Add FileIO::write to ATA

[vinc]

Allow users to write sectors to hard drives directly via the device files in /dev/ata

[vinc]

For a long time I wanted to try to copy the bootloader from memory at 0x7C00 and the kernel at 0x400000 and see if I could get a working boot image with it, but a few bits differs. We can get them elsewhere, for example we can find 31 C0 at 0xB420 to replace the first two bytes of the first sector of the loader (that are 00 00 in memory), this make the OS boot pretty far but not without issues.

> memory dump 0xB420 2 > /ini/kernel.img          # 0x31C0
> memory dump 0x7C02 53246 >> /ini/kernel.img     # Loader
> memory dump 0x400000 2244608 >> /ini/kernel.img # Kernel
> read /ini/kernel.img > /dev/ata/0/1
> disk format /dev/ata/0/1

Now that large downloads are possible it's going to be easier to just download an image of the kernel from the network instead of trying to rebuild it from memory.

[vinc]

The kernel image is a bit too large to be downloaded directly so #773 will add zlib support to download a compressed version.

[vinc]

Now we can do this to install the loader and the kernel image at the beginning of the disk:

> pkg install kernel
> read /ini/kernel.img > /dev/ata/0/0

[vinc]

We could add a zero program or script that would continuously output 0 to stdin until interrupted to replace disk erase /dev/ata/0/0 with zero => /dev/ata/0/0.

We could also do print /dev/random => /dev/ata/0/0 but each buffer written to stdin should be a multiple of 512 bytes in length.