Browse Prior Art Database

IMPLEMENTING MASS STORAGE FACLITIES IN OPERATING SYSTEMS

IP.com Disclosure Number: IPCOM000131272D
Original Publication Date: 1978-Feb-01
Included in the Prior Art Database: 2005-Nov-10
Document File: 9 page(s) / 37K

Publishing Venue

Software Patent Institute

Related People

Donald L. Boyd: AUTHOR [+3]

Abstract

The appearance in the commercial marketplace of on-line auxiliary memory devices with very large capacities has resulted in several new and interesting problems. These problems include new applications of the devices (generally called mass storage facilities or MSF's) for storage of on-line data, the need for new data structures organized about the physical characteristics of the MSF, problems in performance, enhancement of automatic device and data control, enhancement of automatic memory management systems, increased concern for data integrity, and the continuing need for more memory protection capability. To meet these problems, several practical implementation approaches have been considered for the addition of mass storage subsystems to host systems. These approaches have made apparent the need for more research in the areas of memory management and scheduling policies. Memory technology is developing at a rapid rate, while practical implementations are impeded by many problems. The article outlines three of these approaches to implementation from the point of view of automatic auxiliary memory management systems. Finally, a simple management model is proposed and some open research problems are indicated.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 10% of the total text.

Page 1 of 9

THIS DOCUMENT IS AN APPROXIMATE REPRESENTATION OF THE ORIGINAL.

This record contains textual material that is copyright ©; 1978 by the Institute of Electrical and Electronics Engineers, Inc. All rights reserved. Contact the IEEE Computer Society http://www.computer.org/ (714-821-8380) for copies of the complete work that was the source of this textual material and for all use beyond that as a record from the SPI Database.

IMPLEMENTING MASS STORAGE FACLITIES IN OPERATING SYSTEMS

Donald L. Boyd

Honeywell Corporate Technology Center

Introduction

The appearance in the commercial marketplace of on-line auxiliary memory devices with very large capacities has resulted in several new and interesting problems. These problems include new applications of the devices (generally called mass storage facilities or MSF's) for storage of on-line data, the need for new data structures organized about the physical characteristics of the MSF, problems in performance, enhancement of automatic device and data control, enhancement of automatic memory management systems, increased concern for data integrity, and the continuing need for more memory protection capability.

To meet these problems, several practical implementation approaches have been considered for the addition of mass storage subsystems to host systems. These approaches have made apparent the need for more research in the areas of memory management and scheduling policies. Memory technology is developing at a rapid rate, while practical implementations are impeded by many problems.

The article outlines three of these approaches to implementation from the point of view of automatic auxiliary memory management systems. Finally, a simple management model is proposed and some open research problems are indicated.

Mass storage facility characteristics

Most prominent among available MSF's are the Control Data 38500,' the IBM 3850,Z and the Ampex Terabit Memory (TBM).34 The TBM is an outgrowth of videotape technology, and therefore its physical characteristics differ from those of the CDC and IBM devices, as do the problems it raises and the approaches to these problems. However, both latter devices consist of a very large number of tape cartridges residing in a "cell-structured" library. The cartridges' storage capacity ranges from 8 million to 50 million bytes, while the library of a single MSF holds from 2000 to 4720 cartridges. A single system may have a MSF storage capacity of up to nearly 500 billion bytes of storage. Under program control, any cartridge may be removed from the library and moved to a read/write station, where it is mounted and made ready for access. This loading operating requires from 3 to 13 seconds, depending upon the device, the distance of the addressed cartridge cell from the read/write station, and the location of the accessing mechanism at the beginning of the cycle. Once the cartridge is mounted, the data transfer is very fast, comparable to that of disk or drum. Ho...