1    /LOGICAL_IO

    Specifies that the target GPT is to be accessed using Logical I/O
    operations.

    If neither /LOGICAL_IO nor /VIRTUAL_IO is specified, GPT access
    using Virtual I/O will be attempted first and followed by an
    attempt to use Logical I/O if [000000]GPT.SYS is not found.

    If the file [000000]GPT.SYS is correctly placed on the disk, the
    output of /LOGICAL_IO and /VIRTUAL_IO will be the same.

2    /VIRTUAL_IO

    Specifies that the target GPT is to be accessed using Virtual I/O
    operations.

    If neither /LOGICAL_IO nor /VIRTUAL_IO is specified, GPT access
    using Virtual I/O will be attempted first and followed by an
    attempt to use Logical I/O if [000000]GPT.SYS is not found.

    If the file [000000]GPT.SYS is correctly placed on the disk, the
    output of /LOGICAL_IO and /VIRTUAL_IO will be the same.