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Understanding Your System: HP 3000 Series 9X8LX Computer Systems > Chapter 2 Where Am I?
Logging On Computer?Starting a Session |
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Logging on with the HELLO command starts a computer session—a dialog between you and the computer—and permits you to give instructions at your terminal, one at a time, to the computer. The computer attempts to carry out each instruction as soon as it can. If you enter something that the computer does not understand, or that it cannot for some reason execute, the computer will inform you by displaying an error message on your video terminal. Receiving an error message does not mean that you were wrong. You may have intended to enter exactly what you entered. It does mean that the computer has found something about your entry that does not fit the rules that it must obey. This is a simple log on:
HELLO is the command to log on and start a session. Here the user JOHN is starting a session and opening the group called MYGROUP in the account called ANYACCT. Notice the order in which the log on is specified.
If passwords are required, the computer will ask (prompt you) for each of them, one at a time, and wait for your response. In that case, you would have to enter each password correctly in response to the computer's request. The passwords that you type will be invisible to you and to everyone else. The computer will read what you enter, but it will not display the passwords on your video terminal as you type them. This prevents others from looking over your shoulder to discover the passwords that you are using.
This is one way of logging on:
Logging on this way opens one "drawer" of a computer "filing cabinet."
Here is another way of logging on:
Logging on this way opens still another drawer—a rather special drawer—in the filing cabinet called ANYACCT. But that is a subject for "Logging on Without a Group". But where are the filing cabinets in the computer? Accounts (the filing cabinets), their groups, and the files within those groups are kept on the computer's disk or disks, which correspond to file rooms in an office. The log on does not by itself give you direct access to any particular file. Rather, it specifies a group in an account where the file is to be found. If a file called MYREPORT is found in the MYGROUP drawer of the ANYACCT filing cabinet, its full address (location) is this:
It happens--and not at all by accident--that the complete address (location) of a file in the account structure is exactly the same as its full name.
There might be many files in the same group of the same account. These three files are found in the same group and account in the account structure:
Each has the same group name and account name. But each has a unique, fully qualified file name. Each has a unique address or location in the computer. It must be so--two files cannot have the same fully qualified file name on the same disk. When would you use the fully qualified name (address) of a file? You would use it whenever you need access to that file but you are not logged on in the right group or account.
The day will come when you want to find a file and you cannot remember where it is. Unlike the filing cabinet in the corner of your office, the computer can tell you where to find a file, provided the file exists. If you remember the first name of the file, the computer can find it quickly. If you remember only a part of the name, the computer can still find it--or at least show you file names that are close to the one that you are searching for. The LISTFILE command does the searching. If you did not know where to find the TAXRPT program, you would use LISTFILE TAXRPT.@.@,6 to locate it. If TAXRPT is found on the system, the LISTFILE command will tell you which group and which account contain TAXRPT.
You might, however, have many file names that begin with the letters T A X R P T--TAXRPT91, TAXRPT92, TAXRPT93.... And, you might recall that all of them are in the ANYACCT account. If that were the case, you could enter this:
This tells the computer: "Look for any file name beginning with TAXRPT, in any group, in the ANYACCT account." Suppose, however, that the files were named this way: JNTAXRPT, FBTAXRPT, MRTAXRPT, MYTAXRPT.... In that case, enter this:
"Look for any file names that end in TAXRPT in any group in the ANYACCT account." You might, as an experiment, enter this command:
This will find--and display--the fully qualified names of all of the files on your system. The list could be quite long, and the display could take time. Pressing Break will break the command and its display and return the prompt to your screen.
With this release, LISTFILE contains additional ways to display information about files. For more information and examples, refer to the book Commands Reference - HP 3000 Series 9X8LX (B3813-90011). User names, such as JOHN, have no bearing on the location of a file, a group, or an account. They are, however, indispensable for logging on to an account. Equally important, when you combine a user name with an account name (JOHN.ANYACCT), you identify the creator and "owner" of a file. Whoever logs on using JOHN.ANYACCT and creates a file--in any group in the ANYACCT account--is identified as the creator and owner of that new file.
Someone logging on with ALICIA.ANYACCT might be unable to use the newly created file--unless the owner identified as JOHN.ANYACCT uses the RELEASE command to suspend the normal security on that file. Security is restored to that file only after JOHN.ANYACCT uses the SECURE command. Ownership information is attached to the computer's record of any file that JOHN.ANYACCT creates. ALICIA.ANYACCT might create files, too, and the computer would know that certain files "belong" to ALICIA.ANYACCT and that others "belong" to JOHN.ANYACCT. User names have still another purpose that is described in “Logging on without a group” and in “TIP” in Chapter 4. Still another kind of name might be found in a log on. In this example, the word BUDGET has been added:
BUDGET is a session name. A session name has no bearing on the location of a file, group, or account. It has no bearing on the user name JOHN, either. So what is its value? It is entirely possible to find that two or more people have logged on to the same group, in the same account, using the same user name (HELLO JOHN.ANYACCT,MYGROUPReturn). If more than one person has logged on to a group using the same user name, each might add a different session name to his or her log on to help minimize confusion. In most cases, your printer will add any session name to the banner page that precedes each print out (as well as the log on identity of the user doing the printing). Session names are a convenience for the people using the computer. The computer will not become confused if two different people log on using the same user name, the same account name, and the same group name, even if those people neglect to use a session name. Every time someone logs on to the computer, the computer starts a new session and assigns that session a unique session number (such as #S373). You will see session numbers if you use the SHOWJOB command. You may choose any session name that you like when you log on, provided the name begins with a letter is followed by no more than seven other letters or numbers, or a combination of letters and numbers.
Ownership is one form of protection for files. Using passwords is another form of protection. Passwords may be attached to the following parts of a logon:
Like other names used to identify files or to log on, a password may consist of as few as one or as many as eight characters. The first character must be a letter of the alphabet. Any remaining characters may be letters or numbers or a combination of them. The person in charge of your computer system may change or remove account passwords. The person in charge of an account, may change or remove group passwords. Unless you are one of these people, you cannot remove or change the passwords attached to an account or to a group. You may, however, use the PASSWORD command to change the password attached to your own user name. This log on puts you in the MYGROUP group of the ANYACCT account:
This log on puts you in some group of the ANYACCT account:
But in which group do you find yourself? Where that log on takes you depends upon two factors:
Recall that user names are attached to accounts. In turn, a home group may be attached to a user name. A home group may be any existing group within the account. When a home group is attached to a user name, that group becomes the default log on group for that user name. HELLO JOHN.ANYACCTReturn is an example of a default log on. The user JOHN did not specify the name of a group. As a result, this log on leads into the ANYACCT account and--by default--into the home group for the user JOHN. If the home group for user JOHN is the MTKG group, then this log on
is equivalent to--and has the same effect as--this log on:
If no home group has been assigned to JOHN, then HELLO JOHN.ANYACCT will fail. It is fairly common to designate one group within each account that is open to all users who log on to that account. This "shared" group is open to anyone who can log on to the account. A shared group provides a "place" for any programs and files that deserve to be available to all of the users of an account. A shared group belongs to all of the users of that account. Those users do not need to specify the password for the shared group when they log on to that group. Of course, they may still need to be able to enter the passwords for the user name and the account name.
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