Ch04 6w4f2m

Chapter 4—Documenting Information Systems TRUE/FALSE 1. In a DFD, a bubble symbol shown below depicts a function or a process within which

incoming data flows are transformed into outgoing data flows.

ANS: T 2. In a DFD, a square represents an internal entity

ANS: F 3. In a DFD, two parallel lines represent the data store symbol

ANS: T 4. The following symbol represents general purpose input-output

ANS: F 5. The following symbol represents a manual process

ANS: T

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6. The following symbol represents a disk

ANS: F 7. The following symbol represents paper filing.

ANS: T 8. The following symbol represents a computer process

ANS: T 9. In a DFD, an external entity symbol portrays a source or a destination (sink) outside the

system. ANS: T 10. A context diagram is the top-level diagram in a series of data flow diagrams representing an

information system and it shows the flows into and out of the system of interest and into and out of external entities. ANS: T 11. Internal entities are those persons, places, or things outside our system that send data to, or

receive data from, our system. ANS: F 12. An external entity is a person, place, or thing within the system that transforms data. ANS: F

Documenting Information Systems 53 13. A physical data flow diagram uses bubbles to specify where, how, and by whom a system's

processes are accomplished. ANS: T 14. When the context diagram and the level 0 diagram reflect the equivalent external data flows,

the two diagrams are said to be balanced. ANS: T 15. The successive subdivision, or "exploding," of logical DFDs is called bottom up partitioning. ANS: F 16. A systems flowchart is a graphical representation of both the physical and logical features of

an information system. ANS: T 17. Processes that handle other-than-normal situations are called exception routines. ANS: T 18. Information processing activities including retrieving data from a file, transforming data, or

filing data. ANS: T 19. An acceptance stub is a data flow that leaves a bubble but does not go to any other bubble or

file and indicates processing that is performed in other than normal situations. ANS: F 20. In an enterprise system, we would have one data store/disk symbol that would be labeled

“enterprise database” instead of two or more data store symbols. ANS: T 21. When we convert to an enterprise system, reengineered processes often result from the

installation and can cause changes throughout the systems flowcharts. ANS: T

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MULTIPLE CHOICE 1. A symbol used in data flow diagrams to depict an entity or process within which incoming data flows are transformed into outgoing data flows is a(n): a. data flow symbol b. external entity symbol c. bubble symbol d. file symbol ANS: C 2. A data flow diagram could contain each of the following symbols except: a. a bubble or circle b. a non-square rectangle c. a square d. a curved line with arrow head ANS: B 3. Which of the following symbols is represented by two parallel lines? a. data flow symbol b. external entity symbol c. sink symbol d. file symbol ANS: D 4. Which symbol portrays a source or destination of data outside the system? a. data flow symbol b. external entity symbol c. bubble symbol d. file symbol ANS: B 5. Those entities which perform no information processing activities for the system are called: a. external entities b. internal entities c. boundary entities d. environmental entities ANS: A 6. Which symbol can be either an entity or a process depending on the type of DFD? a. bubble symbol b. external entity symbol c. data flow symbol d. file symbol ANS: A

Documenting Information Systems 55 7. Which of the following is the least detailed of the data flow diagrams? a. logical data flow diagram b. systems flowchart c. context diagram d. physical data flow diagram ANS: C 8. In a physical data flow diagram, a bubble or circle could be used to specify each of the following except: a. where a process is performed b. how a process is performed c. by whom a process is performed d. what process is performed ANS: D 9. Which type of data flow diagram specifies where, how, and by whom a system's processes are performed? a. context diagram b. physical data flow diagram c. logical data flow diagram d. systems flowchart ANS: B 10. A person, place, or thing within a system that transforms data is called: a. external entity b. relevant environment c. internal entity d. boundary ANS: C 11. Which data flow diagram shows a system's processes and the flow of data into and out of the processes? a. context diagram b. physical data flow diagram c. systems flowchart d. logical data flow diagram ANS: D 12. Data flow labels in context diagrams usually describe: a. what the data are (physical labels) b. the nature of the data (logical labels) c. to whom the data are being transmitted (identity labels) d. where the data are being sent (directional labels) ANS: B

