BTC1110 Lecture Notes - Lecture 17: Write Protection, Check Digit
6 Jun 2018
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Professor
Question 4 –Week8
Control Matrix- Internal Control
Input Controls
(1) Form Design:
All forms should be sequentially pre-numbered (to verify completeness –No missing documents and
reconcile processing)
Use of turnaround documents (→reduce errors)
(2) Cancellation and Storage of source for errors & emissions
(3) Data entry controls: (Accurate)
Field type check (proper
character)
Sign check (+/-)
Limit check (against fixed value:
E.g. hr. worked)
Range check (within the range)
Field size check (#. Of characters)
Completeness check
(mandatory field check to ensure
all required dada has been entered)
Validity check: input compared
with master data →Confirm
existence
Reasonableness check (logical
comparison)
Check digit verification
Prompting (input requested by
system)
Closed-loop verification
(Comparison)
Transaction logs
(4) Batch input controls:
Group a batch of transactions and manually calculate the totals and compare to the computer-input batches totals
Processing Controls
Data matching
File labels: Ensure correct and
most current file is being
updated
Batch total calculation
Cross footing and 0 balance tests:
Compare totals using multiple
methods
Write protection: Eliminating
possibility of overwriting/ erasing
existing data
Concurrent update controls:
Locking records when they are
updated →Multiple users are not
updating at the same time (lost
update)
Input Controls
(1) User review of output
(2) Reconciliation procedures
(3) Data Transmission Controls:
TCP assigns sequence numbers to data “packets”
Check sums (hash of file transmitted, comparison made of hash before and after transmission)
Parity checking (bit added to each char. Transmitted the characters →verified)
Document Summary
E. g. hr. worked) (cid:120) range check (within the range) (4) batch input controls: (cid:120) field size check (#. Group a batch of transactions and manually calculate the totals and compare to the computer-input batches totals. Processing controls (cid:120) data matching (cid:120) file labels: ensure correct and most current file is being updated (cid:120) batch total calculation (cid:120) cross footing and 0 balance tests: Compare totals using multiple methods (cid:120) write protection: eliminating possibility of overwriting/ erasing existing data (cid:120) concurrent update controls: Locking records when they are updated multiple users are not updating at the same time (lost update)
