Discussion Sections - CSCI 402, Fall 2020, All Sections

In the slides and videos section below, I will post slides and pre-recorded discussion section videos before 6PM on the day before the live discussion section. In a discussion section video, I will primarily present information regrading up-coming programming assignments. I will also post live discussion section videos there.

Each live discussion section is conducted by a TA. Below is a list showing which TA is responsible for which discussion section:

Fri 10:00am - 10:50am in (online) Ben Yan / Zhuojin Li
Fri 11:00am - 11:50am in (online) (cancelled starting with Week 2)
Fri 12:00pm - 12:50pm in (online) Zhuojin Li

During a live discussion section, the TA will answer questions about the pre-recorded video and answer your questions about programming assignments. If you have a particular topic that you would like the TA to discuss in class (including stuff like something covered in lectures that you would like the TA to explain further), you should send e-mail to the TA before 6PM on Thursday. The TA will try his/her best to cover such requests.

Please note that programming assignments are due on Fridays. Since you are expected to have finished the an assignment before its due date, on the due date of a programming assignment, the TA will be introducint the next programming assignment and that takes priority over the current assignment. If there is time left, the TA can discuss the current assignment.

To download all the PDF files below in one command (so you can study for exams), do the following inside a terminal in Ubuntu 16.04:

    wget -r -l 1 --user=USERID --password=PASSWORD http://merlot.usc.edu/cs402-f20/discussions.html

where USERID and PASSWORD are the user ID and password used to access protected content from our class web site. But please note that the lecture slides can change at any time without notice. Therefore, it's a good idea to re-run the above command often to synchroniza your copy with the server!

When Should I Watch These Videos?

The discussion section videos are there to help you with programming assignments. Therefore, it's advisable that you watch the discussion section videos first before you start writing a lot of code! Even though the date of a discussion section may be in the future, if a video is available early, it's useful to check it out as early as possible! This can save you from having to rewrite a lot of code.

It's possible that you may get confused when you watch a discussion section video because you are not familiar enough with the spec and what you are supposed to do. But that's okay! It's important that you have seen the material so that when you are going in the wrong direction, you may be able to stop and review the material again before proceeding. As I have mentioned many times, if you are confused about anything, don't hesitate to ask me! I'm here to help and I cannot help you if you don't ask questions!

Slides and Videos

(Please note that access to discussion slides and videos are restricted.)

Week 1 (PDF) (6-up PDF) (Aug 21, 2020) - gdb, warmup #1
- video (part 1 of 2) - 40 minutes
- video (part 2 of 2) - 36 minutes
- 10am live discussion section - 14 minutes
- 11am live discussion section - 11 minutes
- 12pm live discussion section - 13 minutes
Week 2 (PDF) (6-up PDF) (Aug 28, 2020) - parsing text input in C, Unix/Linux commands, introduction to warmup #2
- video (part 1 of 2) - 50 minutes
- video (part 2 of 2) - 25 minutes
- 10am live discussion section - 4 minutes
- 12pm live discussion section - 13 minutes
Week 3 (PDF) (6-up PDF) (Sep 4, 2020) - warmup #2
- video (part 1 of 2) - 43 minutes
- video (part 2 of 2) - 22 minutes
- 10am live discussion section - 21 minutes
- 12pm live discussion section - 16 minutes
Week 4 (PDF) (6-up PDF) (Sep 11, 2020) - warmup #2 (catching SIGINT and pthread cancellation), introduction to kernel assignments
- video (part 1 of 2) - 40 minutes
- video (part 2 of 2) - 38 minutes
- 10am live discussion section - 8 minutes
- 12pm live discussion section - 13 minutes
Week 5 (PDF) (6-up PDF) (Sep 18, 2020) - kernel 1, kmain.c
- video (part 1 of 1) - 52 minutes
- 10am live discussion section - 7 minutes
- 12pm live discussion section - 13 minutes
Week 6 (PDF) (6-up PDF) (Sep 25, 2020) - faber_test.c, kernel 1 FAQ
- video (part 1 of 1) - 52 minutes
- 10am live discussion section - 12 minutes
- 12pm live discussion section - 15 minutes
Week 7 (PDF) (6-up PDF) (Oct 2, 2020) - introduction to kernel 2
- video (part 1 of 1) - 52 minutes
- 10am live discussion section - 6 minutes
- 12pm live discussion section - 13 minutes
Week 8 (TXT) (Oct 9, 2020) - kernel 2 polymorphism, ramfs.c vfstest.c, faber_fs_test
- video (part 1 of 1) - 52 minutes
- 10am live discussion section - 6 minutes
- 12pm live discussion section - 11 minutes
Week 9 (PDF) (6-up PDF) (Oct 16, 2020) - introduction to kernel 3, the elf32 loader
- video (part 1 of 1) - 60 minutes
- 10am live discussion section - 6 minutes
- 12pm live discussion section - 11 minutes
Week 10 (PDF) (6-up PDF) (Oct 23, 2020) - address space implementation (vmarea, mmobj, pframe, page table), introduction to page fault handling
- video (part 1 of 1) - 57 minutes
- 10am live discussion section - 6 minutes
- 12pm live discussion section - 15 minutes
Week 11 (TXT) (Oct 30, 2020) - objdump, page fault handling, kernel 3 FAQ
- video (part 1 of 1) - 52 minutes
- 10am live discussion section - 9 minutes
- 12pm live discussion section - 18 minutes
Week 12 (TXT) (Nov 6, 2020) - fork(), user space shell, remaining user space programs
- video (part 1 of 1) - 52 minutes
- 10am live discussion section - 8 minutes
- 12pm live discussion section - 12 minutes
Week 13 (Nov 13, 2020) - no discussion section this week

