Post subject: Writing *.bin Files To Floppy in Windows

Hello,
I'm trying to write my OS to an floppy disk, but when i try to boot up, Bochs says that i don't have any OS on that floppy, here is the command that i'm using to write:
#1 Try:

#2 Try:

Here is my code:

What is Wrong?
Thanks,
Nathan Paulino Campos

Post subject: Re: Writing *.bin Files To Floppy in Windows

Hi,

I'm not sure how other people do it, but if I were using Windows I'd create a floppy disk image using the assembler, and then use something like RawWrite to transfer it to a floppy disk (and/or use it directly in Bochs).
For an example (for NASM):

Of course when your project becomes more complex you may need to write your own utilities to create disk images (and other things).
Cheers,
Brendan

Post subject: Re: Writing *.bin Files To Floppy in Windows

Hi,
While there's probably nothing wrong with Rawrite, I'm just giving you an alternative: I like PartCopy which works very nicely. I have heard about people using MS Debug to do the same thing, but for some reason not many people seem to. I don't know whether that is because there's a problem with it or OS devvers just tend to prefer other utils...
That bit over, let's look at your command line (disclaimer: I guess Debug could overwrite you MBR if not used properly and I am not familiar with it myself, so please double check my command line below before you run anything).
Looking at your command lines below, and firing up help in the Debug program, it says that the format is:

Thinking about what you want to achieve, should your command line be more like:

You seem to supply address=100. I assume this is an offset in to your source file, and you want to copy from byte 0, this should be zero. Next is the drive letter (or number). You provide '0', which I would assume to be the primary hard disk (remember that I am not familiar with Debug, so you may be right on this one). Next, I assume are the sector and length you wish to copy to. I think your parameters here are correct (first sector = 0 (LBA), copy one sector).
Anyway, if the above does not work out, take a look at Rawrite / Partcopy. If you go down the Partcopy route, I think there's a bootsector-copying tutorial on www.osdever.net.
Cheers,
Adam

Post subject: Re: Writing *.bin Files To Floppy in Windows

Hi Nathan,
I have now had a chance to read through some of your other posts. Please do not take this as an insult, but I think you could do with some further background reading to help you understand what is going on.
Take a look at this link. It points to a specific page on Bona Fide OS Dev containing sample code and tutorials for boot sectors and gives some additional background information on the subject of booting. This is where I started out with assembly language and have now become more and more confident (I'd only used HLL's and dabbled with HLA before I found Bona Fide).
When you have the 'Hello World' tutorial up and running on the emulator of your choice (and have it on a real or virtual floppy disk), you have a 512b play area to experiment with. At this point, don't worry about breaking anything (you're on an emulator ). Just have a go with some BIOS int's, have a go at writing your own version of PutString, MemCpy etc... and verify with the emulator that they all work. At this point, have a go at loading your next stage from disk using int 0x13. If something goes wrong, read other tutorials and sample code and have a go at debugging. If you really get stuck, describe the symptoms, copy the Bochs register dump, describe what you have tried along with the exact error details and post it here.
Looking at debugging your sample above, there are really only a few reasons your Bochs will say that it cannot boot the floppy:
1. The boot signature is in the wrong place or is not present (a source file issue).
2. The floppy disk or disk image is not present (a toolchain issue).
3. There is no boot sector on the disk (a toolchain issue).
1 and 2 are very easy to fix. If you are not sure about #1, get yourself a hex editor and check that bytes 510 and 511 of your boot sector are as expected.
You are now left with #3. You can diagnose this issue fairly simply. You know that the bootsector is 512 bytes starting at offset 0. Does the floppy spin up when you attempt the write operation? If so, chances are you are not writing to the correct sector on the disk. Again, a hex editor can help you here (especially if you are using disk images instead of physical disks - see Virtual Floppy Drive). If the boot sector is in the wrong place on the disk surface, verify your command line.
I hope some of this helps - sorry for the size of the post(s)!
Cheers,
Adam

Post subject: Re: Writing *.bin Files To Floppy in Windows

Thanks now i write the floppy and my OS is booting!
Thanks very much!