x 480 pixels JPEG)|
|100,000||100 kB||The maximum recommended total of all the elements on a single web page, including images and HTML (some authorities say 30 or 40 kB instead)|
|500,000||500 kB||A 5-page word-processor document including a badly-chosen letterhead or logo image;
a reasonable size for a PDF document someone might choose to download;
two 1280×960 JPEG photos from a smartphone, too large for inline use in a web page
|1,000,000||1 MB||1 minute of near-CD quality audio as MP3 or OGG;
A 2048×1536 (4 megapixel) JPEG photo from a smartphone or digital camera, even if blurry because of low light;
the complete comedies and tragedies of Shakespeare when compressed using bzip2
A three-minute MP3 audio at a very high bitrate (256kpbs);
|10,000,000||10 MB||Maximum size of an email that you can expect all recipients to receive|
|25,000,000||25 MB||Maximum size of an email attachment received by GreenNet or GMail (as of 2010);
approximate size of the 26-volume 1911 edition of Encyclopaedia Britannica
|100,000,000||100 MB||Uncompressed TIFF of a single A4 sheet at 600dpi. Note that this may be 100,000 times the size of the equivalent plain text.
The kind of mailbox size or .PST file size at which corruption becomes more likely
|700,000,000||700 MB||Maximum amount of data on one CD-ROM; a two-hour TV programme downloaded from BBC iPlayer|
|4,000,000,000||4 GB||Amount of data on a DVD-ROM or typical new USB flash drive (“memory stick”)
Maximum amount of RAM (working memory) a 32-bit processor can use directly.
|100,000,000,000||100 GB||Typical hard drive size on a computer as of 2009 (doubles about every 2 years)|
|2,000,000,000,000||2 TB||Large external backup hard drive as of 2010|
As a bit of personal perspective, I bought my first hard drive as part of a new IBM clone computer. It was 30 MB and cost $600.00 — just the drive. The whole computer was $2400.00. Therefore the drive storage cost about $20 per megabyte.
My first “big” hard drive was 350 MB and cost $279.00 or a little less than a dollar per mebabyte. My first 1 GB drive cost $400.00, or about 40¢ per megabye. My first 300 GB drive cost $100.00, or about 3/100th of a cent per megabyte.
My most recent (last year) drive purchase, a 1 TB (terabyte) drive, cost $100.00 or, on a per megabyte basis, we might as well call it free. I have been in the market for a 2 TB drive waiting for them to approach the $100.00 price mark but I see I have missed out. They are already as low as $89.00. Today, 4 TB drives are nearly as low as $100.00. Maybe if I wait a little longer they will really be free.
And I still just keep filling them up!
· 1 Bit = Binary Digit
· 8 Bits = 1 Byte
· 1000 Bytes = 1 Kilobyte= 10^3 Bytes
· 1000 Kilobytes = 1 Megabyte= 10^6 Bytes
· 1000 Megabytes = 1 Gigabyte= 10^9 Bytes
· 1000 Gigabytes = 1 Terabyte= 10^12 Bytes
· 1000 Terabytes = 1 Petabyte= 10^15 Bytes
· 1000 Petabytes = 1 Exabyte= 10^18 Bytes
· 1000 Exabytes = 1 Zettabyte= 10^21 Bytes
· 1000 Zettabytes = 1 Yottabyte= 10^24 Bytes
· 1000 Yottabytes = 1 Brontobyte= 10^27 Bytes
· 1000 Brontobytes = 1 Geopbyte= 10^30 Bytes
(Note that it used to be and, accurately, still is: 1024 bytes to 1 kilobyte, 1024 kilobytes to 1 megabyte, etc. but so many people had trouble with the math, or even understanding why you would use 1024, that it has become convention to just use 1000.)
Update: February 16, 2015: I did wait a little and I’m now expecting the delivery of a just-ordered FIVE terabyte drive this week. Price? A tad less than the 4TB drive was when I wrote the original post. Heck, those little thumb drives you can hang on your key ring are now available in capacities exceeding 100 GB! ::sigh::