2023-01-09 https://drive.google.com/drive/folders/1YEyWEW164xPRJvAM3Rm_ZCL_nE9tR7Me?usp=share_link

This pinned post will have the latest revision of the best link to use – where you can browse the folders or simply search. Google doesn’t announce when they have deprecated a link so please use this instead if you’re having issues.

  1. Please open the folder ‘Scanned Book and Magazine Collection’ with the green icon – that is the main source of my files
  2. Search! Everything has been OCR’d via AppleVision or Tesseract 4 and is therefore easily indexed

Please consider donating via PayPal as a contribution to hosting costs and scanning equipment.

Google Drive has a range of features that keep me choosing them as my paid hosting platform. This blog post aims to be a site that highlights the new content uploaded to the main repository so visual learners can see what’s new. Unfortunately Google’s share API continues to change and breaks links from older blog posts. You can browse by Genre / Subject (the folder titles)

Featured post

Digital Computer Principles 2nd ed Burroughs Corporation

Shared here not just for the retro aesthetic (1969) but the contents holds up to today. It explains analogue electronics and how that relates to computer circuits then goes into fundamental design principles. Worth scrolling through, check out the section on computer character display on cathode ray (CRT) monitors for a clear summary of the 3 different technologies in use at the time.

Technical Training Department ISBN 07-009232X, believed to be expired copyright. Navigate the shared Google Drive link to folder Scanned Book Brochure and Magazine Collection -> General Vintage Computing Books file name Digital Computer Principles 2nd Burroughs Corporation Technical Training Department ISBN 07-009232X.pdf

This book is intended to provide an explanation of the basic principles of digital computers and the manner in which the basic building blocks are combined to provide small- and large-scale computing systems.
‘The text has undergone extensive revision and reorganization for the second edition. All references to vacuum-tube circuitry have been dropped,
and the introductory chapter on basic semiconductor device theory has been deleted. A more detailed analysis of computer organization has been presented, and new material on system control concepts and integrated
circuits added.
The book is divided into three parts:
Computer Fundamentals (Chapters 1 through 9)
II Computer and Peripherals (chapters 10 through 14)
III Programming and System Concepts (Chapters 15 through 18)

Part I provides an exposure to the fundamental concepts which govern the operation of the digital computer. It includes an introduction to com- puters, logic, numbering systems, Boolean algebra, magnetic device fundamentals, and transistor switching characteristics. The chapter on computer circuits presents circuit analyses of the basic circuits used in digital computers, while the chapter on computer elements shows how the
basic circuits are combined to provide larger functional groupings.
Part Il deals with the computer and the peripheral devices which are connected to it. The chapter on the basic computer presents the data flow within the computer and the interfaces which exist among the major
functional areas. A separate chapter is devoted to memory systems used with computing systems.
‘The chapters on peripheral devices and display systems provide an insight into the range of input/output devices used with the computing system, as well as into some of the operating characteristics of each device. Computer organization is discussed in a chapter which shows how the functional computer areas have been developed within the modularity concept.
Part III provides an introduction to programming and discusses some of the more advanced concepts used in computing system control.

Australiana – The Courier Mail Fun Club – Happy Birthday card (1989)

Shared here simply for future reference is a birthday card sent to children registered with the Courier Mail ‘Fun Club’. Post card sized and custom text imprinted on the back that was customised to the birthday boy or girl (redacted the name and date in Adobe Photoshop).

Considering the popularity of my ‘Dollarmites’ scan of the Commonwealth Bank’s deposit booklet for children, I figured let’s add another thing ‘to the internet’ that someone might enjoy remembering.

1200dpi scans available in the Scanned Book and Magazine folder then open Australiana

So what’s new, 23rd January edition (massive):

Your Computer. Literally the magazine Your Computer features heavily in January’s uploads with 131 magazines scanned (a personal best!). An Australian publication worthy of preservation as it consistently reported on industry news and supported all the ‘micros’ of the time e.g Microbee, Hitachi Peach, Apple II, IBM PC. Be sure to download at least a few editions to enjoy the time capsule that is the cutting edge of technology. Whether that be Mr. Les Bell writing in 1981 that Telecom tower in Canberra will lead to people earning a salary purely at home via computer terminal, or in 1985 where IBM announce they are partnering with People’s Republic of China to provide data centres and beat the Japanese to the market at the same time.

I have no doubt this~14,000 page upload will serve Australian enthusiasts and researchers or years to come. Each title has OCR applied via state of the art Apple Vision machine learning text recognition. Tesseract has served us well but I’m introducing Apple Vision to these and all future uploads.

In addition to the Your Computer scans, we have nostalgic catalogues from Dick Smith and Micro Educational; special issues of Scientific American and New Scientist plus many more listed below. Please consider donating to help cover expenses in this project or donating physical media for scanning.

