cstarter wrote:

> 
> Now ,I have known what you said .But when we assemly the code , and 
> write the binary file to the floppy ,The 1st sector will be overwritten.
> Then BPB is destroyed .
> Thanks for you reply .

If you directly write it yes, but it is not meant to be used that way.
You need to read the existing BPB first, then copy the relevant portion
into the new boot sector, and lastly write the modified version to disk,
thus preserving the needed information.  This is part of what sys does
when installing the boot sector.

If you know the geometry, such as you are putting it on a 1.44MB floppy,
you can have the default boot sector contain a proper BPB (such as I
believe oemboot.asm or the modified for EnhandedDR-DOS boot sector), but
without the above steps to retrieve the existing BPB information, it
will only work for that specific disk geometry.

Jeremy





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