Browse Prior Art Database

Programmable Variable Memory Configuration Control

IP.com Disclosure Number: IPCOM000037299D
Original Publication Date: 1989-Dec-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 3 page(s) / 49K

Publishing Venue

IBM

Related People

Datres, JH: AUTHOR [+2]

Abstract

Disclosed is a design that will permit memory configuration and interleave to be programmed at system initialization time, allowing run time changes as required, and will support both asymmetric MP (Multiprocessor) memory as well as memory increments of 1 BSM.

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Programmable Variable Memory Configuration Control

Disclosed is a design that will permit memory configuration and interleave to be programmed at system initialization time, allowing run time changes as required, and will support both asymmetric MP (Multiprocessor) memory as well as memory increments of 1 BSM.

The design is based on an array to hold the configuration data and interleave instructions. This same mechanism will permit memory to be re-assigned to get around large areas with errors, or to provide clean memory for Initial Program Load or to provide clean memory for the system area.

For illustration purposes assume the size of the configurable element is 4MB and that a cache line size is 512 bytes. To avoid having high usage blocks of data on just one side of an MP, the 4MB bands will be split into EVEN and ODD 4KB pages. That is, all of the EVEN pages in a 4MB block can be assigned in one place, and all of the ODD pages can be assigned in another place (other side). This effectively spreads the pages across both sides of the system. Also consider the address bits to be represented, as shown in Fig. 1.

The configuration logic and array are shown in Fig. 2.

The definition of each of the fields and their functions in

Fig. 2 are:

SID DEFINES MP SIDE.

2, 3, 4 are bits that will define which BSM is selected

if memory is serially interleaved. In this case the

address bits 20-22 remain unchanged. If the

interleave is 8 way, by line, then the absolute

address b...