Fix FAT12 Filesystem Driver

[BrightCat14]

The current FAT12 driver in OpenDOS is not working correctly:

• It does not display the contents of the root directory or subdirectories.
• It is unclear whether it can read or write files properly.

Goal:
Fix the FAT12 driver so that files can be safely read, written, and listed.

Tasks:

1. Verify reading of the root directory and subdirectories.
2. Fix reading/writing of files to ensure data integrity.
3. Add simple test programs: create a file, write text, read it back.

Why this is important:

• A working FAT12 driver is essential for future features:

  • Executing user programs
  • Basic file utilities (ls, cat, etc.)

Who can do this:

• Intermediate contributors familiar with C and low-level I/O.

[f4ni]

Hello @BrightCat14 I want to understand and learn more about this project so I would need your guidance to help me understand each and everything about this. For that if I work on this feature as well that would be helpful for me. Thanks

[BrightCat14]

Hi @fani1016, thanks for your interest!

This is a core feature, so it’s a great opportunity to learn about OpenDOS internals. I’ll guide you through the structure and help with any questions you have while working on the FAT12 driver.

Start by exploring how the current driver reads directories and files, and we can plan step by step how to fix it.

Don’t worry about making changes—take your time, do everything gradually, and there’s no rush. You’re free to experiment and learn at your own pace.

[f4ni]

Thanks, I'll start looking into it

[BrightCat14]

Hello @fani1016, any updates on this issue?

[f4ni]

Hi, not yet, I'll look into into it on this weekend

[f4ni]

Hi, I started looking into it and after adding a few prints, I found these issues in current implementation

[BrightCat14]

Hi, I started looking into it and after adding a few prints, I found these issues in current implementation

Hi @fani1016, I didn’t even notice that
You’re right – the script makes a FAT32 partition but then formats it as FAT12.
What we actually need is to make them consistent (either set the partition type to FAT12, or specify the correct type code, 0x01).
(this script was taken from my other projects, that’s why there is such confusion, and I forgot to adjust it for FAT12)
Thanks for pointing it out!