In MS-DOS 6.0 and before (Windows 3.x and before) a maximum of 12 characters are allowed This is the so-called 8.3 format (8 characters, period, 3 characters, all upper case),
Under the early FAT file system, a filename consists of a base name of 1 to 8 characters plus an optional extension composed of a period plus 1 to 3 more characters. FAT filenames with an 8-character name and a 3-character extension are sometimes referred to as short filenames (SFNs) to distinguish them from long filenames (LFNs).
The LFN and NTFS file systems allow file names with a maximum of 255 characters. By default disks on modern PCs running Windows 95 or above are formatted with LFN support.
Mac OS X - up to 255 characters for files or folders, 27 characters for a disk volume
Mac OS 7.6, Mac OS 8.x, Mac OS 9.x - up to 31 characters for files and folders, 27 characters for a disk volume.
Macintosh System version 1 to version 7.5.5 - up to 31 characters for files and folders, 27 characters for a disk volume.
Note: Mac OS Standard (HFS) disks are readable by all Macintoshes, but that Mac OS Extended (HFS+) disks are only readable by Macs running Mac OS 8.1 or above. Macintoshes running Mac OS 9.x and below must have special files in the Extensions folder such as "ISO 9660 File Access", "Foreign File Access" and "High Sierra File Access" to read Joliet CDs intended for PCs.
Names can be up to 255 characters for files or folders.
The Joliet standard for Windows-NT or Windows-95 CDs limits your filename length to 64 unicode characters, but according to the UNIX mkhybrid man page (for Macintosh compatibility): "With all ISO9660 levels all filenames are restricted to upper case letters, numbers and the underscore (_). The maximum filename length is restricted to 31 characters, the directory nesting level is restricted to 8 and the maximum path length is limited to 255 characters." What limit will apply to any given system will depend on the level of support present on whatever software reads/writes the CD. Some software lets you set the length of the names with an option setting. MyCDPro, for example may let you choose between 12 characters, 106 characters, 128 characters and 212 characters. There is an interesting article here about SonyCDExtreme which says that software using the Prassi engine will support filenames up to 212 characters in length. Unfortunately this format is said to only work on XP/Win2K operating systems at this time. For RecordNow you need to go into the "options" menu, then "data", "advanced", and under "file system", choose: " iso level 2 (212 character file names)". Roxio V7 hides theirs by not putting a checkmark in 'Validate source files before recording'.
Another approach is to store file in .zip files or mountable images and burn or backup the resulting file. Imaging tools such as CDmage (freeware), Undisker and UltraISO (both shareware) can be used. UltraISO Joliet 5.5 and above will support filenames of 110 characters. UltraISO Joliet 6.51 supports super long filenames up to 221 characters. UltraISO Joliet 6.56 supports up to 255 characters in file names when a UDF volume is used. See UltraISO History
In MS-DOS 6.0 (which shipped with Windows 3.x) you can use alphabetic and numeric characters plus the punctuation marks ! # $ % & ( ) - ^ _ { } and ~ in both the base name and the extension of a FAT filename. Do not try to use the SPACE character. When Windows 95 shipped a few new characters were added like ' and @.
The LFN and NTFS file systems allow file names allow spaces and most other characters that are not allowed in a FAT system file name, See your operating system documentation for details on the characters allowed. / \ : * ? " < > | are not allowed under Windows XP. You can get a list of the illegal characters by trying to type one while renaming a file.
Upper and lower case letters are both legal in LFN filenames, but you can not have two files in the same folder that are spelled the same like "SAM" and "Sam" and "sam".
Mac OS X - any character legal except colon ( : ), ( real bad idea to use /, illegal in MS Word)
Mac OS 7.6, Mac OS 8.x, Mac OS 9.x - any character legal except colon ( : ), ( real bad idea to use / )
Macintosh System version 1 to version 7.5.5 - any character legal except colon ( : ), ( real bad idea to use / )
Upper and lower case letters are both legal in Mac filenames, but you can not have two files in the same folder that are spelled the same like "SAM" and "Sam" and "sam". You may occasionally encounter filenames which are not displayed the way you expect if you have used characters from outside the U.S. English character set in the name. These are generally due to problems in the way your operating system translates characters between the OEM and ANSI character sets. Correcting the problem may require experimentation with fonts, character sets, and code pages, and occasionally some such problems may not be readily correctable within the command processor. Using accented letters or any other character type using the option key ( like a bullet ) is a very bad idea for filenames.)
