PUBLIC ANSWERS TO EXERCISES Chapter 1. Software and Software Engineering El.1 p 5 Classifying software a)*Custom; real-time c)Generic; real-time(but soft real-time El.2 p. 10 Stakeholder reactions to situations particular type of work. On the other hand, he or she may be relieved about not being put out of wort i a)*. The user may be disappointed, since he or she might be looking forward to no longer having to do ince many people believe that software systems are easy to develop; they underestimate the complexity of tasks that are to be automated. The customer might consult some other software engineer to obtain a second opinion The developers will probably move on to other work The development managers may be disappointed at not having the opportunity to do further work on the project E1.3 p 12 Prioritizing quality attributes a)*Reliability will be paramount for the spacecraft software. It would be sad if the spacecraft did not make it into orbit after all that time, although no lives would be lost. Efficiency might be important since processors from 20 years earlier are far slower than today's devices. Usability will likely not be an issue since the software will run autonomously and report any feedback to experts; furthermore the software cannot be interactive since it takes considerable time to send signals to and from Pluto at the speed of light Maintainability is also likely to be a minimal concern since this software is likely to only be used once However, there remains the possibility that the software could be used on other systems, or will need to be changed as last-minute bugs are fixed c)* Maintainability will likely be the most important concern since data processing software tends to evolve Reliability will also be of considerable importance: Bill printing must be accurate, since it can be costly to ify mistakes. Usability of the bills themselves will be important because ordinary people have to derstand them Efficiency should not be a concern THESE ANSWERS SUPPORT THE BOOK OBJECT ORIENTED SOFTWARE ENGINEERINGPUBLI C A NSW ERS T O EX E RCISE S PA2 T HE SEAN SW E RS SU PPORTT HEBO OK O BJ ECT O RI E NTEDSO FTW AR E E NG INE ER ING : Chapt er 1. Soft w ar e and Soft war e Engineer ing E 1.1 p. 5 Classify ing software . a )*Custom; re a l- time. c )*G ener ic; r e al-time( but soft re al- time ) . E 1.2 p. 10 Stak e holde r re actions to situations. a )*• T he use r ma y be disappointed, sinc e he orshe might belooking f or wa r d to no longer ha ving to do this par tic ulartypeofw ork. O n theothe r ha nd, heor shema y bere lie ve d a bout not being put out ofw or k. • T he c ustom er ma y be disappointed at not be ing a ble to save mone y; he or she ma y also be surpr ised, since ma ny pe ople be lie ve that softw ar e syste ms ar e e asy to develop; they unde re stima te the c omple xity of ta sks tha t a reto be a utoma te d. The c ustomermight c onsultsome other softwa r e enginee r to obtain asec ond opinion. • T he develope rs will pr oba bly move on to othe rw or k. • T he de ve lopme nt m anage rs ma y be disappointed at not ha ving the opportunity to do f ur the r w or k on thepr ojec t. E 1.3 p. 12 Prioritizing qualityattribute s a )*R eliabilit y will bepa ra mount f or thespa c ec ra f t sof tw ar e . It would be sad ifthe spac e cr af t did not make it into orbit af te r a ll that time , a lthough no live s w ould be lost. Eff ic iency might be impor tant since proce ssors fr om 20 ye ar s e ar lie r ar e f ar slow e r tha n today’s de vic es. U sabilit y will like ly not be a n issue since the sof tw a re w ill r un autonomously and r epor t a ny fe edbac k to exper ts; f ur the rmore the sof tw ar e c annot be inter a ctivesinc e it ta ke s c onsider a ble time to se nd signa ls to a nd fr om Pluto a t thespee d of light. M aint ainability is a lso like ly to be a minima l c onc er n since this softw ar e is likely to only be used once . H ow eve r, ther e r emains thepossibility that the sof tw ar ec ould beused on othe r syste ms, orw ill nee d to be c ha nge d as la st- minute bugs ar ef ixe d. c )*M aint ainability will like ly be the most impor tant c once r n since da tapr oc essing sof tw a rete nds to evolve. R eliabilit y will also beofc onsider a ble impor tance : Bill printing must be a c cura te, sinc e it ca n be c ostly to r ec tif y mista ke s. U sabilit y of the bills themse lve s w ill be impor ta nt be c ause or dinar y people have to under sta nd them. Eff ic iency should not be ac onc er n