From b2d80610db6beda38573890ed169815e495bc663 Mon Sep 17 00:00:00 2001 From: Nguyễn Gia Phong Date: Sun, 24 May 2020 16:34:31 +0700 Subject: [usth/ICT2.7] Engineer software --- .../12 - Spiral Process - lang_en_vs4.srt | 191 +++++++++++++++++++++ 1 file changed, 191 insertions(+) create mode 100644 usth/ICT2.7/P1L2 Life Cycle Models Subtitles/12 - Spiral Process - lang_en_vs4.srt (limited to 'usth/ICT2.7/P1L2 Life Cycle Models Subtitles/12 - Spiral Process - lang_en_vs4.srt') diff --git a/usth/ICT2.7/P1L2 Life Cycle Models Subtitles/12 - Spiral Process - lang_en_vs4.srt b/usth/ICT2.7/P1L2 Life Cycle Models Subtitles/12 - Spiral Process - lang_en_vs4.srt new file mode 100644 index 0000000..2d0cdf9 --- /dev/null +++ b/usth/ICT2.7/P1L2 Life Cycle Models Subtitles/12 - Spiral Process - lang_en_vs4.srt @@ -0,0 +1,191 @@ +1 +00:00:00,120 --> 00:00:02,600 +The next model that we will discuss is the spiral + +2 +00:00:02,600 --> 00:00:05,630 +model, which was first described by Barry Boehm, which is + +3 +00:00:05,630 --> 00:00:08,010 +the professor that we interviewed at the beginning of this + +4 +00:00:08,010 --> 00:00:12,240 +lesson. In his paper from 1986 that was entitled A Spiral + +5 +00:00:12,240 --> 00:00:15,730 +Model of Software Development and Enhancement. And one of the + +6 +00:00:15,730 --> 00:00:18,520 +main characteristics of that paper is that it was describing the + +7 +00:00:18,520 --> 00:00:21,670 +spiral model using a diagram, which is the one that + +8 +00:00:21,670 --> 00:00:25,130 +I'm showing you here, and this diagram has become very very + +9 +00:00:25,130 --> 00:00:27,950 +popular, and you probably saw it either in this + +10 +00:00:27,950 --> 00:00:30,400 +form or one of the many variations of the + +11 +00:00:30,400 --> 00:00:32,680 +diagram. So I'm not going to discuss all of + +12 +00:00:32,680 --> 00:00:34,770 +the details of the spiral model, but I just want to + +13 +00:00:34,770 --> 00:00:37,510 +give you an idea of its main characteristics. The + +14 +00:00:37,510 --> 00:00:41,580 +spiral model is an incremental risk-oriented lifecycle model that has + +15 +00:00:41,580 --> 00:00:46,330 +four main phases listed here: determine objectives, identify and + +16 +00:00:46,330 --> 00:00:51,180 +resolve risks, development and tests, and plan the next iteration. + +17 +00:00:51,180 --> 00:00:53,690 +A software project will go through these four phases in + +18 +00:00:53,690 --> 00:00:57,020 +an iterative way. In the first phase, the requirements will + +19 +00:00:57,020 --> 00:00:59,470 +be gathered. In the second phase, the risks and the + +20 +00:00:59,470 --> 00:01:04,010 +alternate solutions will be identified, and a prototype will be produced. + +21 +00:01:04,010 --> 00:01:06,190 +Software and tests for the software are produced in the + +22 +00:01:06,190 --> 00:01:09,210 +development and test phase, which is the third step of the + +23 +00:01:09,210 --> 00:01:12,830 +process. Finally, in the fourth phase, the output of the + +24 +00:01:12,830 --> 00:01:16,880 +project, so far, is evaluated, and the next iteration is planned. + +25 +00:01:16,880 --> 00:01:19,960 +So basically, what the spiral process prescribes is a + +26 +00:01:19,960 --> 00:01:23,262 +way of developing software by going through these phases in + +27 +00:01:23,262 --> 00:01:26,020 +an iterative way, in which we learn more and more + +28 +00:01:26,020 --> 00:01:29,420 +of the software, we identify more and more, and account + +29 +00:01:29,420 --> 00:01:32,250 +for, more and more risks and we go more + +30 +00:01:32,250 --> 00:01:36,000 +and more towards our final solution, our final release. There + +31 +00:01:36,000 --> 00:01:38,930 +are several advantages of using a spiral model. The first + +32 +00:01:38,930 --> 00:01:41,930 +one is that the extensive risk analysis does reduce the + +33 +00:01:41,930 --> 00:01:44,140 +chances of the project to fail. So there is a + +34 +00:01:44,140 --> 00:01:48,300 +risk reduction advantage. The second advantage is that functionality can be + +35 +00:01:48,300 --> 00:01:51,190 +added at a later phase because of the iterative nature of + +36 +00:01:51,190 --> 00:01:55,175 +the process. And finally, software is produced early in the software + +37 +00:01:55,175 --> 00:01:58,260 +lifecycle. So, at any iteration, we have something to show + +38 +00:01:58,260 --> 00:02:01,300 +for our development. We don't wait until the end before producing + +39 +00:02:01,300 --> 00:02:03,790 +something. And then of course there's also the advantage that we + +40 +00:02:03,790 --> 00:02:07,190 +can get early feedback from the customer about what we produced. + +41 +00:02:07,190 --> 00:02:09,000 +The main disadvantages on the other hand of + +42 +00:02:09,000 --> 00:02:11,870 +the spiral model, are that the risk analysis requires + +43 +00:02:11,870 --> 00:02:16,560 +a highly specific expertise. And unfortunately, the whole success + +44 +00:02:16,560 --> 00:02:19,260 +of the process is highly dependent on risk analysis. + +45 +00:02:19,260 --> 00:02:21,580 +So risk analysis has to be done right. + +46 +00:02:21,580 --> 00:02:24,510 +And finally the spiral model is way more complex + +47 +00:02:24,510 --> 00:02:27,180 +than other models, like for example, the water fall + +48 +00:02:27,180 --> 00:02:29,760 +model. And therefore it can be costly to implement. -- cgit 1.4.1