Browse Prior Art Database

Automatic Multiple Verify Write Function

IP.com Disclosure Number: IPCOM000106292D
Original Publication Date: 1993-Oct-01
Included in the Prior Art Database: 2005-Mar-20
Document File: 2 page(s) / 70K

Publishing Venue

IBM

Related People

Abbott, JW: AUTHOR [+5]

Abstract

The 'verify write' memory verification function is a method which allows microcode to perform memory verification tests more easily (less code) and quickly than it otherwise could. After initializing each location of the memory with a given data pattern and corresponding ECC byte, the microcode simply enables the 'verify write' function and issues another write of the same data that it previously wrote to each memory location. However, the hardware automatically performs a read from the memory instead of a write and compares the data bits and ECC bits read against the data the microcode thought it was once again writing to the memory. If any of the bits do not match, a corresponding bit(s) is set in the 'data verify' register, which keeps a cumulative record of miscompare errors on a bit-by-bit basis.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Automatic Multiple Verify Write Function

      The 'verify write' memory verification function is a method
which allows microcode to perform memory verification tests more
easily (less code) and quickly than it otherwise could.  After
initializing each location of the memory with a given data pattern
and corresponding ECC byte, the microcode simply enables the 'verify
write' function and issues another write of the same data that it
previously wrote to each memory location.  However, the hardware
automatically performs a read from the memory instead of a write and
compares the data bits and ECC bits read against the data the
microcode thought it was once again writing to the memory.  If any of
the bits do not match, a corresponding bit(s) is set in the 'data
verify' register, which keeps a cumulative record of miscompare
errors on a bit-by-bit basis.

      This function can be enhanced even more by implementing
multiple write/read capability within the hardware.  Any number of
registers can be established into which microcode can write data
patterns which are to be constant for an entire memory test.  After
loading these pattern registers and setting the enable bit(s) to put
the hardware into the automatic 'verify write' mode, the microcode
performs a write operation to the location it wishes to test (the
data used is ignored).  The hardware automatically latches up the
address being accessed, writes the data stored in the first pattern
register to the memory location, then reads back the same memory
location and compar...