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# Dynamic Main Storage Address to Location Mapping

IP.com Disclosure Number: IPCOM000099317D
Original Publication Date: 1990-Jan-01
Included in the Prior Art Database: 2005-Mar-14
Document File: 3 page(s) / 87K

IBM

## Related People

Blackmon, HL: AUTHOR [+2]

## Abstract

A logic circuit algorithm for associating a main address to a physical memory card location is It provides a continuous memory address range any combination of different-sized memory cards.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 53% of the total text.

Dynamic Main Storage Address to Location Mapping

A logic circuit algorithm for associating a main address
to a physical memory card location is  It provides a continuous
memory address range any combination of different-sized memory cards.

Memory card-size registers are initialized in a to indicate the
amount of memory on each card. are N number of memory cards and,
therefore, N number card size registers.  Solving the problem of
allowing any of memory cards is done by determining which card must
be accessed for a given address.  This of address to memory card
positions is viewed in two

The first step is the calculation of the accumulative address
through each memory card.  This maximum is called the range for that
memory card.  There is range value for each memory card in the
system.  This is performed once and used during system  The general
equation for calculating the ranges  = Range(N-1) + Card Size(N) N
indicates the card location.  When N=1, the of = 0.

The second step is to compare the address for a memory to each
of the card range values simultaneously.  A indicates if the address
is less than that card's value.  The first compare, where the address
is less the range value, indicates the memory card which the is
located on.  Example: For a 6-memory card system following
configuration:
Card Sizes:
Card location (1):   Card Size = 3 Megabytes.
Card location (2):   Card Size = 2 Megabytes.
Card location (3):   Card Size = 0 Megabytes, (no card)
Card location (4):   Card Size = 1 Megabytes.
Card location (5):   Card Size = 4 Megabytes.
Card l...