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The File System describes where and how on the media the files and folders are located.
On optical media (CD, DVD, BD) a File System is often confused with a TOC but it is not.
The TOC describes the session and track layout of a CD or DVD it does not describe the files and folders. To understand the TOC better, read the section about the CD/DVD Layout.
There can be more than one file system per Session or Partition. In most cases the different File Systems point to the same files and the reason for the different File Systems exists to support as many different Operating Systems as possible. In some cases however, File Systems DO differ and one File System may for instance contain a driver to be able to read the other File System.
IsoBuster scans for all File Systems it supports and will show them all ! This allows for the user to select the File System he/she requires. It also provides alternative ways in case one File-System is corrupt but the other one isn't ! It's is a very powerful feature of IsoBuster in it's quest to be able to recover 'all' data !
You will recognize a File System as the icon connected to a Track or Partition icon in the left view.
IsoBuster fully supports :
The most common File System on all CDs and DVDs is the ISO9660 File System. It is however also the oldest and has some major disadvantages such as short file names (8.3) and a directory structure which can only be 8 levels deep. Because of these limitations it is almost always accompanied by one or more File Systems that don't have these limitations. However you need it if you want to see the content of the CD in an old DOS mode or an older Mac or Sun system.
Some mastering application sin against these limitations and allow to master ISO9660 with long file names and more directories deep. This shouldn't be a problem as of Windows 95 OSR2 but these CDs might cause problems in other systems. Of course IsoBuster has no problems with these CDs as well.
Sometimes this File System mentions for what system the CD was mastered. IsoBuster shows this with following Icons :
ISO9660 is recorded in a number of duplicate structures (with different byte order)
You should also read the section Options \ File System settings as you are able to influence how ISO is interpreted based on these duplicate structures.
Joliet is in fact an extension of ISO9660 and in many ways exactly the same. Some File System Volume Descriptors are different which allows OS to recognize this File System and prefer it if available. Joliet allows long file names and a directory structure which is substantially deeper.
It will be used automatically (preferred above ISO9660) by Windows 95 or higher.
Rock Ridge is also an extension of ISO9660 but never really became the standard (Joliet did). It was very popular on Commodore CDs and also was a way to allow for longer file names and more directories deep.
It is not supported by Windows and Windows will use the ISO9660 File System on such CDs
This File System starts with its own Volume Descriptor which has all the characteristics of Joliet but points to all the tables of the ISO9660 File System.
It is probably supported by Windows as I have only seen it on official Windows installation CDs. It is always accompanied by Joliet as well and Joliet is preferred above this File-System.
Another File System derived from ISO9660 standard but with some specific differences which prevent an ISO9660 interpreting system to always correctly deal with this File-System. It only appears on CD-i discs and these discs (besides this unique File System) also have some other 'features' which cause real problems on normal systems.
CD-i is not supported by Windows 95 or higher.
This is not really a File System, more an extra feature of the ISO9660 File System. CDs and DVDs can be made bootable but then the ISO9660 File System needs to be present alongside with the El Torito Volume Descriptor and a Virtual Floppy image. By just copying a Virtual Floppy image to a CD/DVD one does not make the CD/DVD bootable ! The File System needs to be setup as well. More about this here.
Bootable CDs and DVDs (or the El Torito standard if you will) needs to be supported by the BIOS of your PC system, not the Operating System. Older BIOS do not handle Bootable CDs well let alone bootable DVDs.
UDF is a universal file system that is being used more and more. It is used on CD, DVD, BD and you can format Hard Drives and USB sticks with it as well. There also have already been some major changes, so can you encounter UDF 1.02, UDF 1.5, UDF 2.01, UDF 2.5 and UDF 2.6.
- DVD and BD discs should always contain a UDF File-System.
- Packet Written Discs (CD-R and CD-RW), e.g. by Roxio Direct CD or Nero InCD use UDF 1.5
UDF 1.5 contains mechanisms to be able to append files and to be able to deal with defects on host side.
- Mount Rainier discs should contain UDF 1.02 again because the drive takes care of defect management.
- Hard Drives and USB sticks / Media cards can be formatted with UDF
UDF 1.02 is supported by Windows 98 or higher if the optical media is closed and contains a TOC. It is preferred over Joliet and ISO9660 if found.
What's the difference between : , and :
: This is the UDF file system which was found via the normal way, the way it is intended to find and explore a UDF file system, possible the same file system as found by other applications.
: This is a recovered UDF file system. It is assembled by putting all lost but found files and directories together. Where possible the tree structure is respected, but the files and directories in the root can come from everywhere. You can find this FS by using the function "Find missing files and folders".
: This is an old file system. This once would have been a green (normal icon) but afterwards files were added, altered or removed or the application just decided to write a new file system. A sequentially written media can contain lots of these and it allows you to go back in time looking at older documents and so on. You can find these by using the function "Find missing files and folders".
HFS is the Apple Mac file-system. It is used on all types storage media from Hard Drive and Flash media to CD and DVD. HFS itself is quite old and limited with regards to supported storage space, character-sets etc. Windows systems don't support HFS at all.
HFS+ is the modern variant of HFS with support for large storage space, unicode and much much more.
This is not a true file-system, it is a collection of IFO and BUP files inside an existing file-system, but this collection of files is used as a file-system by many (not all) standalone DVD Video / Audio players. This pseudo file-system relies on ISO9660 and more importantly on UDF to find the entry points.
This is not a real file-system but a flat file-list based on file-signatures, hence the name "SIG" or "EXT" from file-extension. This list is created during a scan for missing files and folders. More on this here.
FAT is a Microsoft invented file-system that has been around for a long time and it was first used on floppies in the days of DOS. FAT can be used on random writable media that has internal defect management, this includes DVD-RAM and BD-RE. FAT comes in three flavours, FAT 12, FAT 16 and FAT 32, all three formats are supported by IsoBuster. The number (12, 16 or 32) represents the amount of bits that are used to store a cluster address in. FAT32 is the most commonly used FAT file-system today because media these days is large, hence can contain a lot of sectors and clusters. Because FAT is used a lot on Hard Drives, Pen Drives / Memory sticks, Jazz and Zip drives, floppies etc., IsoBuster can also open a lot of image files created from such media.
NTFS is a Microsoft proprietary and preferred file system that can be found on Hard Drives and USB sticks. It is not possible to format optical media with NTFS. It is a closed book file-system and there are no specifications available for it. Support for NTFS has been implemented entirely through reverse engineering.
You may also want to read the section about : Write Applications and File Systems