Browse Prior Art Database

Microcode Log Out to Fault Locate the Storage Distribution Frame

IP.com Disclosure Number: IPCOM000078956D
Original Publication Date: 1973-Apr-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 23K

Publishing Venue

IBM

Related People

Jones, DS: AUTHOR [+2]

Abstract

When an error occurs during the processing of data, a status indication of certain portions of storage is logged out to a special log-out data set for analysis by diagnostic routines. In that manner, it is hoped that maintenance of storage will be simplified for effective field replaceable unit isolation. However, multiple-bit failures make it impossible to successfully obtain valid log-out data and if a single-bit failure is propagated throughout storage, there is a high probability that such a massive single-bit failure will interact with scattered single-bit failures in the array (single-bit failures are left in the array for economic reasons), causing a multiple-bit failure in parts of the log-out region. If this should happen, a key log-out word may not be stored or fetched correctly.

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Microcode Log Out to Fault Locate the Storage Distribution Frame

When an error occurs during the processing of data, a status indication of certain portions of storage is logged out to a special log-out data set for analysis by diagnostic routines. In that manner, it is hoped that maintenance of storage will be simplified for effective field replaceable unit isolation. However, multiple- bit failures make it impossible to successfully obtain valid log-out data and if a single-bit failure is propagated throughout storage, there is a high probability that such a massive single-bit failure will interact with scattered single-bit failures in the array (single-bit failures are left in the array for economic reasons), causing a multiple-bit failure in parts of the log-out region. If this should happen, a key log- out word may not be stored or fetched correctly.

This arrangement provides a microorder and path for storing an assembled double word of log-out data into a CPU register, rather than into a memory location. The data path used is the same as the normal log-out path until the buffer bypass latch is reached. At this point, the microorder "bypass buffer" is executed, which, along with other appropriate microorders, will take any desired log-out word to the B register where it can be analyzed to determine the cause of failure. The log-out can be initiated by the microorder "start-log", and a counter can be set to determine the number of cycles from the start of the...