The History of Computer Storage Innovation from 1928 to Today
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Media Draft Appendix
Media Draft Appendix October, 2001 P C Hariharan Media Historical evidence for written records dates from about the middle of the third millennium BC. The writing is on media1 like a rock face, cave wall, clay tablets, papyrus scrolls and metallic discs. Writing, which was at first logographic, went through various stages such as ideography, polyphonic syllabary, monophonic syllabary and the very condensed alphabetic systems used by the major European languages today. The choice of the medium on which the writing was done has played a significant part in the development of writing. Thus, the Egyptians used hieroglyphic symbols for monumental and epigraphic writing, but began to adopt the slightly different hieratic form of it on papyri where it coexisted with hieroglyphics. Later, demotic was derived from hieratic for more popular uses. In writing systems based on the Greek and Roman alphabet, monumental writing made minimal use of uncials and there was often no space between words; a soft surface, and a stylus one does not have to hammer on, are conducive to cursive writing. Early scribes did not have a wide choice of media or writing instruments. Charcoal, pigments derived from mineral ores, awls and chisels have all been used on hard media. Cuneiform writing on clay tablets, and Egyptian hieroglyphic and hieratic writing on papyrus scrolls, permitted the use of a stylus made from reeds. These could be shaped and kept in writing trim by the scribe, and the knowledge and skill needed for their use was a cherished skill often as valuable as the knowledge of writing itself. -
Magnetic Recording and Readout Memory
SNS college of Technology Coimbatore-641 035 MAGNETIC RECORDING AND READOUT MEMORY Nowadays, large number of information are stored in (or) retrieved from the storage devices, by using devices is magnetic recording heads and they function according to the principle of magnetic induction. Generally Ferro or Ferrimagnetic materials are used in the storage devices because in this type of materials only the magnetic interaction between only two dipoles align themselves parallel to each other. Due to this parallel alignment even if we apply small amount of magnetic field, a large value of magnetization is produced. By using this property information are stored in storage devices. In the storage devices, the recording of digital data (0‟s and 1‟s) depends upon the direction of magnetization in the medium. Magnetic parameters for Recording 1. When current is passed through a coil, a magnetic field is induced. This principle called “Electromagnetic Induction” is used in storage devices. 2. The case with which the material can be magnetized is another parameter. 3. We know the soft magnetic materials are the materials which can easily be magnetized and demagnetized. Hence a data can be stored and erased easily. Such magnetic materials are used in temporary storage devices. 4. Similarly, we know hard magnetic materials cannot be easily magnetized and demagnetized. So such magnetic materials are used in permanent storage devices. 5. In soft magnetic materials, the electrical resistance varies with respect to the magnetization and this effect is called magneto-resistance. This parameter is used in specific thin film systems. 19PYB102 & PHYSICS OF MATERIALS AND PHOTONICS D.SENGOTTAIYAN /AP/PHYSICS Page 1 SNS college of Technology Coimbatore-641 035 The magnetic medium is made of magnetic materials (Ferro or Ferric oxide) deposited on this plastic. -
Dual Digital Audio Tape Deck OWNER's MANUAL
» DA-302 Dual Digital Audio Tape Deck OWNER’S MANUAL D00313200A Important Safety Precautions CAUTION: TO REDUCE THE RISK OF ELECTRIC SHOCK, DO NOT REMOVE COVER (OR BACK). NO USER-SERVICEABLE PARTS INSIDE. REFER SERVICING TO QUALI- Ü FIED SERVICE PERSONNEL. The lightning flash with arrowhead symbol, within equilateral triangle, is intended to alert the user to the presence of uninsulated “dangerous voltage” within the product’s enclosure ÿ that may be of sufficient magnitude to constitute a risk of electric shock to persons. The exclamation point within an equilateral triangle is intended to alert the user to the pres- ence of important operating and maintenance (servicing) instructions in the literature Ÿ accompanying the appliance. This appliance has a serial number located on the rear panel. Please record the model number and WARNING: TO PREVENT FIRE OR SHOCK serial number and retain them for your records. Model number HAZARD, DO NOT EXPOSE THIS Serial number APPLIANCE TO RAIN OR MOISTURE. For U.S.A Important (for U.K. Customers) TO THE USER DO NOT cut off the mains plug from this equip- This equipment has been tested and found to com- ment. If the plug fitted is not suitable for the power ply with the limits for a Class A digital device, pur- points in your home or the cable is too short to suant to Part 15 of the FCC Rules. These limits are reach a power point, then obtain an appropriate designed to provide reasonable protection against safety approved extension lead or consult your harmful interference when the equipment is operat- dealer. -
