Once a THEOS user accounting structure has been established, the only way that any files or programs can be accessed is by logging on to an account. If no accounting structure is present, these commands have no meaning because no accounts exist to LOGON to or LOGOFF from. LOGON/LOGOFF are complementary commands, and they will be discussed together. These commands have no privilege level associated with them.
The LOGOFF Command
When the LOGOFF command is executed, a series of events occur:
• If accounting history is being used, a history record is written to the ACCOUNT.HISTORY file.
• Any peripherals attached (via the ATTACH command) to the system by the currently logged account are detached.
• Control of the system is transferred to the LOGON command.
The format of the LOGOFF command is:
LOGOFF
The LOGON Command
When a user accounting structure exists in an THEOS system, you will be prompted to "Logon please:" after booting the system or after logging off of a particular account.
The format of the LOGON command is:
LOGON ACCOUNT NAME
In order to accomplish a successful logon, type the name of the specific account name you wish to logon to. When this command is executed, a series of events occurs:
• You are automatically logged off any account you are
• When the account name is found in the SYSTEM.AC-COUNT file and a password has been specified, TH EOS will respond: "Password?" When a password is entered, it is not displayed on the screen. A series of asterisks is used to prevent others from discovering the password.
• If the password is incorrect you are returned to the
"Logon please:" message.
• If accounting history is being used, a record indicating the logon is written to the ACCOUNT.HISTORY file.
• The THEOS SYSTEM.ERRMSG file is searched for messages 99 through 102 which are displayed if found.
These are usually messages entered by the hardware manufacturer which describe the type of hardware being used. These messages can be changed. See chapter 5 for instructions on how to enter these messages.
• The system disk is searched for a file called SYSTEM.-LOGON; its contents are displayed if found. These messages may include user instructions on what to do after successful logon. See chapter 5 for details how to enter these messages.
• The logon date and time are displayed on the screen.
At this point, successful logon has been accomplished. Although a number of steps are involved in the logon process, all steps are exe-cuted in less than two or three seconds:
After a successful logon has been accomplished, a search of all attached disks and their directories is made for an EXEC program with the file description of ACCOUNTNAME.EXEC, where the AC-COUNTNAME is the account onto which logon was requested. For example, if you requested to logon to USERl, THEOS would conduct a search for an EXEC called USERl. This special program called USERl might take you to a menu (another EXEC) which will make your THEOS system menu driven. More examples are provided in the EXEC tutorial.
116 THEOS User's Handbook
Note: If a successful logon has not been accomplished in three tries, the system automatically hangs and must be rebooted. This is a built in safety feature of THEOS designed to prevent users from gaining unauthorized access to the computer.
USING THE LOGON/LOGOFF COMMANDS
U sing these commands is simple and straightforward. No options are associated with them.
Example 1:
LOGOFF <RETURN>
Logoff at 13:45:21, on 12/17/84 Logon please:
This example illustrates the logoff procedure from the THEOS prompt. As shown, the user is automatically returned to the "Logon please:" message.
Example 2:
Logon please:USER2<RETURN> ~
Password?******* <RETURN>
Logon at 13:46:00, on 12/17/84
>
This example shows how to logon to an account with a password.
Note the series of asterisks THEOS displays in place of the actual password.
Example 3:
>L USER4 <RETURN>
Logon at 14:00:00, on 12/17/84
>
In this case when a request is made to logon to a new account, USER4, THEOS performs an automatic logoff before logging on to
the new account. If an account called USER4 is not found, an
"account not found" message is displayed on the screen, and the user is returned to the prompt logged onto the original account.
Example 4:
'logon please:U5ER7,******* <RETURN ~ Logon at 15:45:32, on 12/17/84
~> ~
This example illustrates logging on to a new account which has a password. Note that the Password? prompt is bypassed because the password was entered as part of the command line. This syntax only works if a logoff has been performed first and the "Logon please:"
message is displayed on the screen.
Summary
The LOGON / LOGOFF commands are the only means of access-ing THEOS programs that belong to user accounts. After an account-ing structure has been established, THEOS will request the user to
"Logon please:"afterthe system has been booted. If the user does not type in an account that exists after three tries, THEOS assumes that the user is unauthorized and hangs the system. When a user is finished with the system, it is recommended that the LOGOFF command be exe-cuted to ensure an orderly exit from the system.