io/file-descriptors: Add testing suggestion for each task.

Suggested students to test manually each task before using
'tests/checher.sh', for a better understanding of the concept.

Added `lab9.md` that instructs students to download the arhive
or use GitHub.

Changed config.yaml to add `lab9.md` to the archive.

Signed-off-by: Matei Stanuca <[email protected]>

Author: mateistanuca1

chapters/io/file-descriptors/drills/tasks/buffering/README.md

@@ -21,6 +21,9 @@ We'll checkout how effective buffering is in `libc` and then we'll do it ourselv
    Wrote 1048576 bytes to test-file.txt in 38 ms
    ```
 
+   If possible, try to manually test your implementation.
+   Use `./checker.sh` only when you are sure of your result.
+
    Buffering achieves dramatic performance gains, reducing read times by **98%** and write times by **99.8%** in this example!
    This demonstrates the power of buffering, even though it’s an extreme case.
 

chapters/io/file-descriptors/drills/tasks/mmap_cp/README.md

@@ -16,6 +16,11 @@ make: Nothing to be done for 'all'.
 Test PASSED (File copies are identical)
 ```
 
+To test your implementation, navigate to the `mmap_cp/support/src` folder.
+Run `make` to compile the code and test it manually with files generated by you.
+
+When you think your code is correct, go to `mmap_cp/support/test` and run `checker.sh` to validate your solution.
+
 1. Open `mmap_cp.c` and complete the TODOs to map the files in memory and copy the contents.
    Do not forget to clean up by unmapping and closing the files.
 

chapters/io/file-descriptors/drills/tasks/my-cat/README.md

@@ -18,6 +18,11 @@ Good job!
 ----------------------------------------
 ```
 
+To test your implementation, navigate to the `mmap_cp/support/src` folder.
+Run `make` to compile the code and test it manually with files generated by you.
+
+When you think your code is correct, go to `mmap_cp/support/test` and run `checker.sh` to validate your solution.
+
 1. Implement `rread()` wrapper over `read()`.
 
    `read()` system call does not guarantee that it will read the requested number of bytes in a single call.

chapters/io/ipc/drills/tasks/anon-pipes/README.md

@@ -15,6 +15,11 @@ Test for short string ........... PASSED
 Test for long string  ........... PASSED
 ```
 
+To test your implementation, navigate to the `mmap_cp/support/src` folder.
+Run `make` to compile the code and test it manually with files generated by you.
+
+When you think your code is correct, go to `mmap_cp/support/test` and run `checker.sh` to validate your solution.
+
 1. Use the [`pipe()` syscall](https://man7.org/linux/man-pages/man7/pipe.7.html) to create the pipe.
    Remember, the first file descriptor (`fds[0]`) is the read end, and the second (`fds[1]`) is the write end, similar to how `stdin` and `stdout` are represented by file descriptors `0` and `1`.
 

chapters/io/overview/reading/lab9.md

@@ -0,0 +1 @@
+The contents of the lab are located in the [lab archive](https://github.com/cs-pub-ro/operating-systems/raw/refs/heads/lab-archives/Lab_9_File_Descriptors.zip) and in the [GitHub repository](https://github.com/cs-pub-ro/operating-systems).

config.yaml

@@ -126,6 +126,7 @@ lab_structure:
   - title: Lab 9 - File Descriptors
     filename: lab9.md
     content:
+      - reading/lab9.md
       - tasks/my-cat.md
       - tasks/mmap_cp.md
       - tasks/anon-pipes.md