Ví dụ, hãy xem xét của IBM. Hướng dẫn hệ thống 360/370 MVC (di chuyển nhân vật), có thể di chuyển lên đến 256 byte từ một địa điểm để một vị trí khác (có thể chồng chéo). Nếu một trong hai khối (nguồn hoặc đích) nằm giữa một ranh giới trang, một trang lỗi có thể xảy ra sau khi di chuyển là một phần được thực hiện. | File-System Implementation 417 Boot information can be stored in a separate partition. Again it has its own format because at boot time the system does not have file-system device drivers loaded and therefore cannot interpret the file-system format. Rather boot information is usually a sequential series of blocks loaded as an image into memory. Execution of the image starts at a predefined location such as the first byte. This boot image can contain more than the instructions for how to boot a specific operating system. For instance PCs and other systems can be dual-booted. Multiple operating systems can be installed on such a system. How does the system know which one to boot A boot loader that understands multiple file systems and multiple operating systems can occupy the boot space. Once loaded it can boot one of the operating systems available on the disk. The disk can have multiple partitions each containing a different type of file system and a different operating system. The root partition which contains the operating-system kernel and sometimes other system files is mounted at boot time. Other volumes can be automatically mounted at boot or manually mounted later depending on the operating system. As part of a successful mount operation the operating system verifies that the device contains a valid file system. It does so by asking the device driver to read the device directory and verifying that the directory has the expected format. If the format is invalid the partition must have its consistency checked and possibly corrected either with or without user intervention. Finally the operating system notes in its in-memory mount table structure that a file system is mounted along with the type of the file system. The details of this function depend on the operating system. Microsoft Windows-based systems mount each volume in a separate name space denoted by a letter and a colon. To record that a file system is mounted at F for example the operating .
