Bill Fairchild wrote: At some time later, IBM also added a special protection feature for bytes 512-2047 of page 0. This feature, described in the Principles of Operation, and which is also both hardware and software, causes a program interrupt by any attempt for a non-key-0 program to fetch any storage in the first virtual 2K, where many register save areas are located, except for bytes 0-511, which may be fetched by a non-key-0 program. This allows the normal program to do a L instruction at location 16, which is where the address of the CVT is located. If you try to display bytes 0-511 with TSO, you should be able to, but not bytes 512-2047. And you can display bytes 2048-4095 with TSO.
Close, But not right. It is the 2nd 2K, bytes 2048-4095, that have this special attribute. Peter Relson z/OS Core Technology Design ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
