cp/usth/ICT2.7/P1L4 Version Control Subtitles/9 - Two Main Types of VCS - lang_en_vs5.srt

1
00:00:00,160 --> 00:00:01,970
Something else I want to mention is that there

2
00:00:01,970 --> 00:00:05,460
are many different version control systems but we can classify

3
00:00:05,460 --> 00:00:09,250
them normally in two main types: centralized VCS's and

4
00:00:09,250 --> 00:00:13,230
decentralized VCS's. So what is the difference between these two?

5
00:00:13,230 --> 00:00:16,750
Let's use again our friends Janet and Brett.

6
00:00:16,750 --> 00:00:19,510
In the case of a centralized version control system

7
00:00:19,510 --> 00:00:22,290
there is a single centralized, as the name says,

8
00:00:22,290 --> 00:00:25,230
repository. On which they are commiting their files. So when

9
00:00:25,230 --> 00:00:27,290
Janet commits a file. The file will go from

10
00:00:27,290 --> 00:00:30,390
her local working directory to the repository, and the same

11
00:00:30,390 --> 00:00:33,520
will happen to Brett. The decentralized system is a little

12
00:00:33,520 --> 00:00:37,310
more interesting because in this case, they will both have

13
00:00:37,310 --> 00:00:40,790
sort of a local repository in which they can commit

14
00:00:40,790 --> 00:00:43,970
their changes. So they can commit changes without the other

15
00:00:43,970 --> 00:00:47,940
users of the VCS being able to see these changes.

16
00:00:47,940 --> 00:00:50,300
And when they're happy with the version. And when they're

17
00:00:50,300 --> 00:00:53,900
ready to release the version, they can push it to a central

18
00:00:53,900 --> 00:00:56,840
repository. And at that point, it will become available to the other

19
00:00:56,840 --> 00:01:01,100
users of the repository. To the other users of the VCS. There

20
00:01:01,100 --> 00:01:02,870
are several advantages in a distributive

21
00:01:02,870 --> 00:01:04,300
system. I'm just going to mention a few,

22
00:01:04,300 --> 00:01:07,520
because there are really many. One is the fact of having this

23
00:01:07,520 --> 00:01:10,570
local version. If you used VCS before, I'm sure you've been in

24
00:01:10,570 --> 00:01:13,280
the situation in which you want to kind of take a snapshot

25
00:01:13,280 --> 00:01:15,820
of what you have. But you don't want that snapshot to be available

26
00:01:15,820 --> 00:01:18,200
to the other users. Because it's still not ready to be

27
00:01:18,200 --> 00:01:21,240
released, to be looked up. If you're using a centralized system,

28
00:01:21,240 --> 00:01:23,140
there's really no way you can do that, unless you make

29
00:01:23,140 --> 00:01:25,150
a local copy, which is something we said you don't want

30
00:01:25,150 --> 00:01:28,625
to do. With a distributor, with a decentralized VCS you can

31
00:01:28,625 --> 00:01:32,444
commit your local changes here, in your local repository, and you

32
00:01:32,444 --> 00:01:37,030
can push them to the central repository only when you're ready.

33
00:01:37,030 --> 00:01:40,870
Another big advantage, is that you can use multiple remote repository.

34
00:01:40,870 --> 00:01:43,210
In fact, centralized is not the right name for this

35
00:01:43,210 --> 00:01:45,980
one. This is just a remote repository, and I can have

36
00:01:45,980 --> 00:01:48,910
more than one. For example, Brad might want to push

37
00:01:48,910 --> 00:01:52,150
to another remote repository. As well. For instance, this could be

38
00:01:52,150 --> 00:01:55,940
a repository where the files are accessible for wider distribution.

39
00:01:55,940 --> 00:01:59,620
Imagine developing a software system in which a team is sharing

40
00:01:59,620 --> 00:02:02,930
internal versions, and then only some of these versions are actually

41
00:02:02,930 --> 00:02:06,080
pushed to the repository that is seeable to the whole world.