Booting from Floppy

[isoux]

Hello there and thank you for wonderful work!

I propose here what I wanted to do for myself. Namely, to boot the system from a floppy disk.

There are several reasons, but one of the most important is that someone else would like it and that my machine (from linked video) will not boot from a USB stick with your image because the bios has some protection and I cannot remove it ...

I forked BareMetal-OS and Pure64, and I made some small changes and everything works as I wanted except that there is no filesystem on the disk as it is not available from your USB stick image either...

I'm planning to make a simple file system for floppy disks, but as far as this OS is concerned, on system boot the entire image of the floppy would be loaded into RAM from protected mode, and from there the FS would be used, and at the end of the working, the entire image can be burn to a floppy disk. Because what is 1.5 megabytes for the available gigabytes now.
If you download my repository and run baremetal.sh you will also get a floppy.img that you can try.
This image do not fully work on QEMU & BOCHS but work perfectly on real machine!

I'm writing all this as an idea and I didn't want to start a pull request if you don't think this is worth it and I didn't want to force this either?

[IanSeyler]

This is great! Please create pull requests for your changes and I will merge them.

Loading a file system to memory is a good idea for floppy/USB booting.

[isoux]

Great!

I think it's good to do pull requests on master branches, it's simpler than creating a new branch, for example floppy?

[isoux]

I did it, please fix grammar mistakes if there are and things with indentation tabs and spaces ...

[isoux]

I will have to do another pull request.
Lines of code in baremetal.sh

# Create Floppy image
dd if=/dev/zero of=floppy.img count=2880 bs=512 > /dev/null 2>&1

It should be in the baremetal_build function. Otherwise, a proper 1.5 Mb image is not formed if some change is made in the asm code ...

My fault, but after trying the code after merging today, I noticed this.

[isoux]

Hello!
I have made little progress on this topic.

[IanSeyler]

Amazing work! So it loaded the full floppy disk into memory?

[isoux]

Yes, the entire disk in memory ...
We'll have a lot of work to do to agree on where it will be in memory.

[IanSeyler]

I can reserve 2MiB of the system memory to be used for the disk image. The next question is how the file system will be on the floppy. BMFS won’t work on a floppy.

[isoux]

... I'm planning to make a simple file system for floppy disks...

As I said in the first post, I am putting together a simplified FS for a floppy disk that I would use for my hobby os and of course to be implemented in this system of yours...

Since I use DMA to load the entire disk into memory, I need one temporary buffer of (3 tracks * 2 head) 3*0x4800 = 0xd800 or 55296 bytes, As you will see in the code, because DMA has 64K limits so its buffer cannot exceed them...
So for now dma_buff starts at 2Mb and mem_buff starts at 3 to 4,5 or 0x468000 Mb.

[isoux]

Hello Ian!
I invited you to the private repository BMFLFS (BareMetal FLoppy File System).
Let's agree on some things before I make the repo public.

[IanSeyler]

Sounds good. I was thinking about using something like a linked list to store files in a binary chunk. I may want to implement something similar for UEFI booting without a NVMe/AHCI drive

[isoux]

Please look there is it ok for me to use your license?
If it turns out positive, I would transfer the whole repo to you and I would just use the files for my hobby os?

[IanSeyler]

Please email me. It should be visible in my GitHub profile. We should work out how the files will be stored on the floppy disk. Ideally I would like to do the same for UEFI booting. That way the adjustments needed for BareMetal-Monitor will work on both.