LOOK-AT

@LOOK-AT  This command may be used to examine or modify memory locations and registers.  may be

When the  given has been checked for legality, and made available if mass storage segments are involved, the message READY is typed.
 * MEMORY: meaning user's virtual memory space. This is allowed for all users.
 * SEGMENT: A real-time program segment on mass storage may be reached. A segment number must be given as an additional parameter. This is allowed only for users RT and SYSTEM. A modification causes a permanent change of the specified location on the segment.
 * RTCOMMON: Locations on the common area for RT programs may be reached. This is allowed only for users RT and SYSTEM. A modification takes place in memory and leads only to a temporary change of the specified location. The next time SINTRAN is loaded the "old" values are retained.
 * IMAGE: Locations of the memory image of the resident part of SINTRAN III on mass storage can be reached. This is allowed only for user SYSTEM. A modification causes a permanent change of the specified location.
 * RESIDENT: Locations of the resident parts of SINTRAN III operating system can be reached. This is allowed only for user SYSTEM. A modification takes place in memory and leads only to a temporary change of the specified location. The next time the corresponding core-image is loaded to the memory, the "old" values are retained.

To examine a location, the octal address should be typed, followed by a slash (/). The octal contents will then be printed. The contents may now be changed by typing an octal value, followed by a carriage return. If only a cr, without a new value, is given, the contents remain unchanged and the contents of the next location are printed.

If an asterisk (*) is typed, the current address will be printed.

The contents of registers can be addressed in the same way, using a single letter to specify the register. The letters are: P, X, T, A, D, L, S, B. When a character not mentioned above is typed, the command is terminated and control will return to normal control mode.

If locations on mass storage sections are changed, the pages will be written out so that "patches" will be made permanent. Locations changed in the user's virtual memory or the resident part of the operating system are changed temporarily. They may be altered when loading a user program or reloading the system.