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13. In which of the following DFDs does the bubble symbol represent a process and not the entire system? a. context diagram b. physical data flow diagram c. logical data flow diagram d. systems flowchart ANS: C 14. In a logical DFD for a cash receipts system, each of the following labels might appear in a bubble except: a. cashier b. capture cash receipts c. endorse checks d. update master files ANS: A 15. The data flows in a logical flow diagram show: a. how the data are transmitted b. where the data are transmitted c. the nature of the data being transmitted d. who receives the transmitted data ANS: C 16. When two data flow diagrams have equivalent external data flows, we say that the two data flow diagrams are: a. congruent b. similar c. balanced d. equal ANS: C 17. A process in which successive layers of data flow diagrams are constructed by "exploding" the bubbles on a less detailed DFD to show more detailed data flows is called: a. top-down partitioning b. serial expansion c. balanced construction d. expanded data flows ANS: A 18. Which of the following is statements related to the construction of data flow diagrams is false? a. The level 0 diagram is the next level down from the context diagram. b. If the level 0 diagram has one arrow going into bubble number 1.0 and two arrows leaving bubble number 1.0, then diagram 1.0 will show one arrow entering and two arrows leaving. c. Sources and destinations are depicted by parallel horizontal lines, between which the name of the entity is shown. d. Arrows represent a pathway for data. ANS: C

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19. When constructing data flow diagrams: a. as a bubble expands from level 0 to level 1 and then to level 2, the numbering of the bubbles goes from 0.1 to 1.1 to 2.1, respectively b. external entities do not appear below the level 0 diagrams c. exceptions are always presented d. data flow symbols only appear in context diagrams or level 0 DFDs ANS: B 20. A systems flowchart varies from a data flow diagram because it: a. only represents the information system b. only represents the operations system c. represents both the information system and the operations system d. represents the information system, the operations system, and the management system ANS: D 21. Information processing activities include: a. only automated activities b. activities that retrieve, transform, and file data c. the sending of data between entities d. operational activities ANS: B 22. Why do auditors and systems analysts use systems documentation? a. to understand, explain, and improve complex systems b. to only provide justification to management for systems investments c. to reduce the number and amount of external entities d. to eliminate evidence to be collected ANS: A 23. On a systems flowchart, computer processing is represented by a: a. square b. trapezoid c. rectangle d. parallelogram ANS: C 24. On a systems flowchart, a paper file is represented by a: a. triangle b. cylinder c. rectangle d. pentagon ANS: A

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25. On a systems flowchart, a dashed line with an arrow going from one symbol such as that for a magnetic tape to a second copy of that same symbol indicates: a. only some data are ed between the two devices b. the two devices operate simultaneously in parallel c. documents but not electronic data flow between the two devices d. one copy is the original which is to be replaced after updating by the other copy ANS: D 26. Which of the following systems flowcharting symbol descriptions is incorrect?

a. b. c. d.

disk computer process manual process CRT display

ANS: C 27. Which of the following systems flowcharting symbols descriptions is incorrect?

a. b. c. d.

tape on-page connector start/stop paper file

ANS: D

Documenting Information Systems 59 28. Which of the following systems flowcharting symbols descriptions is incorrect?

a. b. c. d.

general purpose input-output manual operation multiple-page document punched card

ANS: D 29. How many bubbles are included in a correctly drawn context diagram? a. zero b. one c. three d. more than one but no more than are necessary to model the system ANS: B 30. An information processing activity could be any of the following except: a. sending or receiving data b. preparing documents c. data entry d. ing data ANS: A 31. In drawing a context diagram, we should include: a. only that portion of a narrative description which relates to data transformation b. only that portion of a narrative description which describes external entities c. all activity described in a system narrative d. only that portion of a narrative description which describes data flows ANS: C 32. How many bubbles should be used in a logical data flow diagram? a. one b. three to five c. five to seven d. as many as needed but no more than five ANS: C

