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 structure

Would you take every single piece of paper related to your business 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

Maintaining Order

Technical documentation

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