Example of a High-Performance Directory Control Directory

Suppose you work as a securities analyst in a brokerage firm. Your department analyzes businesses and creates a CMS file for each firm on which you have an opinion. Every day or two, your department completes a few new opinions. All the stockbrokers in your firm read the reports and advise their clients of your opinions. They typically read the files while discussing investment options on the telephone with clients, so they need good access performance.

These opinion files are good candidates for placement in a high-performance DIRCONTROL directory. Because opinions are generated every day or two, the directory would not have frequent write activity. Furthermore, you could schedule the updates to occur near the end of the business day when there is little read activity. Your department members might, for example, create CMS files in their own subdirectories while they are forming an opinion. When their analysis is complete, they would wait until the end of the business day and copy the file to the DIRCONTROL directory.

During the day, your company's numerous stockbrokers would keep the directory accessed in read-only mode. They would benefit from having the opinions in a high-speed directory because it would reduce delays when they are retrieving an opinion for a busy client.

While the example being used is for a brokerage firm, the same requirements for high-speed directories are satisfied by many situations: electronic bulletin boards, forum directories, document libraries, and so on. To illustrate how you would set up a high speed directory, we will continue with the brokerage example.

First, you need to create a DIRCONTROL directory. To do so, specify the DIRCONTROL option on a CREATE DIRECTORY command: 
create directory vmsysu:yourid.opinions (dircontrol

If the directory already exists, you can convert it to a DIRCONTROL directory by doing the following:

  1. Ensure that all explicit locks for the directory and its files are deleted.
  2. Then enter: dirattr vmsysu:yourid.opinions dircontrol (force

    The FORCE option revokes all individual authorizations you've granted for the directory and the files within it. Remember that individual authorizations are not allowed in DIRCONTROL directories. The FORCE option also erases all aliases from the directory. (Aliases cannot exist in a DIRCONTROL directory.)

You can verify that the directory is directory control by entering: 
query dirattr vmsysu:yourid.opinions
If it is a DIRCONTROL directory, you will see: 
DIRCONTROL
Otherwise you will see: 
FILECONTROL
Next, you would grant DIRWRITE authority to your department. Assuming you have created a nickname, SA, for the securities analysis department, you would enter: 
grant authority vmsysu:yourid.opinions to sa (dirwrite

DIRWRITE authority allows your department members to create new files or update existing files in the directory. It also allows them to write to any file that is added to the directory in the future.

Next, grant DIRREAD authority to all the stockbrokers and anyone else who can use your computer system: 
grant authority vmsysu:yourid.opinions to public

DIRREAD is the default for GRANT AUTHORITY, when a DIRCONTROL directory is specified.

Finally, call the file pool administrator and ask to have your directory made data space eligible. The administrator will enter a DATASPACE ASSIGN command for your directory, and your stockbrokers will enjoy high-speed opinions.