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33. On a logical data flow diagram, data flows: a. always go from a higher-numbered to a lower-numbered bubble b. never go from a higher-numbered to a lower-numbered bubble c. can go in either direction as needed d. must go from a bubble to a box ANS: B 34. In general, a process bubble appearing in a level 0 data flow diagram reflects: a. the sending of a document from one department to another b. the filing of a document c. the updating of a file d. the transformation of data ANS: D 35. All of the following are "guidelines" for grouping activities in a level 0 DFD except: a. group activities if they occur in the same place and at the same time b. group activities if they are performed by the same entity but at different times c. group activities if they occur at the same time but in different places d. group activities in order to eliminate single-activity bubbles wherever possible ANS: B 36. When a transaction cannot be processed in a routine fashion because of an error or other processing problems, the transaction must be handled by a(n): a. rejection routine b. change report c. exception and summary report d. exception routine ANS: D 37. The following is a jumbled list of the activities suggested in this text for drafting data flow diagrams for an existing system: I. II. III. IV. V.

Prepare a table of entities and activities. Prepare a chronologically sorted table of entities and activities. Draw a physical data flow diagram. Draw a logical data flow diagram. Draw a context diagram.

The best sequence for undertaking these activities is: a. I, II, V, III, IV b. I, V, III, II, IV c. II, I, III, V, IV d. II, IV, III, I, V ANS: B

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38. Examine the following context diagram and the related level 0 logical data flow diagram. Which of the following statements is true? 39.

a. b. c. d.

The data flow diagrams are prepared correctly. A context diagram must have a least two external entities. The logical data flow diagram is not balanced. The logical data flow diagram must have 5 to 7 processes.

ANS: C

39. Which statement concerning the following 1.0 data flow diagram is true?

a. b. c. d.

The data flow diagram follows DFD guidelines. An arrow should never leave a bubble with no destination. Data should only flow from a data store. Level 1.0 diagrams should show the external entities.

ANS: A

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40. Which of the following segments violates guidelines for creating systems flowcharts?

a. b. c. d.

Segment a. Segment b. Segment c. Segment d.

ANS: A 41. The following systems flowchart describes how a data entry clerk key enters data on a source document into business event data. Which statement describes whether the systems flowchart was created properly?

a. b. c. d.

The systems flowchart was created properly. The arrow between the computer process and the data store should be bi-directional. The computer process should be shown in the computer column. The second symbol in the data entry clerk column should be a square.

ANS: C

Documenting Information Systems 63 42. The following systems flowchart describes how a manager queries a data store to view information on a computer screen. Which statement describes whether the systems flowchart was created properly?

a. The systems flowchart was created properly. b. Only a single direction arrow should flow from the data store symbol to the process query symbol. c. The input query symbol should be a square. d. The input query symbol should be in the computer column. ANS: B 43. The following systems flowchart describes how a enters business event data from a source document to update master file data. Which statement describes whether the systems flowchart was created properly?

a. b. c. d.

The systems flowchart was created properly. Only a single disk must be used to represent the master data. The every day symbol should be connected with a solid line. The data flows should move from the upper-left to lower-right corners of the systems flowchart.

ANS: D 44. The flow of processes on a system flowchart is from: a. upper left to lower right b. upper right to lower left c. right to left either upper or lower corners d. left to right either upper or lower corners ANS: A

