8.3 naming, also known as short filenames (SFN), is a legacy file naming convention from early operating systems (like MS-DOS) that limits filenames to 8 characters for the base name and 3 characters for the extension (e.g., DOCUMENT.TXT). Modern Windows systems still support it for backward compatibility with older programs, generating an 8.3 equivalent for long filenames (e.g., DOCUME~1.TXT). This naming scheme was crucial for saving space on resource-constrained systems but is less relevant now, though it can sometimes cause issues or security reports in modern environments. 

Key Characteristics:

• Base Name: Maximum 8 characters (letters, numbers, and some symbols).
• Extension: Maximum 3 characters (after a single period).
• Single Period: Only one period allowed in the name. 

Why It Existed:

• Memory & Storage Limits: Early operating systems had severe restrictions on memory and storage, so short filenames were essential.
• CP/M Origin: The convention originated from the CP/M operating system and was adopted by DOS. 

Modern Relevance:

• Legacy Compatibility: Modern Windows (NTFS) creates 8.3 names for compatibility with older applications that don't understand long filenames.
• Vulnerability Reports: Some security reports flag the creation of 8.3 names as potential vulnerabilities, as they can sometimes expose more characters than intended.
• Disabling 8.3: It's possible to disable 8.3 name creation in Windows for specific needs, often via the Registry Editor. 

Example:

• A long filename like MyImportantDocument.docx might have a corresponding 8.3 name like MYIMPO~1.DOC. 

The term "8.3 naming" (or 8.3 filename format) refers to a file naming convention used in early computer operating systems like CP/M and MS-DOS, as well as older versions of Windows, which imposed a strict limit on the length of file names. 

Key Characteristics of the 8.3 Naming Convention

• Filename Length: The main part of the filename (the base name) was limited to a maximum of eight characters.
• Extension Length: This was optionally followed by a period (.) and a file extension of up to three characters.
• Supported Characters: Filenames could generally only contain uppercase letters, numbers, and a limited set of special characters like the underscore and hyphen. Spaces were not allowed.
• Operating Systems: This format was standard for the FAT (File Allocation Table) file system and was necessary due to the memory and storage constraints of early computing. 

Modern Relevance

Modern operating systems, including all current versions of Windows, primarily use long filenames (LFNs), which are much more flexible. However, they still support the 8.3 format for backward compatibility with legacy programs that might require it. 

For example, a file named MyGreatDocument.docx might have an automatically generated 8.3 format alternate name like MYGREA~1.DOC. 

System administrators can use the fsutil 8dot3name query command in Windows to check or modify whether this naming convention is enabled or disabled on specific volumes.