aka Système Internationale is a decimal system of measures used nearly everywhere but in the USA. Even in the USA, it is used in medicine, scientific and engineering work and for international trade.
You might wonder why the USA alone sticks with the old complicated Imperial system of measure. The Christian right lobby in the USA hates metric because it was invented by atheists and the worst kind, French during the French revolution.
It is based on standard prefixes. e.g gram (the mass of about a sugar cube of water), kilogram (a 100 grams), milligram (one thousandth of a gram) or metre (a little longer than a yardstick), kilometre (1000 metres, about 5/8 mile), millimetre (one thousandth of a metre). I use both forms of measure on this website, since there are so many American visitors.
Because RAM (Random Access Memory) necessarily comes in modules sizes of even powers of two, the prefix scheme was modified for measuring bytes by even powers of two. Unfortunately, vendors use the binary scheme for measuring RAM capacity but the decimal scheme for measuring hard disk capacity. I suspect they do this primarily to inflate the apparent disk capacity by 7% and because their competitors also do this, rather than as protest against the heretic binary RAM byte measuring prefix convention.
|milligram||1 mg||0.02 gr|
|gram||1 gram||15.43 gr|
|kilogram||1 kg||2.20 lbs|
|millimeter (millimetre)||1 mm||0.04 in|
|centimeter(centimetre)||1 cm||0.39 in|
|meter (metre)||1 metre||3.28 ft|
|kilometer (kilometre)||1 km||0.62 mile|
|milliliter (millilitre)||1 ml||0.20 US teaspoon|
|litre (litre)||1 litre||1.06 US quarts|
|meter/sec (metre/sec)||3.60 km/hr||2.24 mph|
In Canada, the English and French spellings are used interchangeably. The French invented metric, so the French spelling has extra cachet.
You can improve your metric weight intuition by asking the post office to weigh a few objects for you.
|prefix||American English||Standard Decimal
|Power of 10||Byte Measure
Power of 2
There are a series of Greek, Latin, Danish and Spanish prefixes used for specifying large numbers. The prefixes have different meaning when talking about RAM than when talking about disk space.
However, Windows measures hard disk capacity using the binary RAM definition.
For measuring RAM, a gigabyte is a little over a billion bytes, or more precisely, 1024 megabytes = 230 bytes = 1024x1024x1024 bytes = 1,073,741,824 bytes. A byte is approximately one character of information.
A megabyte on disk is precisely a million, namely 109 =1000x1000x1000 = 1,000,000 bytes. For RAM it is a little over a million bytes, namely 220 = 1024 × 1024 = 1,048,576 bytes.
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