Any character is legal in a filename except slash ( / )
Upper and lower case letters are both legal in filenames, and you CAN have two or more files in the same folder that are spelled the same like "SAM" and "Sam" and "sam".
For cross platform compatibility keep your filenames 31 characters or less if you are on UNIX or a PC and avoid putting / \ : * ? " < > | in a filename if you are on UNIX or a Macintosh. You can search for offending characters on a CD you are about to burn for PC users. It is also a good idea not to put more than one period in a filename and not to put one as the first or last character of the filename. Use of capitalization with religious consistency or putting html files onto a UNIX server will result in dead links. Putting a comma or semicolon in a filename could cause major problems under various circumstances on any platform when working with lists of filenames and should be avoided. A space or percent sign may be a little safer, but for the web a %20 will be automatically inserted in place of a space. If a user on one platform downloads part of a site hosted on another platform, links may break if spaces or % are used in names.
CD-R: CD-Recordable. These are WORM (Write Once, Read Many).
CD-RW: CD-Rewritable. These are WMRM (Write Many, Read Many).
CD-Rs are universal and should be readable in any CD-ROM drive.
CD-RWs should be readable in all contemporary drives. A drive must be "multiread" to be able to read CD-R and CD-RW disks. Older drives are troublesome. Retire that old 4x drive and buy a new one; it's not worth the irritation.
CD-UDF (Universal Disk Format): Industry-standard incremental packet-writing filesystem.
CD-Bridge: CD format that includes extra information on a CD-ROM/XA track, so that it can be played on a CD-I or CD-ROM/XA drive
CD-DA: Compact Disc - Digital Audio
CD-Extra: a multisession CD featuring audio and data
CD-I: Compact Disc - interactive. A multimedia CD format
Yellow Book Specifications: Physical format for data CDs
Orange Book Specifications: Physical format for recordable CDs:
Blue Book Specifications: Format for CD Extra
Green Book Specifications: Format for CD-I
Red Book Specifications: Format for CD-Rs playable in audio CD players
White Book Specifications: Format for Video CD
El Torito: Bootable CD-ROM format specification
FAT: File Allocation Table. The component of an MS-DOS or Windows 95 file system which describes the files, directories, and free space on a hard disk or floppy disk.
HFS (Hierarchical File System): Native file system used by Macintosh
High Sierra Format: A specification for the file structure of CD-ROMs. The name is derived from that of an ad hoc group of CD-ROM researchers and developers which named itself the High Sierra Group following a meeting at the High Sierra Hotel at Lake Tahoe, California. Later a modified version of the High Sierra format was accepted by the [International Organization for Standardization] as the international standard ISO 9660 in 1988.
Hybrid CD: CD-ROM standard readable by PCs and MACs
ISO-9660: The old file layout standard, allowing only 8.3 filenames
Joliet: Microsoft extension to the ISO 9660 filesystem that allows Unicode characters to be used in filenames, as well as long filenames. It also creates truncated filenames for MS-DOS compatibility (these weird-looking things: FILENA~1.TXT). It allows filenames up to 64 characters, including spaces, and is readable by Windows 95 or later, and Macintosh computers running the Joliet Volume Access extension. Macs will not read Joliet file names longer than 31 characters.
Mixed Mode: a format including a data track and one or more audio tracks
Multisession: Allows adding files over time, rather than during a single session. For a disk to be readable, the session must be "closed." However, this prevents adding more files to the disk. Multisession links the individual sessions and update the disk's table of contents so that it appears as a single directory.
NTFS: The native file system of Windows NT.
Rock Ridge: Extensions to ISO-9660 allowing long filenames and UNIX-style symlinks; preserves all file attributes, such as ownership and permissions. UNIX file attributes are not displayed when the disk is read on a Windows system.
Disk-At-Once (DAO): a whole CD is written to without turning the laser off, i.e. there is only one track burned.
Track-At-Once (TAO): when the CD is written the laser is turned on and off between tracks, leaving a small gap between audio tracks
Filenames Used By DOS & WIN 95
Mac & Windows OS File/Folder naming rules