Browse Prior Art Database

Error Logging in a Data-Display Terminal

IP.com Disclosure Number: IPCOM000041924D
Original Publication Date: 1984-Mar-01
Included in the Prior Art Database: 2005-Feb-03
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Fredericksen, JK: AUTHOR [+5]

Abstract

A microprocessor-controlled CRT data-display terminal has a non-volatile read-write memory (NVRAM) containing a log of two-character codes indicating various types of errors which have occurred in the hardware or microcode. When the terminal is in its power-up diagnostic mode (Fig. 1), detection of an error by diagnostic microcode causes the error code to replace the oldest entry in a stack of ten entries. Then a pointer is updated to point to the next oldest entry. In an off-line mode (Fig. 2) depression of a code-display keyboard key enters a null code into the stack, then displays the error codes in the stack entries on the CRT. The null entry provides a separator dividing error codes logged before the previous log display from those logged afterward.

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Error Logging in a Data-Display Terminal

A microprocessor-controlled CRT data-display terminal has a non-volatile read- write memory (NVRAM) containing a log of two-character codes indicating various types of errors which have occurred in the hardware or microcode. When the terminal is in its power-up diagnostic mode (Fig. 1), detection of an error by diagnostic microcode causes the error code to replace the oldest entry in a stack of ten entries. Then a pointer is updated to point to the next oldest entry. In an off-line mode (Fig. 2) depression of a code-display keyboard key enters a null code into the stack, then displays the error codes in the stack entries on the CRT. The null entry provides a separator dividing error codes logged before the previous log display from those logged afterward. This allows a customer engineer to determine which errors have occurred since the last time the terminal was repaired. The log can be cleared by displaying it repeatedly until it is filled with null entries.

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