Using DOS Files on DOS Disks

You can have DOS disks attached to your virtual machine by a directory entry or you can link to a DOS disk with the LINK command. You can use the ACCESS command to assign a mode letter to the disk:
access 155 b
and the RELEASE command to release it:
release b

Except for VSAM disks, you cannot write on DOS disks or update DOS files on them. You can, however, execute programs and CMS/DOS commands that read from these files, and you can use the LISTDS command to display the file IDs of files on a DOS disk.

For example, if you enter:
listds b
You receive the following response, if the data set exists:
FM DATA SET NAME
B  NEW.TEST DATA
B  ONE.TEST ONE
B  TWO.TEST TWO
You can also verify the existence of a particular file. For example, if the file-id is NEW.TEST.DATA you can enter:
listds new.test.data.b
      — or —
listds new test data b
If the file-id of the DOS file you want to verify contains embedded blanks, for example NEW.TEST DATA, then you have to enter the LISTDS commands with a question mark:
listds ? b
CMS responds:
Enter data set name:
and you can enter the exact file-id:
new.test data
If the data set exists, you receive a response:
FM DATA SET NAME
B  NEW.TEST DATA