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COMPLETION 1. In a DFD, a(n) ____________________ depicts a function or a process within which incoming data flows are transformed into outgoing data flows. ANS: bubble symbol 2. In a DFD, a(n) ____________________ represents a pathway for data. ANS: data flow symbol 3. A(n) ____________________ is an external entity on a DFD that receives data from the system. ANS: destination (sink) 4. A(n) ____________________ is an external entity on a DFD that sends data from outside the system. ANS: source 5. In a DFD, a(n) ____________________ portrays a source or a destination (sink) outside the system. ANS: external entity symbol 6. A(n) ____________________ is the top-level diagram in a series of ____________________ diagrams representing an information system, and it shows the flows into and out of the system of interest and into and out of external entities. ANS: context diagram data flow 7. ____________________ are those persons, places, or things outside our system that send data to, or receive data from, our system. ANS: External entities 8. A(n) ____________________ is a person, place, or thing within the system that transforms data. ANS: internal entity 9. A(n) ____________________ uses bubbles to specify where, how, and by whom a system's processes are accomplished. ANS: physical data flow diagram 10. A(n) ____________________ DFD depicts what tasks the system performs rather than how, where, or by whom they are performed. ANS: logical

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11. When the context diagram and the level 0 diagram reflect the equivalent external data flows, the two diagrams are said to be ____________________. ANS: balanced 12. The successive subdivision, or "exploding," of logical DFDs is called ____________________. ANS: top-down partitioning 13. A(n) ____________________ is a graphical representation of both the physical and logical features of an information system. ANS: systems flowchart 14. A(n) ____________________ originates, transforms, files, or receives data. ANS: activity 15. ____________________ activities include retrieving data from a file, transforming data, or filing data. ANS: Information processing 16. Processes that handle other-than-normal situations are called ____________________ or ____________________ routines. ANS: exception error 17. A(n) ____________________ is a data flow that leaves a bubble but does not go to any other bubble or file and indicates processing that is performed in other-than-normal situations. ANS: reject stub 18. In a(n) __________ system, we use a central database for the business processes. ANS: enterprise

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PROBLEM 1. Figure TB-4.1 is a "generic" level 0 data flow diagram, taken from Figure 4.5 in the text. Required: Using good DFD construction techniques, draw a diagram to explode bubble 3.0 to its next lower level. Diagram 3.0 should contain three processes, appropriately numbered, and should contain the following data flows in addition to those in the level 0 diagram (see NOTE): a. b. c.

Flow H runs from the first process to the second. Flow I runs from the first process to the third. Flows J and K run from the second process to the third.

NOTE: Assume that the flows shown in the level 0 diagram affect diagram 3.0 as follows: 1. 2. 3.

Flow D runs to the first process in diagram 3.0. Flow B runs from the third process in diagram 3.0. The data flow running from the data store runs to the second process in diagram 3.0.

Documenting Information Systems 67 ANS:

2. Figure TB-4.3 shows a context diagram a cash sales system. The diagram intentionally violates several of the guidelines and other techniques presented in the text for drawing DFDs. Required: Identify as many of the errors in DFD construction as you can. In the diagram, place consecutive numbers (each in a circle) next to the points at which the errors exist. On your solution sheet, list the numbers and write a one- to two-sentence description of each error and what the correct procedure should be. Error 1 is provided as an example of how to construct the solution. Error 1

Error Description Data flows should not connect two external entities. Depending on the extent of the system being analyzed, either the mail room or the bank entity should be eliminated [or be brought (documented) within the system].

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ANS: INSTRUCTOR NOTE: You may wish to modify the requirement in one of two ways: (1) Have the students redraw the diagrams instead of describing the errors or (2) limit the number of errors required in the solution to something less than the entire population. (Figure TB-4.4, an annotated version of Figure TB-4.3, shows the location of each error.) Error 2 3 4 5

Error Description When multiple entities operate identically, one box can represent all. Eliminate all but one customer box and label it "Cash customer." A context diagram should have only one bubble. Since the problem states that we are analyzing a cash sales system, eliminate the first bubble. In the context diagram and level 0 diagram, logical rather than physical labels should be used. Eliminate the reference to Form S92. The symbols used for the sales transaction event data file is incorrect. In a DFD, the file symbol is a pair of parallel, horizontal lines.

