An important component of enabling information integrity is sustaining data and task validity. The purpose of an IT hardware validity check is to assist in ensuring that infrastructure processing activities are appropriate actions. By definition, an appropriate action is one that conforms to a set of authorized rules that are considered to be correct or reasonable.

Determination of the validity of an IT hardware action is something a redundancy check is unable to perform. However, in conjunction with redundancy checks, validity checks provide considerable certainty that hardware processing and transfer of datum will be complete, accurate and creditable.

Information validity implies data elements represent real conditions, rules or relationships rather than physical object characteristics. IT hardware validity checks are preventive and/or detective control measures that should be implemented to ensure appropriate data processing. There are three primary types of IT hardware validity checks: operation validity, data validity, and address validity.

Validity Checking of Operation Codes within the Central Processing Unit (CPU)

Each computer has a recognizable instruction set (e.g. Reduced Instruction Set Computing (RISC)) with a designated code for each instruction, such as addition, subtraction, multiplication, and division. The operation validity check will signal an error condition if, during execution, a program attempts to process an invalid instruction.

Validity Checking of Datum Passed to Peripheral Devices

A data validity check compares characters or fields that are written or read with a set of all valid characters or fields. It is particularly useful technique with peripheral devices such as printers. For example, a printer may be limited to a certain number of characters. Consequently, if there where sixty-four characters associated with a print drum the data validity check would accept data containing any of the sixty-four characters as valid, yet would reject data representing other characters considered invalid.

Validity Checking of Storage Location Addresses

IT memory has designated storage addresses that can be accessed. CPUs utilize control units to keep track of addresses associated with the IT configuration. The address validity check compares the memory address requested with the list of valid addresses to detect an invalid request.