Creating direct access files

The z/OS NFS supports sequential access to direct access (DA) files. When creating a DA file, specify the dsorg(da) attribute (if it is not the default already) with the mount command or a file creation command (such as the vi UNIX command).

The direct access data set can only allocate on a single volume with the maximum size of 65535 tracks unless defined with a characteristic allowing increased sizes, such a Large Format. See z/OS DFSMS Using Data Sets for additional information on MVS file size limits.

To create a DA file, perform the following steps:

Create a local directory on your client to be used as a mount point. For example (with UNIX), enter this command:
```
$ mkdir /u/smith/mnt
```
Mount the MVS file system. For example, suppose your host is mvshost1, and you want to issue a mount on the high-level qualifier smith. You can enter this command:
```
# mount mvshost1:"/mvs/smith,dsorg(da)" /u/smith/mnt
```
If you do not specify any other attributes, the multiple virtual system (MVS) site defaults are used. You can use the showattr command to display the site defaults.
Next, you can use the vi UNIX command to actually create the new file.
```
$ vi /u/smith/mnt/new
```
You have just created a new MVS DA file named SMITH.NEW.

You can get the same results by specifying dsorg(da) in the file creation command, rather than in the mount command.

# mount mvshost1:smith /u/smith/mnt
$ vi "/u/smith/mnt/new,dsorg(da)"