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FreeDOS kernel - implements the core MS-DOS/PC-DOS (R) compatible operating system. It is derived from Pat Villani's DOS-C kernel and released under the GPL v2 or later. Please see http://www.freedos.org/ for more details about the FreeDOS (TM) Project.
http://kernel.fdos.org/
GNU General Public License v2.0
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initdisk: actually restrict disk size to 2TB instead of modulo 2TB, fix ExtLBAForce usage #118

Closed boeckmann closed 11 months ago

boeckmann commented 11 months ago

Hey Jeremy,

I had a look at the recent changes and found some places where I am not sure that it is correct. For instance, I think ExtLBAForce originally was meant to force LBA access for partitions contained inside an extended partition of type LBA (0x0E).

ExtLBAForce is now set in LBA_Get_Drive_Parameters to InitKernelConfig.ForceLBA. I understand you somewhat wanted to force the use of LBA (it is not clear to me in what case exactly), but setting ExtLBAForce in LBA_Get_Drive_Parameters is in my opinion a) the wrong variable and b) the wrong place for it.

I relocated the ExtLBAForce setting to ProcessDisk, setting it initially to zero. I think this is the right layer of abstraction for it. LBA_Get_Drive_Parameters should only do what it is named after: getting drive parameters. Otherwise it is getting even more confusing.

In this merge request I also restrict the disk size to 2TB. It was modulo 2TB before, leading to a 3TB disk becoming a 1TB disk.

It also includes other minor changes (should be reviewed).

Greetings, Bernd

PerditionC commented 11 months ago

I will revisit the forcelba logic. from my phone the changes looked good, but I will look better tonight. I had to force LBA access for testing as my VirtualBox BIOS was failing the check and reverting to CHS for my 2TB fake drive although it works fine to access using LBA. I have a different branch where I am reworking initdisk with GPT support, I just didn't want to bring over too many changes as I want to get 2044 release out then work on a 2045 with GPT support shortly after. Thanks for reviewing the changes!

boeckmann commented 11 months ago

I had to force LBA access for testing as my VirtualBox BIOS was failing the check and reverting to CHS for my 2TB fake drive although it works fine to access using LBA.

Well, that is interesting! Now I see what you wanted to achieve, basically forcing LBA even if the BIOS says it does not support it. Do you know where exactly this check failed, the INT13,41 or INT 13,48 call?