CSC 205 Programming II Lecture 1 PSP

The Importance of High-Quality Work Three aspects to doing an effective software engineering job producing quality product doing the work for the expected costs completing the work on the agreed schedule Failure to fulfill these aspects will result in serious consequences business failures for s/w development organizations poor grades for students in a programming class

Software Development Activities and Artifacts Specificationsystem requirements specs (SRS) Designsystem design specs (SDS) Planningproject plan (including risk planning) Verification Codingsource code, conf files and executables Testingtest plans and reports Production Maintenancerefining and enhancements Evolution

The PSP0 Process Demonstrates the use of a defined process in writing small programs Incorporates basic measurement into a student’s software development process Requires minimal changes to a student’s personal practices

Measurement in a Defined Process Measured historical data is needed for effective planning. Measurement tells when and how process tasks are carried out. Measured data is used to evaluate and improve a process. The PSP uses three types of measures. effort size defects

Effort Measurement The PSP measures effort as time in minutes. appropriate for small programs easy to measure precisely Students keeps accurate records of time spent on each programming task. Interruption time is recorded and subtracted from time spent on development tasks.

Size Measurement Size data is used in estimating development time and the expected number of defects. There are a number of criteria for good size measures. has good correlation with effort has a precise definition can be counted automatically is suitable for planning is sensitive to language, design, and development method A lines of code (LOC) measure satisfies most of the criteria for good size measures. The PSP uses LOC for measuring size.

CMU 1994 Data Correlation Between Size and Effort

Defect Measurement A PSP defect is something that must be changed to correct an error made in a software artifact (design, code, etc.) classified according to a defect type standard For each defect, students record the defect type, a description of the defect, and the fix time. All changes related to a single error are counted as one defect. Fix time is recorded in the phase in which the defect is removed (e.g, compile or test).

PSP0 Process Finished product Development Planning Postmortem Design Code Compile Test Requirements Plan summary Process scripts Time and defect logs The PSP0 Process Flow

Tracking Your Time As the first step, you need to know what you currently do by tracking time spend on each of the following categories Attend class Read textbook Write code for lab and/or program assignments Prepare for quizzes and tests Use the time recording log for activities associated with this class The form can be found under our class folder on blackhawk

An Example Student Y first entered her name and the date she started to fill in the form. She also entered the instructors name and the course name or number. When she started to keep time records on September 9, she recorded date on the top line in the body of the form and made the first entry at the left Her first activity was to attend a CS1 class lecture at 9:00 AM. The class lasted until 9:50, on total of 50 minutes. The student then entered 9:00 in the Start column, 9:50 in the Stop column, and the 50 minutes duration in the Delta Time column. At right, she entered the name of the activity in the column labeled Activity. Finally, in the Comments column, she noted what she was doing. As Student Y continued through the day, she noted her other activities for the CS course in the time log.

Filling out the Form

Handling Interruptions The way interruptions are handled with the Time Recording Log is to note them In the column labeled interruption Time. As in our example, Student Y started her homework at 11:06 on the 10th and stopped at 12:19. During this period, she was interrupted twice, once for 6 minutes and once for 5. The net time she spent on her homework is thus 73 minutes less 11 minutes of interruption time, or a total of 62 minutes. Student Y not only noted these times in the Time Recording Log; she also briefly described the interruptions in the comments column.