WEBVTT 1 00:00:28.890 --> 00:00:30.420 William Cheng: Hello. Is it working now. 2 00:00:31.650 --> 00:00:32.220 Andrew Strimaitis: Can you hear me. 3 00:00:32.550 --> 00:00:35.970 William Cheng: Yes, I can hear you now. Sorry about it. I think something's wrong, my end. 4 00:00:36.510 --> 00:00:41.430 Andrew Strimaitis: That's fine. I'm okay so lecture 12 we 5 00:00:42.840 --> 00:00:45.600 Andrew Strimaitis: Talked about the exams at one point. 6 00:00:46.170 --> 00:00:50.880 Andrew Strimaitis: Yes. And you mentioned that it's going to be 7 00:00:52.020 --> 00:00:53.580 Andrew Strimaitis: chapter one to chapter four. 8 00:00:53.940 --> 00:01:00.810 Andrew Strimaitis: Yes. Um, is that, including all the stuff about Chapter one, because I know we jumped around a lot with Chapter one. 9 00:01:01.200 --> 00:01:03.900 William Cheng: Yeah, so only the stuff that has been covering lectures. 10 00:01:05.730 --> 00:01:08.730 Andrew Strimaitis: Right. But I know lecture wise. 11 00:01:09.960 --> 00:01:18.600 Andrew Strimaitis: I don't know if we did all of chapter one. By now, but I know that we started with chapter one and then we went on to other chapters and then eventually came back to chapter one with files. 12 00:01:19.620 --> 00:01:23.160 Andrew Strimaitis: So I'm wondering if all of chapter one, then, is is covered in this or just part 13 00:01:23.160 --> 00:01:23.430 Andrew Strimaitis: Of it. 14 00:01:25.230 --> 00:01:28.350 William Cheng: So I think all of chapter one is covered 15 00:01:30.120 --> 00:01:30.450 Andrew Strimaitis: Okay. 16 00:01:31.380 --> 00:01:45.690 William Cheng: And all of Chapter two is covered. Chapter three. So what happened is that today, I'm going to post the sort of a sort of an itemized you know thing that is covered by the by the exam on the class web page. 17 00:01:46.500 --> 00:01:59.580 William Cheng: So you'll see a complete list. So I think, chapter three, the dynamic Lincoln and loading is skipped and Chapter four, only the first two parts are included by the first one is a simple system and the second one is 18 00:02:00.720 --> 00:02:02.310 William Cheng: Storage system, something like that. 19 00:02:05.130 --> 00:02:05.550 Andrew Strimaitis: Okay. 20 00:02:05.850 --> 00:02:11.700 William Cheng: Yeah, so I thought I will have a, you know, I guess sort of a more detailed list posted today. Okay. 21 00:02:11.940 --> 00:02:16.350 Andrew Strimaitis: Um, and I was hoping you could explain soft links, a little more 22 00:02:18.060 --> 00:02:23.130 William Cheng: YEAH, SO SO SOFT link or symbolic link. So it's a special kind of file. 23 00:02:24.330 --> 00:02:28.350 William Cheng: So, and this file sort of contain another you know found name or directory name. 24 00:02:29.010 --> 00:02:40.440 William Cheng: So will you we performed path name resolution when you hit one of the soft link, you'd have to save the contacts and then go traverse the soft link and then we're done. You come back and continue where you left off. 25 00:02:41.880 --> 00:02:45.060 Andrew Strimaitis: OK. And then, as opposed to hard links which are 26 00:02:46.260 --> 00:02:46.860 Andrew Strimaitis: Um, 27 00:02:48.840 --> 00:02:53.070 William Cheng: Yeah, so, so for Harley, you, you, you have to point it to a file. 28 00:02:53.700 --> 00:03:00.630 William Cheng: Right. And why did you create the Harlan, you don't really know you know was, what was that link their first or the previous link their first there. They all look the same. 29 00:03:01.740 --> 00:03:07.860 William Cheng: So they just sort of break the director hierarchy. So now you have multiple directory that can sort of pointed the same file. 30 00:03:10.590 --> 00:03:10.920 Andrew Strimaitis: Okay. 31 00:03:11.700 --> 00:03:12.000 Okay. 32 00:03:43.950 --> 00:03:46.650 Andrew Strimaitis: Also for the permissions example. 