Magnetic Storage- Magnetic-Core Memory, Magnetic Tape,RAM
Magnetic storage- From magnetic tape to HDD Juhász Levente 2016.02.24 Table of contents 1. Introduction 2. Magnetic tape 3. Magnetic-core memory 4. Bubble memory 5. Hard disk drive 6. Applications, future prospects 7. References 1. Magnetic storage - introduction Magnetic storage: Recording & storage of data on a magnetised medium A form of „non-volatile” memory Data accessed using read/write heads Widely used for computer data storage, audio and video applications, magnetic stripe cards etc. 1. Magnetic storage - introduction 2. Magnetic tape 1928 Germany: Magnetic tape for audio recording by Fritz Pfleumer • Fe2O3 coating on paper stripes, further developed by AEG & BASF 1951: UNIVAC- first use of magnetic tape for data storage • 12,7 mm Ni-plated brass-phosphorus alloy tape • 128 characters /inch data density • 7000 ch. /s writing speed 2. Magnetic tape 2. Magnetic tape 1950s: IBM : patented magnetic tape technology • 12,7 mm wide magnetic tape on a 26,7 cm reel • 370-730 m long tapes 1980: 1100 m PET –based tape • 18 cm reel for developers • 7, 9 stripe tapes (8 bit + parity) • Capacity up to 140 MB DEC –tapes for personal use 2. Magnetic tape 2014: Sony & IBM recorded 148 Gbit /squareinch tape capacity 185 TB! 2. Magnetic tape Remanent structural change in a magnetic medium Analog or digital recording (binary storage) Longitudinal or perpendicular recording Ni-Fe –alloy core in tape head 2. Magnetic tape Hysteresis in magnetic recording 40-150 kHz bias signal applied to the tape to remove its „magnetic history” and „stir” the magnetization Each recorded signal will encounter the same magnetic condition Current in tape head proportional to the signal to be recorded 2. -
A Tube for Selective Electrostatic Storage
The Selectron -- A Tube for Selective Electrostatic Storage We are engaged at the RCA Laboratories in the development of a storage tube for the inner memory of electronic digital computers. This work is a part of our collaboration with the Institute for Advanced Study in the development of a universal electronic computer. The present note describes briefly the principle of operation of the tube, which is still in its experimental stage. It is a summary of a paper presented at the "Symposium of Large Scale Calculating Machinery" at Harvard University on January 8, 1947; see MTAC, v.2, p. 22~238. The necessity of an inner memory in electronic digital computers has been realized by all designers. The high computing speed possible with electronic devices becomes useful only when sufficient intermediary results can be memorized rapidly to allow the automatic handling of long sequences of accurate computations which would be impractically lengthy by any other slower means. An ideal inner memory organ for a digital computer should be able to register in as short a writing time as possible any selected one of as many as possible on-off signals and be able to deliver unequivocally the result of this registration after an arbitrarily long or short storing time with the smallest possible delay following the reading call. The selectron is a vacuum tube designed in an attempt to meet these ideal requirements. In it, the signals are represented by electrostatic charges forcefully stored on small areas of an insulating surface. The tube comprises an electron source which bombards the entire storing surface. -
Digital Audio Tapes: Their Preservation and Conversion 1 Smithsonian Institution Archives Summer 2010
Digital Audio Tapes: Their Preservation and Conversion 1 Smithsonian Institution Archives Summer 2010 Digital Audio Tapes: Their Preservation and Conversion Susan Eldridge, Digital Services Intern Overview Digital Audio Tapes (DATs) are 4mm (or 3.81mm) magnetic tape cassettes that store audio information in a digital manner. DATS are visually similar to compact audio cassettes, though approximately half the size, use thinner tapes, and can only be recorded on one side. Developed by Sony in 1987, DATs were quite popular in recording studios and were one of the first digital recording systems to become employed in archives in the late 1980s and 1990s due to their lossless encoding. Commercial use of DATs, on the other hand, never achieved the same success as the machines were expensive and commercial recordings were not available on DAT. Depending on the tape and machine used, DATs allow four different sampling modes: 32 kHz at 12 bits quantization, and 32 kHz, 44.1 kHz, and 48 kHz at 16 bits.1 All support two-channel stereo recording. Some of the later DATs (before being discontinued) could extend the bit-depth to 24 and up to 98 kHz, however, these tapes were likely rarely playable on other models.2 DATs can run between 15 and 180 minutes in length, one again depending on the tape and quality of the sampling. Unlike some other digital media, DATs do not use lossy data compression, which is important in the lossless transferring of a digital source to a DAT. Sony ultimately discontinued the production of DAT machines in 2005.3 Composition A digital magnetic tape is composed of two primary layers: the base film and magnetic layer. -
