CHAPTER 10 AIS Questions and Answers right

CHAPTER 10 AIS Questions and Answers right Processing Integrity Principle that states that a reliable system is one that produces information that is accurate, complete, timely, and valid. What three areas must be controlled in order to obtain processing integrity? Input, Processing, and Output What are different types of input controls? Forms design, cancellation and storage of source documents, data entry controls Turnaround Document (forms design) A record of company data sent to an external party and then returned by the external party to the system as input. Field Check Determines whether the characters in a field are of the proper type (All numbers in a numeric only field Ex. no letters in zip code) Sign Check Determines whether the data in a field have the appropriate sign. (Should not be negative) Limit Check Test a numerical value against a fixed value. (Reg hours 40) Range Check Whether a number falls between lower and upper limits Size Check Will the input data fit into the assigned field? Ex. Make sure 8-digit employee number is no more than 8 numbers Completeness Check Determines whether all required data items have been entered. - ex. sales transaction records should not be accepted for processing unless they include the customer's shipping and billing address Validity Check Compares the ID code or account number in transaction data with similar data in the master file to verify that the account exists - ex. if product number 65432 is entered on a sales order, the computer must verify that there is indeed a product 65432 in the inventory database Reasonableness Test Determines the correctness of the logical relationships between two data items - ex - overtime hours should be zero for someone who has not worked the maximum number of regular hours in a pay period. Check Digit Verification Recalculating a check digit to verify that an error has not been made. This calculation can be made only on a data item that has a check digit - if an error is made in entering any of the ten digits the calculation made on the first nine digits will not match the tenth. Sequence Check Tests whether a batch of input data is in the proper numerical or alphabetical sequence Financial Total Sums a field that contains monetary values Hash Total Sums a nonfinancial numeric field Record Count counts the number of records in a batch Prompting The system requests each input data item and waits for an acceptable response - ie - prompting is an online completeness check Closed-loop verification Checks the accuracy of the input data by using it to retrieve and display other related information - ex. if a clerk enters an account number, the system could retrieve and display the account name so that the user could verify that the correct account number had been entered. Data Matching (Processing Controls) Two or more items of data that are matched before an action can take place. Header Record A file label located at the beginning of each file and contains the file name, expiration date, and other identification data Trailer Record A file label located at the end of the file and contains the batch totals calculated during the input Cross-Footing Grand totals computed by summing columns or rows and making sure they match - Zero-balance Tests Checking the credits and debits to make sure that a balance is set to 0 in a clearing account Concurrent Update Controls Prevent double-entry errors by locking out one user until the system has finished processing the transaction entered by the other Parity Bit (Output control) An extra digit added to the beginning of every character that can be used to check transmission accuracy Fault Tolerance (under Availability principle) The ability of a system to continue functioning in the event that a particular component fails Redundant Arrays of Independent Drives RAID. Data is written to multiple disk drive simultaneously. - instead of just one disk drive - thus if one disk drive fails, the data can be readily accessed from another UPS Uninterruptible Power Supply. Provides protection in the event of a prolonged power outage Backup An exact copy of the most current version of a database Recovery Point Objective RPO. The maximum amount of data that the organization is willing to potentially lose Recovery Time Objective RTO. The length of time that the organization is willing to attempt to function without its information system Real-Time Mirroring Involves maintaining two copies of the database at two separate data centers at all times and updating both copies in real-time as each transaction occurs Incremental Backup Copying only the data items that have changed since the last partial backup. (One day at a time). Quicker to backup, but longer to restore Differential Backup Copying all changes made since the last full backup. (Monday = backup + Mon, Tuesday = Backup + Mon + Tues). Simpler restoration Archive Copy of a database, master file, or software that is retained indefinitely. DRP Disaster Recovery Plan. An outline of the procedures to restore an organization's IT function in the event that its data center is destroyed by an act of terrorism or natural event.