33 00:03:46.860 --> 00:03:54.090 Andrew Strimaitis: Okay. Um, I noticed. So let's say slide I don't know 30 to 30 for any of those slides. 34 00:03:59.850 --> 00:04:04.620 Andrew Strimaitis: Yeah, so I I was trying to understand the meaning of the red dash 35 00:04:05.790 --> 00:04:12.750 William Cheng: Right. So the red dash over here. So this is the answer py. Right. The answer part, the red dash tell you exactly where permission was denied. 36 00:04:13.350 --> 00:04:20.940 Andrew Strimaitis: Okay, and then I know like two slides later the red dash has moved to a different line. 37 00:04:21.780 --> 00:04:32.790 William Cheng: Right so so permission is granted at the directory level right so we hit this directory level permission was granted. And then when you go to the file that the slash x which is right here. Then permission was denied. 38 00:04:33.360 --> 00:04:33.690 Hmm. 39 00:04:36.750 --> 00:04:43.620 William Cheng: So will you try to traverse the path. You can get denied you know earlier in the directory path or it could be at the final file. 40 00:04:44.520 --> 00:04:44.910 Okay. 41 00:04:48.780 --> 00:04:57.780 William Cheng: Yeah. So in order for you to have permission to access a file, you have to, you know, all the directory you know all the sub directory permissions and then finally the file. You also have to have permission. 42 00:05:34.920 --> 00:05:36.120 William Cheng: Anyone else has a 43 00:05:37.200 --> 00:05:37.800 William Cheng: Question. 44 00:05:51.930 --> 00:05:55.290 Andrew Strimaitis: I might be able to come up. Come up with a couple more questions. 45 00:05:55.620 --> 00:06:06.540 William Cheng: Okay, yeah. So for the permissions, who also look at your warm up one and two grading guidelines and then sort of tried to do a directory listing and find out you know why they permission was denied. 46 00:06:09.060 --> 00:06:09.420 Andrew Strimaitis: Hmm. 47 00:06:52.890 --> 00:06:54.660 Andrew Strimaitis: Okay, so for the disk map. 48 00:06:55.590 --> 00:06:56.040 William Cheng: Okay. 49 00:06:56.460 --> 00:06:58.320 Andrew Strimaitis: Which is slide 64 50 00:07:04.650 --> 00:07:04.890 William Cheng: Yep. 51 00:07:06.150 --> 00:07:10.860 Andrew Strimaitis: What is the purpose of pointer 12 with the triple can direct pointer. 52 00:07:11.340 --> 00:07:16.440 William Cheng: Yeah, if you want to get beyond 64 megabytes your, you know, require a really big file. 53 00:07:17.760 --> 00:07:21.060 William Cheng: So over here, right, right here. 54 00:07:23.400 --> 00:07:34.470 William Cheng: Right, because with the 11th pointer, you can only get to 64 megabytes plus 266 kilobytes. So if you fall is bigger than that you are you're required to use the last point here. 55 00:07:36.810 --> 00:07:43.740 William Cheng: Why, because if you just add up all the, you know, so assuming that each one of these things is one kilobytes. If you add them all to size. This is all you're going to get 56 00:07:45.270 --> 00:07:45.660 Andrew Strimaitis: Okay. 57 00:08:34.140 --> 00:08:35.550 Andrew Strimaitis: Does anybody else have a question. 58 00:08:40.380 --> 00:08:41.130 Hardik Mahipal Surana: No, not really. 59 00:08:43.140 --> 00:08:47.100 William Cheng: Okay, so. So is it okay if I just, you know, shut it down and stop recording 60 00:08:49.590 --> 00:08:50.190 Andrew Strimaitis: I guess. 61 00:08:50.730 --> 00:08:51.750 Andrew Strimaitis: I think I'm good here. 62 00:08:52.110 --> 00:08:54.420 William Cheng: Alrighty, feel free to come to office hours today. Okay. 63 00:08:55.050 --> 00:08:56.400 Andrew Strimaitis: Okay, thank you.