checksum

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checksum

(storage, communications)
A computed value which depends on the contents of a block of data and which is transmitted or stored along with the data in order to detect corruption of the data. The receiving system recomputes the checksum based upon the received data and compares this value with the one sent with the data. If the two values are the same, the receiver has some confidence that the data was received correctly.

The checksum may be 8 bits (modulo 256 sum), 16, 32, or some other size. It is computed by summing the bytes or words of the data block ignoring overflow. The checksum may be negated so that the total of the data words plus the checksum is zero.

Internet packets use a 32-bit checksum.

See also digital signature, cyclic redundancy check.

checksum

A value used to ensure data are stored or transmitted without error. It is created by calculating the binary values in a block of data using some algorithm and storing the results with the data. When the data are retrieved from memory or received at the other end of a network, a new checksum is computed and matched against the existing checksum. A non-match indicates an error.

Just as a check digit tests the accuracy of a single number, a checksum tests a block of data. Checksums detect single bit errors and some multiple bit errors, but are not as effective as the CRC method. Checksums are also used by the Sophos antivirus software to determine if a file has changed since the last time it was scanned for a virus. See ECC memory and Sophos.
References in periodicals archive ?
describes how the Library of Congress uses checksums to help maintain and monitor digital materials over time.
When receiving an ASCII message, the two CRC16 checksum bytes are extracted and for the remaining message the CRC16 checksum is calculated.
Checksum Compare Every File-Administrators have the option to compare
1 also includes support for database page checksums to allow detection of database corruption caused by hardware or software failures.
SINView - A console-based utility which can display real-time network statistics including TCP information, UDP counts, ICMP and OSPF information, Ethernet load information, node stats, IP checksums errors as well as most VoIP related statistics and many other useful data stats to help the user better manage the softswitch.
In addition, patches have special checksums to maintain integrity of users backups.
Checksums are generated for each HTML-bound section of that Web page and for the user-defined selection of text, and are then archived.
Users will also be able to compile this information in the form of throughput statistics, latency measurements, valid and invalid packet counts and checksums, bandwidth utilization, error counts, and packet lengths.
As with all Ixia Load Modules, the LMOC48c offers users extreme configuration flexibility, including IP header contents (incrementing, decrementing, or random IP addresses), fixed or algorithmic data patterns, insertable 32-bit, programmable data generators, correct and erroneous checksums, along with full support for ICMP, IGMP, DHCP, TCP, UDP, RIP, BGP, and OSPF.
As with all Ixia Load Modules, the LMOC48c offers users extreme configuration flexibility, including IP header contents (incrementing, decrementing, or random IP addresses); fixed or algorithmic data patterns; insertable 32-bit, programmable data generators; correct and erroneous checksums, along with full support for ICMP, IGMP, DHCP, TCP, UDP, RIP, BGP, and OSPF.
0 compliant Task offloading for IP, TCP and UDP checksums Ingress traffic shaping based on leaky bucket algorithm
As with all Ixia Load Modules, the LM OC12c offers users extreme configuration flexibility, including IP header contents (incrementing, decrementing, or random IP addresses), fixed or algorithmic data patterns, insertable 32-bit, programmable data generators, correct and erroneous checksums, along with full support for ICMP, IGMP, DHCP, TCP, UDP, RIP, and OSPF.