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Initial Microcode Load Across Interfaces

IP.com Disclosure Number: IPCOM000099171D
Original Publication Date: 1990-Jan-01
Included in the Prior Art Database: 2005-Mar-14
Document File: 5 page(s) / 209K

Publishing Venue

IBM

Related People

Carlson, BA: AUTHOR [+3]

Abstract

A Command Information Word (CIW) provides for an Initial Microcode Load (IML) function to be tied a command code point that a control unit uses for that function. IML is the process of loading base code into control unit such that it can respond to normal commands the interface. The interface is either a 360/370 Serial I/O or a System 360/370 I/O Interface to Control Unit (OEMI). A problem with existing I/O and OEMI interfaces is that there are unused command codes for use in an IML process. the past, each control unit specified the particular code points and the operations associated with those points. This old assignment technique allowed control units to specify different functions for same given code point.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 34% of the total text.

Initial Microcode Load Across Interfaces

       A Command Information Word (CIW) provides for an Initial
Microcode Load (IML) function to be tied a command code point that a
control unit uses for that function.  IML is the process of loading
base code into control unit such that it can respond to normal
commands the interface.  The interface is either a 360/370 Serial I/O
or a System 360/370 I/O Interface to Control Unit (OEMI).  A problem
with existing I/O and OEMI interfaces is that there are unused
command codes for use in an IML process. the past, each control unit
specified the particular code points and the operations associated
with those points.  This old assignment technique allowed control
units to specify different functions for same given code point.
Also, there were no code points that had not been used by one control
unit or and, thus, none were available to be assigned in an process.
Described is a method of assigning architected code points to the
System 360/370 Serial I/O and the interfaces.

      An IML manager 10, shown in Fig. 1, is any element or of
elements that controls the IML process.  Examples elements are
channels, channel subsystems, operating or service processors.

      There are nine IML commands.  Six of these commands data flow
from control unit 20 to IML manager 10. commands are Read

                            (Image Omitted)

 Get CIWS, Get LID, Get Load, Read Extended
Sense, Control Unit Request.  Two commands provide data flow IML
manager 10 to control unit 20.  These commands are and Write Buffer.
One command provides no data  That command is Selfload.

      The number of commands that are required to be by control unit
20 depends on the type of unit and where the IML code is stored
within the  For example, if the loads are retrieved through the
operating system path, then the Get Load command is required.
Control unit 20 either requests IML code, IML code, or both.

      In order to solve the problem of providing IML for components,
the following requirements must be met:
 1.  All new control units, requiring IML via the
     interface (serial or OEMI), use the above-listed IML
     commands.
 2.  The solution must not affect existing control
     units.
 3.  There must be a method for IML manager 10 to
     distinguish between control units that require code and
     those that deliver code.
 4.  There must be a method for control unit 20 to
     report the command code point that is to be used for
     each IML command.

      SOLUTION TO REQUIREMENT 1.  All control units must with the IML
architecture.

      SOLUTION TO REQUIREMENTS 2, 3, and 4.  When a system powers up,
it issues a Sense ID to determine the and model of the control unit
20.  A control unit 20 does not support any of the architected IML
functions only type and model information.  Control unit 20 wants to
be involved with th...