Changes between Version 3 and Version 4 of Ticket #41, comment 13


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Timestamp:
Apr 25, 2017, 11:41:07 AM (8 years ago)
Author:
Valery V. Sedletski

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  • Ticket #41, comment 13

    v3 v4  
    1 But it is legal for FORMAT program to change partition type field in MBR. It is done by HPFS/JFS FORMAT too. So why not allow to write there? If I only change the partition type, nothing will happen. In the worst case, if MBR will be destroyed, the FS can be not mounted and nothing will happen. And, you can notice if the partition is zeroed-out and invalidate the MBR sector too. And why restrict big floppies to FAT/FAT32/exFAT? HPFS big floppies should work too. And BTW, in Linux, you can have even a hard disk without a partition table, and mount as a whole. Indeed, no difference between a flash disk and a hard disk. If not FAT-based FS, you can set partition type indicator to 0x7 (IFS), then any FS may be used on a big floppy. In fact, I suspect that you can set partition indicator to 0x7 for all FS's and it should work.
     1But it is legal for FORMAT program to change partition type field in MBR. It is done by HPFS/JFS FORMAT too. So why not allow to write there? If I only change the partition type, nothing will happen. In the worst case, if MBR will be destroyed, the FS will not mount and nothing will happen. And, you can notice if the partition is zeroed-out and invalidate the MBR sector too. And why restrict big floppies to FAT/FAT32/exFAT? HPFS big floppies should work too. And BTW, in Linux, you can have even a hard disk without a partition table, and mount as a whole. Indeed, no difference between a flash disk and a hard disk. If not FAT-based FS, you can set partition type indicator to 0x7 (IFS), then any FS may be used on a big floppy. In fact, I suspect that you can set partition indicator to 0x7 for all FS's and it should work.
    22
    33PS: in FORMAT, I see hidden sectors != 0 on USBMSD.ADD-emulated big floppy, so I decide that it is partitionable media, because the boot sector is not the 1st one. So, it is quite legal to access MBR and write there. And, I have no means to distinguish between emuulated and non-emulated media, so I cannot decide if I need to avoid writing to the MBR. So, it would be better to allow wirting there.