Chapter 10 Flashcards
Turnaround document
a record of company data sent to an external party and then returned by the eternal party to the system as input.
Field check
determines whether the characteristics in a field are of the proper type. (no letters in a zip code entry)
Sign Check
determines whether the data in a field have been appropriate arithmetic sign (no negatives)
Limit Check
tests a numerical amount against a fixed value. (work hours are less or equal to 40 hours a week)
Range check
tests whether a numerical amount falls between predetermined lower and upper limits.
size check
ensures that the input data will fit into the assigned field. (SS number is always 8)
Completeness check
on each input record determines whether all required data items have been entered.
Validity Check
compares the ID code or account number in transactions data with similar data in the master file to verify that the account exists (school id number)
Reasonableness test
determines the correctness of the logical relationship between two data items.
Check Digit Verification
data entry devices perform by using the first 9 digits to calculate the 10th digit each time an ID number is entered.
Sequence Check
tests whether a batch of input data is int he proper numerical or alphabetical sequence.
Batch totals
summarize important values for a batch of input records.
Financial Total
sums a field that contains monetary values, such as dollar amount of all sales for a batch of sales transactions
Hash totals
sums a non-financial numeric field, such as the total of the quantity ordered field in a batch of sales transactions
record count
the number of records in a batch.
Prompting
the system requests each input data item and waits for an acceptable response, ensures that all necessary data are entered.
Closed-Loop Verification
checks the accuracy of input data by using it to retrieve and display other related information.
Data Matching
two or more items of data must be matched before an action can take place
File Labels
neet to be checked to ensure that the correct and most current files are being updated.
header record
located at the beginning of each file and contains the file name, expiration date, and other identification data
trailer record
located at the end of the file and contains the batch totals calculated during input.
Cross-footing balance test
compares the results produced by each method to verify accuracy
Zero-balance test
compares the results produced by each methods to verify accuracy = 0
Write-protection mechanisms
protect against overwriting or erasing of data files stored on magnetic media
Concurrent Update Controls
prevent such errors by locking out one user until the system has finished processing the transaction entered by the other.
Fault tolerance
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 drives simultaneously. If one disk drive fails, the data can be readily accessed from another
Uninterruptible power supply (UPS)
system provides protection in the event of a prolonged power outage, use battery power to enable the system to operate long enough to back up critical data and safely shut down.,
Key controls for system downtime
- preventive maintenance
- fault tolerance
- data center location and design
- training
- patch management and antivirus software.
Key controls to quick and complete recovery and resumption of normal operations
- backup procedures
- disaster recovery plan (DRP)
- Business Continuity Plan (BCP)
Recovery Point Objective (RPO)
represents the max amount of data that the organization is willing to potentially lose
Recover Time Objective (RTO)
represents the length of time that the organization is willing to attempt to function without its information system
Rel-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
involves copying only the data items that have changed since the last PARTIAL back up.
Differential Backup
copies all changes made since the last FULL back up. each new file contains the cumulative effects of all activity since the last full back up.
Disaster Recovery Plan (DRP)
outlines the procedures to restore an organizations IT function int he vent that its data center is destoyed by a natural disaster or act of terrorism.
Cold Site
an empty building that is prewired for necessary telephone and internet access, plus a contract with oen or more vendors to provide all necessary equipment within a specified period fo time.
Hot site
A facility that is not only prewired for telephone and internet access but also contains all the computing and office equipment the organization needs to perform its essential business activities.
Business Continuity Plan (BCP)
specifies how to resume not only IT operations, but all business processes, including relocating to anew office and hiring temporary replacements, in the event that a major calamity destroys not only an organization’s data center but also its main headquarters.
Key components of effective disaster recover and business continuity plans:
- Data backup procedures
- Procedures for access to replacement infrastructure
- through documentation
- periodic testing and training
- adequate insurance.
Backup
an exact copy of the most current version of a database. Intended for use in the event of a hardware or software failure.
Restoration
the process of installing the backup copy for use
Archive
a 100% copy of a database, master file, or software. Retained indefinitely. Often matches reporting period/ fiscal year.