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3. Figure TB-4.5 shows a level 0 logical data flow diagram for a billing system. The logical data flow diagram intentionally violates several of the guidelines and other techniques presented in the text for drawing DFDs. Required: Identify as many of the errors in the logical DFD construction as you can. In the logical DFD, place consecutive numbers (each in a circle) next to the points at which the errors exist. On your solution sheet, list the numbers and write a one- to two-sentence description of each error and what the correct procedure should be. If an error occurs in more than one place, mark each occurrence of the error. Error 1 is provided as an example of how to construct the solution. Error 1

Error Description A data flow to an external entity should describe the document. After recording the sale, a total of the sales and the sales invoice (copy 3) may be sent to the s receivable department.

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ANS: INSTRUCTOR NOTE: You may wish to modify the requirement in one of two ways: (1) Have the students redraw the diagram instead of describing the errors or (2) limit the number of errors required in the solution to something less than the entire population. (Figure TB-4.6, an annotated version of the logical data flow diagram in Figure TB-4.5, shows the location of each error.)

Documenting Information Systems 71 Error 2 3 4 5 6 7 8

Error Description The bubbles in the level 0 DFD are numbered incorrectly. They should be numbered 1.0, 2.0, and 3.0. The label in the first bubble is a noun, referring to a physical entity. In a logical DFD, the process labels should contain verbs describing what is done. Change the label to say something like "Prepare sales invoice." In a logical DFD, there can be no backward flows. Either the recorded sales invoice flow should be eliminated, or it should go to a subsequent process bubble for action, or to a file of sales invoices. The symbols used for the price list, and inventory master data are incorrect. In a DFD, the file symbol is a pair of parallel, horizontal lines. Reject stubs should appear only in lower-level DFDs. Eliminate the reject stub from the level 0 diagram. The data flow should be from the 1.0 bubble to the customer Instructor Note: You could also include number 8 at three points. Remove “original”, “copy 2”, and “copy 3” from the sales invoice labels since they are physical details and do not normally belong in a logical DFD.

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4. Figure TB-4.7 shows several systems flowchart routines that intentionally violate good flowchart construction procedures. Required: Redraw each of the routines so that they conform to the guidelines and other techniques presented in the text for drawing systems flowcharts. HINT: Be alert to the description of each routine; the descriptions should govern your solution.

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ANS: INSTRUCTOR NOTE: You may wish to modify the requirement in one of two ways: (1) Have the students describe the violations instead of redrawing the flowchart segments or (2) limit the number of drawings required in the solution to only certain of the routines in Figure TB-4.7

Documenting Information Systems 75

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Documenting Information Systems 77

5. The following narrative describes Aegis Company's billing procedures: Each evening the shipping department at Aegis Company forwards, to the billing department, copy 2 of all shipping notices for goods shipped to customers that day. The next day a billing clerk starts the billing process by obtaining unit sales prices from a price list book and noting the prices on the shipping notice. He then types a three-part invoice for each shipment, mails the original (copy 1) to the customer, and files copy 2 by customer name. From invoice copy 3, the clerk prepares a batch total, staples the total to the batch of invoices, and sends the batch to the data processing department.

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In data processing, a data control clerk first enters the invoice batch total in a control log. Then a data entry clerk keys each invoice on a key-to-disk machine. The disk that is produced by the keying operation is sorted in customer number order using a computer sort utility. At 5:00 p.m. each evening, the invoice event data is run, together with the previous day's s receivable master data, to produce an updated master data. The update run also generates a daily summary report which is compared with the batch control log total. If the totals agree (see NOTE), the report is stapled to the batch of invoices, and the package is filed by date. NOTE: Exception routines are beyond the narrative's scope. Required: a. b. c.

Prepare a table of entities and activities. Prepare a context diagram. Prepare a physical data flow diagram.

