Data and Instruction Input

INPUT CONTROLS: DATA AND INSTRUCTION INPUT

INPUT CONTROLS: DATA AND INSTRUCTION INPUTGROUP 2MEMBERS:MAXWELL BINDI R104585CONIAS GDANIEL K

INTRODUCTION:

Components in the input subsystem are responsible for bringing information into a system. This information takes two forms: first, it may be raw data to be processed; second, it may be instructions to direct the system to execute particular processes, update or interrogate particular data, or prepare particular types of output. This presentation examines controls over the capture, preparation, and entry of data and instructions into a system. DATA CAPTURE METHODS:

Historically, document based data capture has been used most frequently since the technology needed to support direct entry and hybrid methods has been costly. The costs are decreasing quickly, however, and direct entry and hybrid methods are now widely used.Document-Based Data Capture:

When document based data capture methods are used, some type of data preparation activity also is undertaken; scanning, keyboarding operation. Advantage of document based data capture is that they are easy and flexible. Documents can be readily distributed close to the points of data capture. Expensive data capture and input devices are not needed at each location where data capture occurs. However, they often require substantial amounts of human intervention.Direct Entry Data Capture:

Involves immediate recording of an event as it occurs using an input device. The risks of clerical or operator errors decrease. Immediate validation of data can be undertaken to provide operators with feedback on data capture errors. If many data capture points are required it may be difficult to provide direct entry facilities at each location.Hybrid Data Capture

uses a combination of document-based and direct entry techniques. The Hardware and Software needed to support hybrid data capture methods are still costly, however, although costs are decreasing rapidly.DATA PREPARATION METHODS.Data preparation comprise one or more of the following tasks: Converting data to machine readable form converting data from one machine readable form to another preparing batches and control totals Scanning for authenticity, accuracy, completeness, and uniqueness Verifying data converted to machine-readable form: costly and so it should be used for critical fields where errors are difficult to detect with an input validation program.DIRECT ENTRY DEVICESThey are several direct entry devices, such as voice recognition units, process control devices, light pens, joysticks, mouse. For now we look at some of the widely used.

Point-of-Sale Terminals:

Optical scanning of a pre-marked code, for e.g , the universal product code, enables faster throughput of items. Increased accuracy in pricing items Reduced price marking upon receipt of an item and upon change of the item's price. Customer satisfaction; a more detailed customer receipt is printed Improved control over tender since the terminal controls the cash drawer. Better inventory control and shelf allocation through more timely information on item sales.Automatic Teller Machines

They are designed to be physically secure they have the same anti-theft features as a safe. Camera surveillance must be undertaken, and heat, motion, and sound detectors might be installed. ATMs usually provide some type of facility for entering a cryptographic key. If device control software is not secure, fraudulent modifications can be carried out so an ATM dispenses all cash when the software recognizes a particular card.INPUT DEVICES

Input devices are used to read the data into the application. Since most input devices function reliably, however, the auditors primary concern is that a regular maintenance schedule for these devices be maintained. Nonetheless, the auditors should understand what type of errors will be prevented, detected, and corrected by the controls in the input devices.Card ReadersCard reader malfunctions occur for three reasons: cards are defective in some way. (b) Mechanical components have failed so that cards do not move across the read stations in the correct positions or during the correct timing intervals (c) electronic components have failed so that photoelectric cells or brushes in the read station fail to sense the card correctly.

To detect card reader malfunctions, four types of controls are used: Dual read: the card is read twice by two different read stations or the same read station and the results of each are compared Hole Count: the card is read twice and a count of the holes in each column and row made during each read is compared. Echo Check: The central processor sends a message to the card reader to activate the read function and the card reader returns a message to the central processor to indicate it has been activated Character Check: the card reader checks that the combination of holes read represents a valid character.SOURCE DOCUMENT DESIGN

The auditor must understand the fundamentals of good source document design. As a basic data input control, a well designed source document achieves several purposes: increases the speed and accuracy with which data can be recorded. Controls the workflow facilitates preparation of the data in machine readable form For pattern recognition devices, increases the speed and accuracy with which data can be read. Facilitates subsequent reference checkingThree decisions can be made after source document analysis:1. Choice of Medium Choices of length and width, grade and weight need to be made Choices of wrong length and width, or grade and weight can cause a variety of problems

