HP 3000 Manuals

Understanding Your System

Maintaining Order 

Your MPE/iX computer maintains order on the system through two closely
related forms of organization.

logging on          Logging on is your way of fitting yourself into the computer's
                    organization.  By logging on with the HELLO command, you answer the
                    computer's most important questions.

                       *   Who are you?

                       *   Where do you want to fit into my organization?

                       *   Do you have the authority to do this?

                    Logging on identifies you to the computer.  Just as important, it
                    tells the computer whether you have the authority to do certain
                    kinds of work on the computer.

the account         Would you take every single piece of paper related to your business
structure           and throw them all into one box?  You might, if you have a very 
                    small business.  More likely, you want to organize all your papers
                    into some structure that allows you to find things easily.

                    For many businesses, the filing cabinet with drawers and folders
                    provides a place to put papers.  More important, it provides a way
                    to keep together those pieces of paper that belong together and to
                    keep separate those pieces of paper that are unrelated to each
                    other.

                    The computer's account structure provides the same solution for
                    those who use the computer.

   *   An account is like a filing cabinet.

       Unlike the filing cabinet in your office, an account may be as
       large, or as small, as you need.  You may have almost as many
       accounts on your computer as you like.  Accounts do take up room
       on the computer:  in its memory and on its disks.  But if you are
       willing to buy more and more disks, you can create accounts almost
       to your heart's content.

   *   Users are somewhat like the keys to a filing cabinet.

       You might create an account called XM661A. And you might specify
       that a user called M661 is entitled to access (open and use) the
       account that you created.  It might make more sense to call an
       account MYACCT. It would certainly be easier to remember.  And it
       might make more sense to call a user JOHN. That, too, is easier to
       remember.  The choice is up to you--more accurately, the choice is
       up to the person who sets up and manages your computer system.

   *   A group is like one of the drawers in a filing cabinet.

       Unlike the drawer of your filing cabinet, a group may be as large,
       or as small, as you need.  And, within the limits of your
       computer's disk space and memory limits, you may have as many
       groups in an account as you need.

   *   Files are comparable to the pieces of paper (or folders) that you
       store in a drawer of the filing cabinet.  In the computer, files
       are kept in groups.  Again, within the limits of your computer's
       disk space and memory limits, you may have as many files in any
       group as you need.

   *   the hierarchical file system 

       The MPE/iX file system has been expanded so that it is
       hierarchical (tree structured) and can contain files at many
       different levels.  This organization provides a special kind of
       file called a directory.  Instead of holding data, directories
       contain lists of files and pointers to those files.  A directory
       can also contain other directories.  For more information on the
       hierarchical file system, refer to the book, New Features of 
       MPE/iX: Using the Hierarchical File System (32650-90351).


          Figure 2-1.  Files in Groups, Groups in Accounts 

Just as important, the account structure offers a method of protecting
sensitive files from tampering, and sensitive programs from abuse.

You may create passwords that anyone wishing to use the system must know
before he or she can log on.

   *   Accounts may have passwords.

   *   Groups may have passwords.

   *   Users may have passwords.


          Figure 2-2.  Files--In Groups, In Accounts 

In addition to the traditional group, file and account structure
mentioned previously, you can now use the hierarchical file system shown
below.  The hierarchical file system is tree structured and can contain
files at many different levels.  You can also create files and
directories under accounts.  For more information on the hierarchical 
file system, refer to the book, New Features of MPE/iX: Using the 
Hierarchical File System (32650-90351).


          Figure 2-3.  Hierarchical File System 

MPE/iX 5.0 Documentation