Browse Prior Art Database

Control Program Paging to Handle Conversational Monitor System File Data

IP.com Disclosure Number: IPCOM000037367D
Original Publication Date: 1989-Dec-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 2 page(s) / 58K

Publishing Venue

IBM

Related People

DeForest, TN: AUTHOR

Abstract

A direct access storage device (DASD) works by serially recording data on a magnetic disk in concentric magnetic rings, called tracks, which are created on the disk's surface by read/write heads. Each track is subdivided into records. This setup is illustrated in Fig. 1. There are multiple levels of disks which form cylinders of data. Data entered on the disks is located by accessing through a numbering system using cylinder number, track number and record number. (Image Omitted)

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Control Program Paging to Handle Conversational Monitor System File Data

A direct access storage device (DASD) works by serially recording data on a magnetic disk in concentric magnetic rings, called tracks, which are created on the disk's surface by read/write heads. Each track is subdivided into records. This setup is illustrated in Fig. 1. There are multiple levels of disks which form cylinders of data. Data entered on the disks is located by accessing through a numbering system using cylinder number, track number and record number.

(Image Omitted)

Changing the way in which Conversational Monitor System (CMS) DASD records are numbered makes it possible for Control Program (CP) to access CMS data records with the existing CP paging mechanism. This allows storing of data normally accessed as page images, such as shared segments, in CMS files and has a CMS program manage them. When these page images are required by CP, it is a matter of setting up the paging control blocks to point directly to the CMS file data and let normal page references to this data cause the CP paging logic to page them in. This sends the request directly to the paging system, reducing the overhead involved in satisfying the request.

Currently, CMS DASD records are numbered sequentially within a track and CP records are numbered sequentially across tracks and within a cylinder. This comparison is shown in Fig. 2. To make the above scheme work, the CMS records must be renumbered within each...