The name of a file or directory can have two parts: a name and an optional extension. The two parts are separated by a period (for example, MYFILE.NEW). The file name used was invalid. When using MS-DOS, you will need to use the following conventions for naming files and directories:
The name of a file or directory can have two parts: a name and an optional extension. The two parts are separated by a period (for example, MYFILE.NEW).
The name can contain up to eight characters, and the extension can contain up to three characters.
The name must start with either a letter or number. It can contain any uppercase or lowercase characters (file names are not case-sensitive) except the following:
period (.) quotation mark (")
slash (/) backslash (\)
brackets ([ ]) colon (:)
semicolon (;) vertical bar (|)
equal sign (=) comma (,)
The name should not contain any spaces. The following names are reserved and cannot be used for files or directories: CON, AUX, COM1, COM2, COM3, COM4, LPT1, LPT2, LPT3, PRN, and NUL. Examples of valid file names are LETTER.DOC, MEMO.TXT, BUDGET.92, 12345678.901 and 2NDTRY.RPT.