2. Choice of Makeup

They are four types of makeup; padding, multipart set, continuous form, snap-apart sets Choice of wrong makeup results in input errors occurring through documents tearing, and data being too lightly written to be read.3.Choice of Layout and Stylesome general design guidelines are:1) Preprint wherever possible: preprint the responses and have users tick the correct response.2) Provide titles, headings, notes, and instructions3) Use techniques for emphasis and to highlight differences4) Arrange fields for ease of use5) Where possible,provide multiple choice answers to questions to avoid omissions6) Use boxes to identify field size errors7) Combine instructions with questions8) Space items appropriatel on forms:9) Design for ease of keying10) Prenumber source documents11) Conform to organization's standardsDATA CODE CONTROLS

Data codes have two purposes that is they uniquely identify an entity or identify an entity as a member of a group or a set and codes are often more efficient than textual or narrative description, since they require a smaller number of characters to carry a given amount of information.Design Requirements:A well designed coding system achieves Flexibility; easy addition of new items or categories Meaningfulness; where possible, a code should indicate the values of the attributes of the entity Compactness; Maximum information conveyed with a minimum number of characters Convenience; A code should be easy to assign, encode, decode and key. Evolvability; where possible, a code can be adapted to changing user requirements.Data Coding Errors Addition Truncation Transcription Transposition Double TranspositionTypes of Codes:

1. Serial Codes Serial coding systems assign consecutive numbers or alphabetic to an entity irrespective of the attributes of the entity. Advantage of a serial code are the ease with which a new item can be added and conciseness. Deleted items must have their codes reassigned to new items.2. Block Sequence Codes Block sequence codes assign blocks of numbers to particular categories of an entity. Block sequence code have the advantage of giving some mnemonic value to the code. They are problems in choosing the size of the block needed(and the remedy if overflow occurs) and ensuring blocks are not too wasted large so wasted characters occur and the code is no longer concise.3. Hierarchical Codes They require the selection of the set of attributes of the entity to be coded and their ordering in terms of importance. The value of the code for the entity is a combination of the values of the codes for each attribute of the entity they are more meaningful to their users. They carry more information about the entity to which they are assigned sometimes they present problems when changes occur.4. Association Codes

the attributes of the entity to be coded are selected and unique codes assigned each attribute value. The code for the entity is simply a linear combination of the different codes assigned the attributes of the entity They carry substantial information about the entity they represent. They are not concise. An example is SHM32DRCOTCHECK DIGITSIn some cases errors made in transcribing or keying data can have serious consequences. One control used to guard against these types of errors is a check digit.Calculating Check Digits A check digit is a redundant digit added to a data code that enables the accuracy of other characters in the code to be checked If the code contains alphabetic, a check digit can still be calculated. Each alphabetic must be assigned a number according to some rule.When to use Check Digits Use of check digits should be limited to critical fields Where possible, the computer should assign new codes with their check digits Checking of check digits should take place only by machine to save storage space the check digit can be dropped once it has been read into the machine and recalculated upon outputINSTRUCTION INPUT

- Ensuring the quality of instruction input to a computer system is a more difficult objective to achieve than to ensure the quality of data input. - Users often attempt to communicate complex actions that they want the system to undertake. - On the other hand the input subsystem needs to provide considerable flexibility so users can accomplish their processing objectives. On the other hand, it needs to exercise careful control over the actions they undertake. The languages used to communicate instructions to the system tend to trade off flexibility with control.Question-Answer Dialogs

Used primarily to obtain data input. Also can be used to obtain instruction input in conjunction with the data input. In those cases where the required answers are not obvious, a help facility can be used to assist inexperienced users. Effectiveness and efficiency issues are of primary concern For experienced users, the alternating sequence of question and answer may be slow and frustrating. Experienced users may be allowed to stack answers or change to another language mode.AUDIT TRAIL CONTROLSWith the data input and instruction input functions, the audit trail in the input subsystem maintains the chronology of events from the time data and instructions are captured until they are entered into the system.

Accounting Audit Trail A source document should show who prepared the document, who authorized the document, when it was prepared, what account or record to be updated, and the batch number of the physical batch in which the document is to be included. With direct entry data capture, the input program must attach certain audit trail data to the input record e.g the identity of the terminal operator, the identity of the terminal, the time and date of input, and a unique reference number for the transaction that will be carried through the system. In the case of instruction input, the input subsystem must retain a record on magnetic media containing such data items as the originator of the insructions, the type of instruction and its arguments, the results produced, and the time and date of entry of the instruction. Sometimes a hardcopy of the instruction is available.Operations Audit TrailSome of the types of operations audit trail data that might be collected are. Time to key in a source document at a terminal number of read errors made by an OCR device number of keying errors identified during verification frequency with which an instruction in a command language is used. Time taken to execute the same instruction using a light pen vs a mouseBy analyzing this data, error-prone input activities can be identified and remedial action taken the time taken to enter data on a screen may indicate that more user training is needed or a screen redesign is necessary.END OF PRESENTATION