Browse Prior Art Database

Method of Providing Communications Support in the VM Control Program

IP.com Disclosure Number: IPCOM000121876D
Original Publication Date: 1991-Oct-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 2 page(s) / 96K

Publishing Venue

IBM

Related People

Hoffman, RW: AUTHOR [+2]

Abstract

Significantly less CPU instructions are required and greater throughput is provided by providing communications support in a new kind of virtual machine.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Method of Providing Communications Support in the VM Control Program

      Significantly less CPU instructions are required and
greater throughput is provided by providing communications support in
a new kind of virtual machine.

      The program (1) running in a virtual machine initiates a
request, for example, a request to send data, to the partner program
(13) by calling the CPI Communication interface (2).  The CPI Com
interface (2) runs as a CSL routine in CMS (3).  The CPI Com
interface (2) issues the corresponding APPC/VM interface (4)
function.  At this point the data being sent is still in the virtual
machine's storage.  The APPC/VM interface (4) notifies the
Communications Support (5) that there is data to receive. The
communications support (5) is dispatched as a new kind of virtual
machine.  The communications support (5) invokes the APPC/VM
interface (4) from CP to receive the sent data. The APPC/VM interface
(4) copies the data from the user virtual machine to the
communication support (5) virtual machine.  The communications
support (5) then locks the virtual pages and issues the SIO to the
370 processor (6) interface which causes the data to be transferred
through the I/O device (7).  The target system, in this case, another
370 processor (8), notifies the communications support (9) that data
has come in over the I/O device (7). The communications support (9)
locks some of its virtual pages and issues the appropriate I/O
commands to the 370 processor (8) to receive the data.  After the
data is received the pages are unlocked.  The communications support
(9) then calls the APPC/VM interface (10) to send the data on behalf
of the source program (1).  The APPC/VM interface (10) then notifies
CMS (11) that there is data to receive.  CMS (11) notifies the CPI
Com interface (12).  The CPI Com interface (12) then calls the
APPC/VM interface (10) to receive the data.  The APPC/VM interface
(10) copies the data from the communication support (9) virtual
machine to the CPI Com interface (12) storage.  When the program (13)
is ready to receive more data it calls the CPI Com interface (12) and
is given the data.

 ...