Bios disk read error help

abstractmath · **Joined:** Mon Sep 07, 2020 5:50 pm **Posts:** 46

Actually, scratch my last post. It seems to be working now? I think I forgot to rebuild my project or something.

abstractmath · **Joined:** Mon Sep 07, 2020 5:50 pm **Posts:** 46

Oh that's funny. I still can't read past 40 blocks, even with the BIOS extension.

Octocontrabass · **Joined:** Mon Mar 25, 2013 7:01 pm **Posts:** 5137

Does your disk have 40 blocks?

abstractmath · **Joined:** Mon Sep 07, 2020 5:50 pm **Posts:** 46

I'm not entirely sure. How can I check?

Octocontrabass · **Joined:** Mon Mar 25, 2013 7:01 pm **Posts:** 5137

How big is one block?

How big is your disk?

How many blocks can fit in your disk?

abstractmath · **Joined:** Mon Sep 07, 2020 5:50 pm **Posts:** 46

I. Do. Not. Know. I'm looking at int 13h on wikipedia and I do not know how to get that information. Do I use AH = 0x48 or is there something better suited to what I need to know???

Octocontrabass · **Joined:** Mon Mar 25, 2013 7:01 pm **Posts:** 5137

If you're reading a hard disk with INT 0x13, the block size is 512 bytes. The specifications allow for different block sizes, but in practice no BIOS supports it.

abstractmath · **Joined:** Mon Sep 07, 2020 5:50 pm **Posts:** 46

Is there a way that I can specify a drive size in qemu? I think that might help a bit.

Octocontrabass · **Joined:** Mon Mar 25, 2013 7:01 pm **Posts:** 5137

Of course.

The drive size is determined by the size of the disk image you're using.

abstractmath · **Joined:** Mon Sep 07, 2020 5:50 pm **Posts:** 46

Ohhhhh okay, now it's making sense. My entire image file is about 21K in size, and that would make sense that the drive size wouldn't be past 40 blocks since 40 * 512 = ~21K.

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Bios disk read error help

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