When you install SQL Server the setup program creates the MASTER database device, which is used to store the master, model, and tempdb system databases and transaction logs and, optionally, the pubs sample database and transaction log. During installation, the setup program prompts you to provide settings for these MASTER database device options:
The directory and filenames must conform to the FAT 8.3 naming convention, even if installed on an NTFS volume.
Note that if you later determine you need additional device space, you can use DISK RESIZE to increase the size of the MASTER database device. For information about DISK RESIZE, see the Microsoft SQL Server Transact-SQL Reference.