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540f07cost12oct41 Reviews Postmortem u Surprises? u Use white background on slides u Do not zip files on CD u Team leader should introduce team members.

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Presentation on theme: "540f07cost12oct41 Reviews Postmortem u Surprises? u Use white background on slides u Do not zip files on CD u Team leader should introduce team members."— Presentation transcript:

1 540f07cost12oct41 Reviews Postmortem u Surprises? u Use white background on slides u Do not zip files on CD u Team leader should introduce team members u Submit revised plans/schedules by Wed u Other issues u How to help remember comments –Suggestions

2 540f07cost12oct42 Putnam's Cost Estimation Model u macro-estimation model that uses LOC u relationship between cost and the amount of time available for the development effort. u The model supports the 'mythical man- month' idea

3 540f07cost12oct43 Rayleigh Curve u y : instantaneous programmer-power u K : total lifecycle cost ( in programmer-years) u t : time from beginning of project u td: delivery time u e= 2.71828...

4 540f07cost12oct44 Software Equation u There must be a relationship between the lifecycle development effort, the development time and the size of the project. u This relationship is given in the Software Equation

5 540f07cost12oct45 Software Equation u S s = C*K 1/3 t d 4/3 – where: – S s is the estimated size of the software system – K is the total lifecycle effort in programmer-years – C is the technology constant – t d is the development time (in years) B is “special skills factor”; P is “productivity parameter”

6 540f07cost12oct46 Putnam by spread-sheet

7 540f07cost12oct47 Question of the Day u Which of the following things measure the “size” of the project in terms of the functionality that has to be provided in the project? u inputs, outputs, classes/objects, methods, files, reports, commands, records u What other things might be counted?

8 540f07cost12oct48 Cost Estimation Using Function Points

9 540f07cost12oct49 Function Points u Attempting to measure “functionality” u widely used in business applications u IFPUG

10 540f07cost12oct410 Program Features u outputs u inquiries u inputs u files u interfaces

11 540f07cost12oct411 Pressman, Soft Eng, 5th Ed u Outputs – “Each user output that provides application- oriented information to the user is counted. In this context output refers to reports, screens, error messages, and so on. Individual data items within a report are not counted separately”

12 540f07cost12oct412 Pressman, Soft Eng, 5th Ed u Inputs – “Each user input that provides distinct application-oriented data to the software is counted. Inputs should be distinguished from inquiries, which are counted separately” u Inquiries – “An inquiry is defined as an on-line input that results in the generation of some immediate software response in the form of an on-line output. Each distinct inquiry is counted.”

13 540f07cost12oct413 Pressman, Soft Eng, 5th Ed u Files – “Each logical master file (I.e. a logical grouping of data that may be one part of a large database or a separate file), is counted” u External interfaces – “All machine readable interfaces (e.g. data files on tape or disk) that are used to transmit information to another system are counted.”

14 540f07cost12oct414 Dreger, FPA, 1989 u “A function point is defined as one end-user business function” u “business functions made available to the user are identified” u “outputs are items of business information processed by the computer for the end user”

15 540f07cost12oct415 Dreger, FPA, 1989 u Inquiries “are direct inquiries into a data base or master file that look for specific data, use simple keys, require immediate response and perform no update functions” u “Inputs are items of business data sent by the user to the computer for processing and to add, change, or delete something.” u “Files are data stored for an application, as logically viewed by the user”

16 540f07cost12oct416 Dreger, FPA, 1989 u Outputs – “count each of the outputs leaving the context diagram ‘area under study’ at the lowest (greatest detail) level of the logical … data flow diagram system” – count separately if different format or different processing u Dreger says detail lines and total lines are different, ifpug says no

17 540f07cost12oct417 Dreger, FPA, 1989 u Inputs – “count each unique user data or control input that enters the application boundary and also updates (adds to, changes, or deletes from) a logical internal file, data set, table or independent data item.” – “count as one input each uniquely formatted or processed portion...”

18 540f07cost12oct418 Dreger, FPA, 1989 u Files –“count each major logical group of user data or control information” u Interfaces –“count as one interface each major logical.. file or other logical group of user-approved data or control information within the application boundary that is set to, shared with, or received from another application.”

19 540f07cost12oct419 Weights for features u simple average complex u outputs 4 5 7 u inquiries 3 4 6 u inputs 3 4 6 u files 7 10 15 u interfaces 5 7 10

20 540f07cost12oct420 TTYP1 u Identify the inputs, outputs, enquiries, files and interactions for the following task. u A doctor’s appt_system makes appointments for patients. Patients select type of visit and asks for specific time or next available or times on a specific date. System offers choices and allows patient to select and/or confirm appointment.

21 540f07cost12oct421 Questions u Does the system require reliable backup and recovery? u Are data communications required? u Are there distributed processing functions? u Is performance critical? u Will the system run in an existing, heavily utilized operational environment?

22 540f07cost12oct422 Questions u Does the system require on-line data entry? u Does the on-line data entry require the input transaction to be built over multiple screens or operations? u Are the master files updated on-line? u Are the inputs, outputs, files, or inquiries complex? u Is the internal processing complex?

23 540f07cost12oct423 Questions u Is the code designed to be reusable? u Are conversion and installation included in the design? u Is the system designed for multiple installations in different organizations? u Is the application designed to facilitate change and ease of use by the user?

24 540f07cost12oct424 Adjusted Function Points u FP = FP unadjusted * (.65 + 0.01 * (sum of ratings ) )

25 540f07cost12oct425 TTYP2 u What if function points are not equal in effort? u How could you adjust your counting?

26 540f07cost12oct426 For Tuesday u Review for exam –Review types of questions from Tues, Sep 25 –Review cost estimation


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