ANS: INSTRUCTOR NOTE: This problem describes the same system used in Problem 4-6. This problem requires students to prepare selected components of systems documentation. In contrast, Instructors wishing to focus on the creation of data flow diagrams can provide their students with the solution to part a. a. Table of Entities and Activities Entities Shipping department

Activities 1. Forwards copy 2 of shipping notices to billing department

Billing clerk

2. Obtains unit sales prices from price list book 3. 4. 5. 6. 7. 8.

Notes sales prices on shipping notices Types a three-part invoice Mails original invoice to the customer Files copy 2 of the invoice by customer name Prepares a batch total of the invoices Staples the batch total to invoice (copy 3)

9. Sends the batch to data processing Customer Data control clerk

10. Enters batch total in control log 11. Compares daily summary report with control log total 12. Staples daily summary report to batch of invoices 13. Files the package of invoices, batch total, and summary report

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Data entry clerk (data preparation) Computer

b. See Figure TB-4.8.

c. See Figure TB-4.9.

14. Keys each invoice on a key-to-disk machine 15. Sorts the invoice business event data 16. Runs the invoice events data and previous day's s receivable master data 17. Updates the s receivable master data 18. Generates a daily summary report

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6. Each evening the shipping department at Aegis Company forwards, to the billing department, copy 2 of all shipping notices for goods shipped to customers that day. The next day a billing clerk starts the billing process by obtaining unit sales prices from a price list book and noting the prices on the shipping notice. He then types a three-part invoice for each shipment, mails the original (copy 1) to the customer, and files copy 2 by customer name. From invoice copy 3, the clerk prepares a batch total, staples the total to the batch of invoices, and sends the batch to the data processing department. In data processing, a data control clerk first enters the invoice batch total in a control log. Then a data entry clerk keys each invoice on a key-to-disk machine. The disk that is produced by the keying operation is sorted in customer number order using a computer sort utility. At 5:00 p.m. each evening, the invoice event data is run, together with the previous day's s receivable master data, to produce an updated master data. The update run also generates a daily summary report which is compared with the batch control log total. If the totals agree (see NOTE), the report is stapled to the batch of invoices, and the package is filed by date.

Documenting Information Systems 81 NOTE: Exception routines are beyond the narrative's scope. Required: a. b. c.

Prepare a chronologically sorted table of entities and activities. Indicate on this table the groupings--bubble numbers and bubble titles--to be used in preparing the level 0 logical data flow diagram. Prepare a logical data flow diagram (level 0 only). The context diagram of this billing system shows two external entities: shipping department and customers. Prepare a systems flowchart.

ANS: INSTRUCTOR NOTE: This problem describes the same system used in Problem 4-4. These problems require students to prepare selected components of systems documentation. In contrast, Problem 4-6 is a comprehensive problem that requires students to originate all systems documentation. Instructors wishing to focus on the creation of data flow diagrams and systems flowcharts can provide their students with the solution to part a. a. Chronologically Sorted Table of Entities and Activities Entities Billing clerk

1. 2. 3. 4. 5. 6.

Activities Obtains unit sales prices from price list book Notes sales prices on shipping notices Types a three-part invoice Files copy 2 of the invoice Prepares a batch total of the invoices Staples the batch total to invoice copies (copy 3)

Data control clerk

7.

Enters batch total in control log

Data entry clerk

8.

Keys each invoice on a key-to-disk machine

Computer

9. 10.

Sorts the invoice events data Runs the invoice events data and previous day's s receivable master data Updates the s receivable master data Generates a daily summary report

11. 12. Data control clerk

b. See Figure TB-4.10.

13. 14. 15.

Compares daily summary report to control log total Staples daily summary report to batch of invoices Files the package of invoices, batch total and summary report

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c. See Figure TB-4.11.

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7. Figure TB-4.16 contains 14 symbols used in constructing DFDs or system flowcharts. Each symbol has been assigned a capital letter (A through N) for identification in this problem. The following is a list of 14 DFD or flowcharting symbols: 1. 2.

File (in a DFD) Process (in a DFD)

84 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14.

Chapter 4 External entity (in a DFD) Document (or output or report) Manual keying of inputs Computer process Manual process CRT display Disk file Paper file Off-page connector Start/stop Annotation Batch total

Required: Match each symbol to its corresponding description by writing the description number below the each symbol.

ANS: 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14.

G I E N L C A B M D J H K F