Tentative Slides

The following are tentative discussion section slides (in PDF format) for this semester. Please note that the source code below is for the purpose of discussions and may not be identical to the code in your assignments. It would be a really bad idea (because you can lose a lot of points) to replace the code in your assignments with the code here!

Week 1 (PDF) (6-up PDF) (8/21) - gdb, warmup #1
Week 2 (PDF) (6-up PDF) (8/28) - parsing text input in C, Unix/Linux commands, introduction to warmup #2
Week 3 (PDF) (6-up PDF) (9/4) - warmup #2
Code in slides:
Week 4 (PDF) (6-up PDF) (9/11) - warmup #2 (catching SIGINT and pthread cancellation), introduction to kernel assignments
Code in slides:
Week 5 (PDF) (6-up PDF) - kernel 1, kmain.c
Week 6 (PDF) (6-up PDF) - faber_test.c, kernel 1 FAQ
Week 7 (PDF) (6-up PDF) - introduction to kernel 2
Code:
- namev.c (path name resolution code)
Week 8 (TXT) - kernel 2 polymorphism, ramfs.c vfstest.c, faber_fs_test
Code:
- vfs.c
- vnode.c
- ramfs.c (also look for any "_ops_t" in "kernel/include/fs/*.h", "kernel/fs/*.c" and "kernel/fs/ramfs/*.c")
- vfs_syscall.c
- vfstest.c
- faber_fs_test.c
Week 9 (PDF) (6-up PDF) - introduction to kernel 3, the elf32 loader
Code (kernel):
- elf32.c - the elf32 loader
- access.c
- exec.c
Week 10 (PDF) (6-up PDF) - address space implementation (vmarea, mmobj, pframe, page table), introduction to page fault handling
Code (kernel):
- vn_mmobj_ops.c - code for the mmobj inside a vnode
Code (user):
- hello.c
- syscall.c (in the libc user space library)

Week 11 (TXT) - objdump, page fault handling, kernel 3 FAQ

Code (user):

hello.c
syscall.c (in the libc user space library)

Kernel 3 FAQ:

Useful Linux commands:

    objdump --disassemble --section=".text" user/usr/bin/hello.exec
    objdump --disassemble --section=".text" -S user/usr/bin/hello.exec
    objdump --headers user/usr/bin/hello.exec
    xxd -g 1 user/usr/bin/hello.exec

Useful GDB commands:

    add-symbol-file user/usr/bin/hello.exec 0x08048094
    b __libc_static_entry
    b main
    b *0x12345678
    layout asm
    layout next
    si
    info registers
    kernel info vmmap_mapping_info curproc->p_vmmap

Week 12 (TXT) - fork(), user space shell, remaining user space programs
Code (user):
Kernel 3 FAQ:
Week 13 - (no discussion section this week)