Hi Al, Do you happen to have copies of the following IBM doc available? This is all I/O related, not sure if it's from the 370 days or later. MVS/ESA Component Diagnosis and Logic: EXCP Processor (LY28-1477) LY28-1487 LY28-1488 LC28-1166-5 I noticed you've added a bunch of great IBM doc recently in addition to all the other great IBM doc you have been hosting. THANK YOU for your site and all the great work you are doing!