Browse Prior Art Database

IPL With Programmable ROS Control

IP.com Disclosure Number: IPCOM000103254D
Original Publication Date: 1990-Sep-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 1 page(s) / 54K

Publishing Venue

IBM

Related People

Hardell, WR, Jr: AUTHOR [+3]

Abstract

Disclosed is a means to control the ROS access time during IPL while the IPL code is running out of that ROS.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 69% of the total text.

IPL With Programmable ROS Control

      Disclosed is a means to control the ROS access time during IPL
while the IPL code is running out of that ROS.

      This method requires a control register in the hardware with
the ROS access time.  The ROS access time (in cycles) can be set by
software writing to the hardware control register.  This is desirable
because system performance will be impacted if the ROS accesses take
longer than the minimum ROS access time.  Also, if the hardware takes
less time than the minimum access time then the data from ROS may be
invalid.

      It is undesirable to have the ROS access time hard wired
because that access time would need to be set for 1 clock speed and 1
ROS access time.  If the access time were hard wired and the same
hardware were used in a system with a different cycle time or a
different ROS, then the hardware might be using an invalid or
inefficient access time.

      In this method, the hardware will start off with the maximum
ROS access time in the control register.  The first code in the ROS
will set the ROS access time in the control register to the optimum
value.  The access time could be coded in the ROS for one specific
cycle time or the ROS code might be able determine the cycle time
(this would depend on the processor) and set the configuration
register accordingly.

      If the CPU chips were used in a system with a different cycle
time then only the ROS code would need to be changed. The...