ⓘ Header, computing. In information technology, header refers to supplemental data placed at the beginning of a block of data being stored or transmitted. In data ..


ⓘ Header (computing)

In information technology, header refers to supplemental data placed at the beginning of a block of data being stored or transmitted. In data transmission, the data following the header is sometimes called the payload or body.

It is vital that header composition follows a clear and unambiguous specification or format, to allow for parsing.


1. Examples

  • E-mail header: The text body is preceded by header lines indicating sender, recipient, subject, sending time stamp, receiving time stamps of all intermediate and the final mail transfer agents, and much more.

Similar headers are used in Usenet NNTP messages, and HTTP headers.

  • In archive file formats, the file header might serve as a fingerprint or signature to identify the specific file format and corresponding software utility.
  • In some programming languages for example C and C++ the functions are declared in header files.
  • In graphics file formats, the header might give information about an images size, resolution, number of colors, and the like.
  • In data packets sent by wireless communication, and in sectors of data stored on magnetic media, typically the header begins with a syncword to allow the receiver to adapt to analog amplitude and speed variations and for frame synchronization.
  • In a data packet sent via the Internet, the data payload are preceded by header information such as the senders and the recipients IP addresses, the protocol governing the format of the payload and several other formats. The headers format is specified in the Internet Protocol.
  • Header may refer to: Header computing supplemental data at the beginning of a data block E - mail header HTTP header Header file, a text file used in
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  • When computing the checksum, again a pseudo header is used that mimics the real IPv6 header The source address is the one in the IPv6 header The destination
  • complement of the one s complement sum of all 16 - bit words in the header For purposes of computing the checksum, the value of the checksum field is zero. If
  • MMLite Microsoft Invisible Computing Microsoft. 2004. Retrieved 28 June 2012. aif ldr.c Microsoft Invisible Computing Microsoft. 2004. Retrieved
  • refer to: From, a preposition From SQL and From: email message header in computing FromSoftware, a Japanese video game company Full range of motion
  • In computing Internet Protocol Security IPsec is a secure network protocol suite that authenticates and encrypts the packets of data to provide secure
  • events in the history of computing from 1950 to 1979. For narratives explaining the overall developments, see the History of computing Information revolution
  • are used to specify the ingress and egress RBridges in the TRILL header The TRILL header consists of six octets: the first two octets include a six bit
  • In electronics and particularly computing a jumper is a short length of conductor used to close, open or bypass part of an electronic circuit. They are
  • In computing tar is a computer software utility for collecting many files into one archive file, often referred to as a tarball, for distribution or
  • first header field in an IP packet is the four - bit version field. For IPv4, this is always equal to 4. Internet Header Length IHL The IPv4 header is variable
  • of work to compute but the proof can be verified efficiently. For email uses, a textual encoding of a hashcash stamp is added to the header of an email