Check-sum definition of Check-sum in the Free Online Encyclopedia.

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.

(storage, communications)

checksum - 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.

Mentioned in	?		Encyclopedia browser	?		Full browser	?
No references found	check indicator check indicator instruction check ligament check lock check number check nut check observation Check Point check problem check protect symbol check rail check register check routine check row check sample check screen check standard check stop check strip check study check sum check symbol check throat Check Valve check word Check-sum Checkbook checkdigit checked back checker checker plate checkerberry checkerboard regenerator checkered plate Checkers checkerwork checking Checking and Measurement Devices checking floor hinge checking program checking resistance checking routine Checking, Automatic checkline checkmate checkout checkout compiler Checkout Test language checkpoint checkpoint/restart checkroom	check word Check Writer Check Writers Check Writing Check Yearly. See Clearly. Check Your E-Mail Check Your Email Check Your Faulty Spelling Check Your Flanks Check Your Fly Check Your Head Check Your Mail Check Your Settings Check Your Understanding Check's in the Mail Check, Please check-bite check-in check-ins check-list method Check-off dollars Check-off dollars Check-Out Check-Out Check-out counter Check-out counter check-out procedure Check-sum Check-The-Box Check-up Check-up Check-up Check-up check-ups check-ups check-ups check-ups Check/Cash Deposit Module Checka Checka checkable checkable checkable checkable checkable checkable checkage checkback checkbite checkbook checkbook checkbook checkbook journalism checkbooks checkbooks Checkbox Checkbox Checkbox/Radio Input Replacement

Mentioned in

Encyclopedia browser

Full browser

No references found

checksum (redirected from Check-sum)

checksum
(redirected from Check-sum)