They have the following structure: ← 2,048 bytes → Parts Type Identifier (always 'CD001') Version (always 0x01) Data Sizes 1 byte 5 bytes 1 byte 2,041 bytes The data field of a volume descriptor may be subdivided into several fields, with the exact content depending on the type.
Volume descriptor Each volume descriptor is 2048 bytes in size, fitting perfectly into a single Mode 1 or Mode 2 Form 1 sector. Collectively the volume descriptor set acts as a for the data area, describing its content (similar to the used by, and formatted disks). Volume descriptor set The data area begins with a set of one or more volume descriptors, terminated with a volume descriptor set terminator. As the structures have been designed with unaligned members, this 'both endian' encoding does however not help implementors as the data structures need to be read byte-wise to convert them to properly aligned data. All multi-byte values are stored twice, in and format, either one-after-another in what the specification calls 'both-byte orders', or in duplicated data structures such as the path table. For example, a CD-ROM may contain an alternative file system descriptor in this area, as it is often used by to offer -specific and -specific content.
In 2013, ISO published Amendment 1 to the ISO 9660 standard, introducing new data structures and relaxed file name rules intended to 'bring harmonization between ISO 9660 and widely used ' Specification'.' Specifications Overall structure The following is the rough overall structure of the ISO 9660 file system: ISO 9660 File System System Area (32,768 B) Unused by ISO 9660 Data Area Volume Descriptor Set Path tables, Directories and Files The System Area, the first 32,768 data bytes of the disk (16 sectors of 2,048 bytes each), is unused by ISO 9660 and therefore available for other uses.
0 kommentar(er)
