Re: Strange 2.4.2 boot error
Hi folks and D. Stimits, Summary of discussion taken place so far (for linux-kernel people): D. Stimits noticed he can not boot his kernel from a 1.44MB floppy created with "make bzdisk". This would lead into a register dump. The dump does show the boot code tries to read track 80 of the disk. However mkbootdisk as delivered with a pre-release of the RedHat 7.1 distribution can be used to create a working boot disk using the bzImage generated by above. My last question to D. Stimits was: > > How large is the file ./arch/i386/boot/bzImage? And he answered > 1040155 Feb 24 23:28 bzImage > > Definitely within 1.44 Mb floppy size. I see following problem with the bootsector code for bzImage: Within bootsector the size of the kernel is stored as number of 16 byte blocks. This gives a number of 0xfdf2 in this case. Now while loading the kernel the bootsector code calls a helper routine (in setup[.S]) which does copy 64kByte if available and does nothing else. This routine does the return the number of 16 byte blocks read. This number then is a multiple of 1000h. So no when a kernel of above size is completely loaded the count of the 16 byte blocks returned by the helper routine wents from f000h into h due to the 16 bit size of the register ax used. The bootsector code does then compare h to fdf2h and it is less, so it does continue loading until it does reach the end of the disk and fails with a read error. Malware - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: Strange 2.4.2 boot error
Hi folks and D. Stimits, Summary of discussion taken place so far (for linux-kernel people): D. Stimits noticed he can not boot his kernel from a 1.44MB floppy created with "make bzdisk". This would lead into a register dump. The dump does show the boot code tries to read track 80 of the disk. However mkbootdisk as delivered with a pre-release of the RedHat 7.1 distribution can be used to create a working boot disk using the bzImage generated by above. My last question to D. Stimits was: How large is the file ./arch/i386/boot/bzImage? And he answered 1040155 Feb 24 23:28 bzImage Definitely within 1.44 Mb floppy size. I see following problem with the bootsector code for bzImage: Within bootsector the size of the kernel is stored as number of 16 byte blocks. This gives a number of 0xfdf2 in this case. Now while loading the kernel the bootsector code calls a helper routine (in setup[.S]) which does copy 64kByte if available and does nothing else. This routine does the return the number of 16 byte blocks read. This number then is a multiple of 1000h. So no when a kernel of above size is completely loaded the count of the 16 byte blocks returned by the helper routine wents from f000h into h due to the 16 bit size of the register ax used. The bootsector code does then compare h to fdf2h and it is less, so it does continue loading until it does reach the end of the disk and fails with a read error. Malware - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
