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Multi-Access Spool for Virtual Machine/ System Product

IP.com Disclosure Number: IPCOM000049246D
Original Publication Date: 1982-Apr-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 4 page(s) / 37K

Publishing Venue

IBM

Related People

Buco, WM: AUTHOR [+2]

Abstract

A multi-access simultaneous peripheral operations on-line SPOOL(MAS) implementation added to the IBM Virtual Machine/System Product (VM/SP) (1) to support the access of SPOOL files in a loosely coupled VM/SP configuration is described. From 2 to 8 VM/SP systems are coupled by shared direct-access storage device (DASD) and communication links. SPOOL files can be accessed from any of the VM/SP systems in the loosely coupled configuration by either the user or s VM/SP function, such as a printer task. Multi-access spool (MAS) manages and extends the access of SPOOL files between VM/SP systems. This design is intended to contribute to a future objective of a single VM/SP system image. MAS is an experimental system.

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Multi-Access Spool for Virtual Machine/ System Product

A multi-access simultaneous peripheral operations on-line SPOOL(MAS) implementation added to the IBM Virtual Machine/System Product (VM/SP) (1) to support the access of SPOOL files in a loosely coupled VM/SP configuration is described. From 2 to 8 VM/SP systems are coupled by shared direct-access storage device (DASD) and communication links. SPOOL files can be accessed from any of the VM/SP systems in the loosely coupled configuration by either the user or s VM/SP function, such as a printer task. Multi-access spool (MAS) manages and extends the access of SPOOL files between VM/SP systems. This design is intended to contribute to a future objective of a single VM/SP system image. MAS is an experimental system.

Multi-Access SPOOL Benefits: A remote spooling communications subsystem (RSCS) (2) is currently used to send copies of SPOOL files to other remote or local VM/SP systems. Each SPOOL file that RSCS sends between VM/SP systems involves the reading of the file, the transmission of the data, and the creation of a new file on the targeted system. MAS sends a control block associated with the SPOOL file to accomplish the same effect. The shared DASD provides each VM/SP system access to the single copy of a SPOOL file's data. MAS provides an efficient technique to control the access of files within the loosely coupled configuration.

MAS provides the users with a single logical view of all the SPOOL files in the loosely coupled VM/SP configuration. A user can log on any of the VM/SP systems to access his SPOOL files. SPOOL files may be transferred between users without regard to the VM/SP system the receiving user logs on.

All the SPOOL hardware devices (printers, punches and card readers) are logically connected to each VM/SP system. MAS provides additional ways to configure and reconfigure the SPOOL hardware without affecting system or user software. The user need not be informed of the way the SPOOL hardware is physically connected. All SPOOL devices, for example, could be physically connected to just one system, as shown in the drawing. Additional software to support the asymmetrically configured SPOOL hardware is not required. The users direct files to a SPOOL output device the same way on each system. MAS utilizes better the existing SPOOL devices and reduces the duplication of these devices on each system.

Multi-Access SPOOL Design: The number of spool file blocks (SFBs) that may exist in a loosely coupled configuration may easily exceed 9900 as the number of systems increase. The total main storage for each copy SFB will increase only when a system receives a copy SFB. This design attempts to minimize the number of copy SFBs sent to systems in the loosely coupled configuration by using the following techniques. When an original SFB is closed and placed on the input queue and the owner is logged on the same system, a copy SFB is not sent to any other system. There is jus...