Can't get floppy driver to work.

ad2017 · **Joined:** Sun Nov 24, 2019 6:32 am **Posts:** 1

Hello! I am kinda new to OS development. I have tried following this tutorial to make a floppy driver, but when I try reading the first sector, I always get the same data back, even when no floppy is attached, or when the floppy is empty (and the data I get back is not empty). I tried looking back at the tutorial, but I can't find the problem. Any help?

Attachment:

floppy.c [5.84 KiB]
Downloaded 19 times

(also I'm sorry for the ugly code)

Octocontrabass · **Joined:** Mon Mar 25, 2013 7:01 pm **Posts:** 5143

Code:

#define FLPY_SECTORS_PER_TRACK 80

A typical 1.44MB disk is formatted with 18 sectors per track. You can't fit 80 sectors in a single track.

Looks like we don't have this particular mistake documented yet.

neon · **Joined:** Sun Feb 18, 2007 7:28 pm **Posts:** 1564

Hi,

So, we looked into this one and have noticed that FLPY_SECTORS_PER_TRACK is defined incorrectly in the text but is correct in the demo download as noted below. The text has been corrected. The demo defines it as the following:

Code:

const int FLPY_SECTORS_PER_TRACK = 18;

Octocontrabass · **Joined:** Mon Mar 25, 2013 7:01 pm **Posts:** 5143

The downloadable code is correct, but the text in the tutorial is wrong.

Quote:

FLPY_SECTORS_PER_TRACK is 80. Great!

Not great! :lol:

Edit: and I see it's been corrected as I was writing this post. Very nice!

There are some other mistakes, such as "linear block address" (LBA is short for logical block address), and calling the floppy drive connector cable a form of PATA/IDE cable (neither ATA nor IDE existed when that cable was standardized), but those details aren't too important for writing a driver.

OSDev.org

Can't get floppy driver to work.

Who is online