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Chapter 10
Processing Integrity and Availability
| Term | Definition |
|---|---|
| Data Entry Checks (Input Controls) | Field Check, Sign Check, Limit Check, Range Check, Size check, Completeness check, Validity check, Reasonableness check, Check digit verification, Prompting, Close-loop verification |
| Field check | Characters in a field are the proper type. E.g. Text, integer, date, etc. |
| Sign check | Proper arithmetic sign |
| Limit check | Input checked against fixed value. Ex. Proper payroll hours worked must be equal to 40 hours |
| Range check | Input within low/high range value. |
| Size check | Input fit within field |
| Completeness check | Has all required data been entered. Ex. shipping address been entered |
| Validity check | Input compared with master data to confirm existence. Ex. Sales order with product ID # matches DB product ID # |
| Reasonableness check | Logical comparisons. Ex. OT hours should be 0 if not worked over 40 hours. |
| Check digit verification | computed from input value to catch typo errors |
| Prompting | Input requested by system |
| Close-loop verification | Uses input data to retrieve and display related data. Ex A/C # entered and system displays account name. |
| Batch Input Controls | Batch Processing: Input multiple source docs at once in a group Batch Totals: Compare input totals to output totals *Financial - Sums a field that contains monetary values *Hash - sums nonfinancial numeric fields *Record count - # of records |
| Processing Controls | Data Matching, File Labels, Batch total recalculation, Cross-footing and zero-balance tests, Write protection, Concurrent update |
| Form design (input controls) | *All forms should be sequentially numbered to verify missing docs *Use of turnaround docs to eliminate input errors |
| Batch Processing Data Entry Controls (additional) | Sequence check, Error log, Batch totals |
| Online Data Entry Controls | Auto entry, Prompting, Pre-formatting, Closed-loop verification, Transaction logs, Error messages |
| Output Controls | User review of output, Clean desk policy |
| Preventive Maintenance (Availability) | Clean disk drives, Proper storage of hardware and software |
| Redundant Components (Availability) | *Provides fault tolerance, which enables the system to continue functioning despite failure of a component. EX Dual processors, RAIDs - redundant array of inexpensive disks |
| Input Controls | Form design, cancellation and storage of docs, authorization and segregation of duties, visual scanning, data entry |
| Output Controls | Reviews and reconciliation, Encryption and access controls, message acknowledgement techniques |
| Parity Checking (Output > Data Transmission Control) | A control that counts the number of odd or even bits in order to verify that all data were transmitted correctly |
| Checksum (Output > Data Transmission Control) | Sending device calculates a hash of the file |
| Business Continuity Plan | A plan that describes how to resume business ops after a major calamity. Minimize disruption and downtime. Establish alternative means of processing information. |
| Incremental Daily backup | Copying only the data items that have changed since the last partial backup; Faster to perform than differential |
| Differential backup | Copies all changes made since the last full backup; Restoration is simpler under this method. |
| Archive | A file used to store info fo long periods of time |
| Change Control | A plan to ensure that modifications to an IS do not reduce its security |
| Cold Site | A DRP plan that contracts the use of an alternate site that is prewired for Internet but has not computing or network equipment. |
| Zero-balance test | A processing control that involves use of an account that should not have a balance after processing |
| Disaster Recovery Plan | Outlines the procedures to restore an org's IT function in the event of a disaster; Periodic testing and revision are the most important components |
| Hot Site | Facility used that is prewired for internet, telephone, and contains all necessary equipment |