Investigation of Fast Initialization of Spacecraft Bubble Memory Systems Karen T, Looney, Charles D, Nichols., and Paul J, Hayes
N 8 4 - 2 7 0 7 7 NASA Technical Memorandum 85832 INVESTIGATION OF FAST INITIALIZATION OF SPACECRAFT BUBBLE MEMORY SYSTEMS KAREN T, LOONEY, CHARLES D, NICHOLS., AND PAUL J, HAYES JUNE 1984 NASA National Aeronautics and Space Administration Langley Research Center Hampton, Virginia 23665 SUMMARY Bubble domain technology offers significant improvement in reliability and functionality for spacecraft onboard memory applications. In considering potential memory system organizations, minimization of power in high capacity bubble memory systems necessitates the activation of only the desired portions of the memory. In power strobing arbitrary memory segments, a capability of fast turn-on is required. Bubble device architectures, which provide redundant loop coding in the bubble device, limit the initialization speed. Alternate initialization techniques have been investigated to overcome this design limitation. An initialization technique using a small amount of external storage has been demonstrated, using software written in 8085 assembly language and PL/M. ' This technique provides several orders of magnitude improvement over the normal initialization time. INTRODUCTION Bubble memory systems are quickly becoming a preferred storage medium in environments where a non-volatile storage medium is required. The utilization of a bubble storage system offers the benefits of increased reliability, reduced maintainance, and permanent data integrity. The implementaton of large bubble memory systems in spacecraft applications requires that the memory modules be power strobed for the conservation of the available energy resources. Each time a module is turned on for use it must be initialized to code the redundant loop information of the selected bubble devices into the bubble controller. Present structures of bubble systems dictate that a faster initialization procedure is needed in order to capitalize on the advantages offered by a bubble memory system. -
Digital Audio and Compact Disc Technology Second Edition Edited by Luc Baert, Luc Theunissen and Guido Vergult, Sony Service Centre (Europe)
Digital Audio and Compact Disc Technology Second edition Edited by Luc Baert, Luc Theunissen and Guido Vergult, Sony Service Centre (Europe) NEWNES Newnes An imprint of Butterworth-Heinemann Ltd Linacre House, Jordan Hill, Oxford OX2 8DP *1§* PART OF REED INTERNATIONAL BOOKS OXFORD LONDON BOSTON MUNICH NEW DELHI SINGAPORE SYDNEY TOKYO TORONTO WELLINGTON First published 1988 Second edition 1992 © Sony Service Centre (Europe) NV 1988, 1992 All rights reserved. No part of this publication may be reproduced in any material form (including photocopying or storing in any medium by electronic means and whether or not transiently or incidentally to some other use of this publication) without the written permission of the copyright holder except in accordance with the provisions of the Copyright, Designs and Patents Act 1988 or under the terms of a licence issued by the Copyright Licensing Agency Ltd, 90 Tottenham Court Road, London, England W1P 9HE. Applications for the copyright holder's written permission to reproduce any part of this publication should be addressed to the publishers British Library Cataloguing in Publication Data Digital Audio and Compact Disc Technology. - 2Rev. ed I. Baert, Luc 621.38932 ISBN 0 7506 0614 2 Printed and bound in Great Britain by Thomson Litho Ltd, East Kilbride, Scotland Preface The past century has witnessed a number of inventions and developments which have made music regularly accessible to more people than ever before. Not the least of these were the inventions of the conventional analog phono- graph and the development of broadcast radio. Both have undergone successive changes or improvements, from the 78 rpm disc to the 33V3 rpm disc, and from the AM system to the FM stereo system. -
Digital Audio Systems
Digital Audio Systems While analog audio produces a constantly varying voltage or current, digital audio produces a non-continuous list of numbers. The maximum size of the numbers will determine the dynamic range of the system, since the smallest signal possible will result from the lowest order bit (LSB or least significant bit) changing from 0 to 1. The D/A converter will decode this change as a small voltage shift, which will be the smallest change the system can produce. The difference between this voltage and the voltage encoded by the largest number possible (all bits 1’s) will become the dynamic range. This leads to one of the major differences between analog and digital audio: as the signal level increases, an analog system tends to produce more distortion as overload is approached. A digital system will introduce no distortion until its dynamic range is exceeded, at which point it produces prodigious distortion. As the signal becomes smaller, an analog system produces less distortion until the noise floor begins to mask the signal, at which point the signal-to-noise ratio is low, but harmonic distortion of the signal does not increase. With low amplitude signals, a digital system produces increasing distortion because there are insufficient bits available to accurately measure the small signal changes. There is a difference in the type of interference at low signal levels between analog and digital audio systems. Analog systems suffer from thermal noise generated by electronic circuitry. This noise is white noise: that is, it has equal power at every frequency. It is the “hiss” like a constant ocean roar with which we are so familiar. -
