Editing File system (section)

===Conversational Monitor System===
{{Main|CMS file system}}
The IBM [[Conversational Monitor System]] (CMS) component of [[VM/370]] uses a separate flat file system for each [[virtual disk]] (''minidisk''). File data and control information are scattered and intermixed. The anchor is a record called the ''Master File Directory'' (MFD), always located in the fourth block on the disk. Originally CMS used fixed-length 800-byte blocks, but later versions used larger size blocks up to 4K. Access to a data record requires two levels of [[indirection]], where the file's directory entry (called a ''File Status Table'' (FST) entry) points to blocks containing a list of addresses of the individual records.