Lenovo F410 Benutzerhandbuch Seite 25

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7. Why the capacity shown on the computer is different from the hard disk
specifications?
Answer: The hard diskmanufacturers mark the storage capacity of the hard
diskbased on the decimal system, so the capacity unit of the hard disk is:
1MB=1000×1000 bytes=1 million bytes (the decimal system);
1GB=1000×1000×1000 bytes=1 billion bytes (the decimal system);
1TB=1000×1000×1000×1000 bytes=1000 billion bytes (the decimal system).
Inside the computer, the calculation is based on the binary system. For the
conversion purpose, similar KB, MB, GB and TB are taken as the units of
measurement respectively, hence:
1KB=1024 bytes;
1MB=1024×1024 bytes=1048576 bytes, approximately equal to 1.05MB (the
decimal system);
1GB=1024×1024×1024 bytes=1073741824 bytes, approximately equal to
1.07GB (the decimal system);
1TB=1024×1024×1024×1024 bytes=1099511627776 bytes, approximately equal
to 1.1TB (the decimal system).
Since the calculation methods above are different, the nominal hard diskcapacity of
the product is therefore also different from that as shown inside the computer. For
example, the hard disk with the nominal 40GB (the decimal system) capacity, if
converted as inside the computer, it is approximately 37.25 GB (the binary system).
Due to the diversity of calculation methods, the features of storage media and file
format management also require a certain amount of storage space, thus leading to
actual available capacity of the product being lower than the hard disk specification.
Lenovo Portable Hard Drive User's Guide
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