System for deriving and testing mutual capability set after receiving updated capability from other processors and before requesting service information

• US 5,386,512 A
• Filed: 12/09/1993
• Issued: 01/31/1995
• Est. Priority Date: 07/19/1991
• Status: Expired due to Term

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Gainey, Charles W. Jr., Walsh, Kathleen M., Crisman, Mary B., Hughes, Duane C., Day, Arthur M., Greenstein, Paul G., Rodell, John T., Daly, James C.
• Primary Examiner(s): Lee, Thomas C.
• Assistant Examiner(s): Meky, Moustafa M.
• Application Number:
  US08/164,658
• Time in Patent Office: 418 Days
• Field of Search: 395/200, 395/375, 395/800, 364/252.5, 364/264.6, 364/264.7, 364/940.81, 364/937, 364/947.4
• US Class Current: 709/228
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

A dynamic capability exchange mechanism permits two processing entities to notify each other of initial properties, or processing capabilities, as well as subsequent changes to those properties or capabilities. Before requesting a service, or function, of the other entity, one entity consults a mutual characteristic field (constructed from the current properties, or characteristics) to determine if the service, or function, is jointly available. A transport layer, acting as the communication mechanism between the two entities, provides for bidirectional communications between entities including a Control Program and a Service Call Logical Processor. The transport layer provides multiplexing, priority, failure, pacing, and buffer spanning support.

Claims

1. An apparatus for communicating dynamic changes in capabilities of processors for use in a data processing system comprising two or more processors each having storage, said data processing system further comprising a communication path between a pair of the two or more processors, said apparatus comprising:

(a) current capability definitional means, within each of the two or more processors, for identifying a current set of processor functional capabilities associated with the processor containing said current set;

(b) detection means, within each of the two or more processors, for detecting a change to said current set of processor functional capabilities and updating said current capability definitional means, creating an updated current capability definitional means;

(c) communication means, invoked by said detection means, for communicating a copy (termed a communicated copy) of said updated current capability definitional means, associated with a sending processor of the pair of processors, from said sending one to a receiving one of the pair of processors, using the communication path;

(d) mutual capability identification means, within the receiving one of the pair of processors, for identifying, in a mutual capability definitional mask, a derived mutual processing functional capability set by combining said current capability definitional means associated with said receiving processor with said communicated copy of said updated current capability definitional means associated with said sending processor, so that each element of said mutual capability definitional mask, if "on" after said combining, identifies a particular processing functional capability which may be requested by one and performed by another of said pair of processors; and

(e) function request verification means, within the receiving one of the two or more processors, for testing said mutual capability definitional mask means to verify, before requesting a function of the sending processor, that the element of said mutual capability definitional mask associated with the function is "on" and negating the function request if the element is not "on".

2. The apparatus of claim 1 in which the sending one of the processors is a Service Call Logical Processor (SCLP), and the receiving one of the processors is a Central Processor having a Control Program.

3. The apparatus of claim 1 in which the sending one of the processors is a Central Processor having a Control Program, and the receiving one of the processors is a Service Call Logical Processor (SCLP).

4. The apparatus of claim 1 in which said current capability definitional means comprises a send mask, identifying one or more functions which may be requested by said each of the two or more processors, and a receive mask, identifying one or more functions which may be performed by said each of the two or more processors.

5. The apparatus of claim 4 further comprising function request verification means, within the receiving one of the two or more processors, for testing said mutual capability definitional mask means to verify that a to-be-requested function can be performed by said another processor of said pair of processor.

6. A method for operating a computer system, comprising a first and second processing entity, connected by a communication path, to detect and dynamically exchange processing capabilities, said method comprising the steps of:

(a) the first and second processing entity setting a first and second initial function value, respectively, in a first and second local function definition field, to indicate that one or more associated functions may be performed or requested each of said first and second local function definition fields comprising a plurality of bits and having a common function associated with identical bit positions;

(b) the first and second processing entity mutually communicating, over a communication means, the initial function value in their local function definition field and setting first and second local common function values, respectively, in local common function definition fields, each of the local common function values resulting from a logical ANDing of the first and second initial function values and indicating, if "on", that a particular associated function may be requested by one and performed by the other of the processing entities;

(c) the first processing entity detecting that one of the one or more associated functions can no longer be performed, and, in response, changing the first local function definition field to a changed first local function definition value;

(d) the first processing entity communicating the changed first local function value to the second processing entity over the communication means;

(e) the second processing entity receiving the changed first local function value from the first processing entity and, in response, modifying the second local common function value to a modified local common function value; and

(f) the second processing entity, requiring the associated function of the first processing entity, testing the modified local common function value and negating a request of the associated function by the first processing entity, in response to the modified local common function value.

7. The method of claim 6 in which the first processing entity is a processor having a Control Program, and the second processing entity is a Service Call Logical Processor.

8. The method of claim 6 in which the first processing entity is a Service Call Logical Processor, and the second processing entity is a processor having a Control Program.