OCR
Optical Character Recognition - Optical Character Recognition technique that, from a process perspective, allows a system computer read and store the text automatically typed, printed or manuscript without having to retype it. A Software OCR enables eg from a scanned text, extract the text portion of the image and edit it into a word processing document.
Byte
English: byte.
More than eight bits. A byte can write 28, Or 256 numbers, from 0 to 255.
The byte is the unit Memory 'scomputer. An alphanumeric character, for example, is encoded by a number with eight bits.
The amount of memory (RAM, mass memory, ROM) Are counted in multiples of bytes.
Originally, and to bring the usual powers of ten (thousand, million ...), the computer chose the multiple 210Which is 1 024, so almost 1 000.
Thus:
1 kilobyte (KB) = 1 024 bytes (210),
1 megabyte (MB) = 1 024 K = 1 048 576 bytes (220),
1 gigabyte (GB) = 1 024 Mb = 1.073 billion bytes (230),
1 terabyte (TB) = 1 024 GB = 1 099.512 billion bytes (240),
1 pétatoctet (Po) = 1 024 To 259 000 = 1 billion bytes (250),
1 exabyte (Eo) = 1 024 Po = 1.15 billion billion bytes (260),
1 zettabyte (Zo) = 1 024 Eo = 1 180 billion billion bytes (270),
1 yottabyte (Yo) = 1 024 Zo = 1.208 million billion billion bytes (280).
To simplify and use the usual meanings of the prefixes kilo, mega, giga ... but also for marketing considerations, manufacturers of hard drivesAnd producers DVDHave become accustomed to round to decimal powers.
Thus, a gigabyte DVD actually contains one billion bytes. The 4.7GB announced therefore represent only 4 700 000 000 bytes. The difference is moreover to burning large files. The file size advertised by a computer (eg Windows) is it, counted in units of computer and a total of 4.7 GB will not hold onto a DVD (you have to count with the space lost by formatting information from a DVD) .
For hard drives, the definition varies. The capacity is sometimes indicated in GB computer and sometimes in decimal GB.
A note in English must be wary of the possible confusion between bit (bit) and byte (byte).
kb, Mb, Gb ... mean kilobit, megabit, gigabit ... while as KB, MB, GB ... mean kilobyte, megabyte, gigabyte...
ODA
Standard representation of document structure office.
The ODA standard is a standard for theISO (IS 8613) and CCITT (T.401 recommendations to T.408).
OFDM
Technology modulation of dividing the signal on a large number of orthogonal subcarriers modulated individually low flow. Besides spectral efficiency very close to the optimum, this technique provides excellent resistance fading (fading frequencies).
OFDM is used for television Digital terrestrial mode fixed (DVB-T) or mobile (DVB-H), Digital radio (DAB, DRM), But also for wireless networks that use 802.11a, 802.11g (WiFi) And 802.16 (WiMax) In particular.
|