Recording Sound Effects
PRODUCING GREAT SOUND for DIGITAL VIDEO Jay Rose EXPERT SERIES San Francisco, CA • New York, NY • Lawrence, KS Published by CMP Books an imprint of CMP Media LLC Main office: 600 Harrison Street, San Francisco, CA 94107 USA Tel: 415-947-6615; fax: 415-947-6015 www.cmpbooks.com email: [email protected] Designations used by companies to distinguish their products are often claimed as trademarks. In all instances where CMP is aware of a trademark claim, the product name appears in initial capital letters, in all capital letters, or in accordance with the vendor’s capitalization preference. Readers should contact the appropriate companies for more complete information on trademarks and trademark registrations. All trademarks and registered trade- marks in this book are the property of their respective holders. Copyright © 2003 by Jay Rose, except where noted otherwise. Published by CMP Books, CMP Media LLC. All rights reserved. Printed in the United States of America. No part of this publication may be reproduced or distrib- uted in any form or by any means, or stored in a database or retrieval system, without the prior written permission of the publisher; with the exception that the program listings may be entered, stored, and executed in a computer system, but they may not be reproduced for publication. The publisher does not offer any warranties and does not guarantee the accuracy, adequacy, or completeness of any information herein and is not responsible for any errors or omissions. The publisher assumes no liability for damages resulting from the use of the information in this book or for any infringement of the intellectual property rights of third parties that would result from the use of this information. -
PDF 12 Kb (OCR'd)
An Interview with HERMAN GOLDSTINE -- OH 18 Conducted by Nancy Stern on 11 August 1980 Charles Babbage Institute The Center for the History of Information Processing University of Minnesota [excerpts] Page 36 STERN: Can you give me some information on the Selectron? GOLDSTINE: Yes, the selectron tube? Right. The thing that RCA was supposed to contribute to the project was memory tube. Rajchman -- Jan Rajchman -- you've probably got his name--worked under Vladimir Zworykin at RCA Research in Princeton. Zworykin and he decided at the beginning that it would be best to store information in the phosphor of the cathode ray tube. (You store a charge.) They decided that it would not be wise to try to switch the beam to a given point by analog circuits which is the way a television set does. But that instead, you should put into the cathode ray tube a grid which had 4,096 windows, all of which were available. They ultimately cut it down to 512 or whatever the size was that they finally arrived at--windows. One and only one window could be opened at any one time. The way the beam worked was that it just sprayed electrons out, more or less hitting the whole wall, the whole wall being filled with windows, and trying to go through whatever window would let the current go through. The beam therefore could only go through whichever window was open. Now, that was the concept. The windows were opened by suitable electrical impulses on each of two wires, and were closed by the same mechanism. -
SAA Early Born Digital Formats
Early born-digital audio formats (Slide Notes) Compiled by George Blood SLIDE 1 GBA logo SLIDE 2 GBA logo audio SLIDE 3 GBA audio video SLIDE 4 SSA logo SLIDE 5 SSA presents SLIDE 6 Title Slide Early born-digital audio formats SLIDE 7 First Commercially Available Formats: PCM-1 PCM-10 PCM-F1 PCM1600/1610/1630 ...DAT As a practical matter, I'll be speaking about the last three of these early formats. Unless you work for a record label, it is highly unlikely you'll see PCM-1 or PCM-10 tapes. In 25 years I've only seen one PCM-10. (Hint, it plays like a PCM1600, but uses a PCM-F1 decoder). SLIDE 8 citation: "The Dawn of Commercial Digital Recording" ARSC Journal, Tom Fine There are earlier formats, mostly based on data recorders or custom hardware. For an excellent introduction to this Jurassic period of digital recording, see Tom Fine's article in the Spring 2008 issue of the Journal of the Association for Recorded Sound Collections. SLIDE 8b Principles of Digital Audio, Ken Pohlman As with most materials we face in preservation, it helps to understand the properties of our quarry. I'm going to do a very brief introduction to digital audio. For anyone who wishes to dig deeper, I highly recommend this book. Ken's writing his extremely clear. You can look up individual topics, or read entire chapters. It is a standard desk reference at my facility. SLIDE 9a Quantization "The process of converting analog signals to digital." syn: digitization For our purposes, in preservation, we are talking about Pulse Code Modulation: PCM.