Browse Prior Art Database

Automatic IPL for Dual Processor Systems With Shared Common Direct-Access Storage Devices

IP.com Disclosure Number: IPCOM000042829D
Original Publication Date: 1984-Jun-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 3 page(s) / 43K

Publishing Venue

IBM

Related People

Baker, ED: AUTHOR

Abstract

A feature is described that eliminates the need for operator intervention for dual processors with shared DASD (direct-access storage device)/IPL (initial program load) devices during automatic IPL and IPL sequences. The feature is utilized in conjunction with processors such as the IBM Series/1 processor, and a programmable two channel switch (PTCS). In the drawings, the PTCS card 1 allows two asynchronous Series/1 Processors (CPUs) 2 and 3 to time-share common input/output (CIO) devices 4 and 5 under software control. Processor 3 has a private input/output (PIO) device 6 assigned to it and accessible only by it. Connectors 7-10 on card 1 are wired closed or open as shown for primary and alternate IPL functions.

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Automatic IPL for Dual Processor Systems With Shared Common Direct- Access Storage Devices

A feature is described that eliminates the need for operator intervention for dual processors with shared DASD (direct-access storage device)/IPL (initial program load) devices during automatic IPL and IPL sequences. The feature is utilized in conjunction with processors such as the IBM Series/1 processor, and a programmable two channel switch (PTCS). In the drawings, the PTCS card 1 allows two asynchronous Series/1 Processors (CPUs) 2 and 3 to time-share common input/output (CIO) devices 4 and 5 under software control. Processor 3 has a private input/output (PIO) device 6 assigned to it and accessible only by it. Connectors 7-10 on card 1 are wired closed or open as shown for primary and alternate IPL functions. The PTCS command architecture allows the processors to "switch" the CIO devices from one CPUs control to the other via a Request/Release software command mechanism. IPL functions for the Series/1 processors are described, for example, in the IBM manuals GA34-0152 "Principles of Operations" and GA34-0159 "4952 Processor Model C and Processor Features Description". A processor of this nature has an operator console with various switches and keys thereon. These include, for example: IPL Source: This switch selects the I/O device to be used for program loading. In the Primary position, the device that was pre-wired as the primary IPL is selected. In the Alternate position, the device that was pre-wired as the alternate IPL device is selected. Load: Pressing this key causes a system reset, and the IPL sequence is started. The Load indicator is turned on and remains on until the IPL sequence is completed. When the IPL is completed, instruction execution begins at location 0 on priority level 0. Mode:

This switch has the following positions: Auto IPL - In this position, an IPL is initiated after a successful power-on sequence. Bit 13 of the PSW (power status word) is set to indicate to the software that an automatic IPL was performed. In this mode, Stop instructions are treated as no...