Uploaded to the Shared Files on Google Drive
Australian PC User 1991-05.pdf
Budgetware 1991 issue 2.pdf
Cover ETI Computers and Computer Volume 4-1.jpg
Dick Smith Christmas Bargain Bulletin.pdf
Dick Smith Electronics 1st Edition 1991-1992 Catalogue.pdf
Dick Smith stock exchange catalogue 1985-06-01.pdf
ETI Book Sales – Summer Catalogue.pdf
ETI Computers and Computer Volume 4.pdf
Ericsson Personal Computer brochure.pdf
Freeware IBM and Compatible 1990 Catalogue.pdf
Imagineering Home Computer Software Price List 1984-09-22.pdf
Les Bell PC and MS-DOS Conference brochure.pdf
Les Bell Supporting Personal Computers conference brochure.pdf
MACBUSINESS – Your Computer feature.pdf
Manaccom Australia gaming ads
Micro-Educational Catalogue.pdf
New Scientist 1992-09-05.pdf
New Scientist 1992-10-17.pdf
New Scientist 1993-11-06.pdf
Rod Irving Electronics Computer and Electronics Catalogue 1990-04.pdf
Rod Irving Electronics catalogue.pdf
Scientific American 1992-01 processed.pdf
Scientific American 1992-02 processed.pdf
Scientific American 1993-10.pdf
Scientific American Specal Issue – Trends in Computer (rev2).pdf
Software Express Catalogue 1994.pdf
Software Express The Catalogue 1990.pdf
Software Express The Catalogue 1991.pdf
Software Express The Catalogue 1992.pdf
dLetter The Newsletter for dBase II and III users ND.pdf
dLetter The Newsletter for dBase II and III users.pdf
dLetter Vol 1 Issue 3.pdf

Australian Personal Computer 1988 1989-01.pdf
Australian Personal Computer 1988-07.pdf
Australian Personal Computer 1988-10.pdf
Australian Personal Computer 1988-11.pdf
Australian Personal Computer 1989-03.pdf
Australian Personal Computer 1989-05 Vol 10 No 5.pdf
Australian Personal Computer 1989-12.pdf
Australian Personal Computer 1993-11.pdf
Australian Personal Computer 1998-08.pdf

Last login: Mon Jan 23 13:39:08 on ttys000
Jeremy@MBP Your Computer % ls -R
Your Computer 1981-05 06.pdf
Your Computer 1981-07.pdf
Your Computer 1981-08.pdf
Your Computer 1981-09 10.pdf
Your Computer 1981-11.pdf
Your Computer 1981-12.pdf
Your Computer 1982-01.pdf
Your Computer 1982-02.pdf
Your Computer 1982-03.pdf
Your Computer 1982-04.pdf
Your Computer 1982-05.pdf
Your Computer 1982-06.pdf
Your Computer 1982-07.pdf
Your Computer 1982-08.pdf
Your Computer 1982-09.pdf
Your Computer 1982-10.pdf
Your Computer 1982-11.pdf
Your Computer 1982-12.pdf
Your Computer 1983-01 02.pdf
Your Computer 1983-03.pdf
Your Computer 1983-04.pdf
Your Computer 1983-05.pdf
Your Computer 1983-06.pdf
Your Computer 1983-07.pdf
Your Computer 1983-08.pdf
Your Computer 1983-09.pdf
Your Computer 1983-10.pdf
Your Computer 1983-11.pdf
Your Computer 1984 Yearbook 2.pdf
Your Computer 1984-01.pdf
Your Computer 1984-03.pdf
Your Computer 1984-04.pdf
Your Computer 1984-05.pdf
Your Computer 1984-06.pdf
Your Computer 1984-07.pdf
Your Computer 1984-08.pdf
Your Computer 1984-09.pdf
Your Computer 1984-10.pdf
Your Computer 1984-11.pdf
Your Computer 1984-12.pdf
Your Computer 1985-01.pdf
Your Computer 1985-02.pdf
Your Computer 1985-03.pdf
Your Computer 1985-04.pdf
Your Computer 1985-05 Bonus book of priceless programs.pdf
Your Computer 1985-05.pdf
Your Computer 1985-06.pdf
Your Computer 1985-07.pdf
Your Computer 1985-08.pdf
Your Computer 1985-09.pdf
Your Computer 1985-10.pdf
Your Computer 1985-11.pdf
Your Computer 1985-12.pdf
Your Computer 1986-01.pdf
Your Computer 1986-02.pdf
Your Computer 1986-03.pdf
Your Computer 1986-04.pdf
Your Computer 1986-05 Basic for Birdwatchers Part 1.pdf
Your Computer 1986-06 Basic for Birdwatchers Part 2.pdf
Your Computer 1986-06.pdf
Your Computer 1986-07.pdf
Your Computer 1986-08 (some ads removed).pdf
Your Computer 1986-09.pdf
Your Computer 1986-10.pdf
Your Computer 1986-11.pdf
Your Computer 1989-01.pdf
Your Computer 1989-02.pdf
Your Computer 1989-03.pdf
Your Computer 1989-04.pdf
Your Computer 1989-05.pdf
Your Computer 1989-06.pdf
Your Computer 1989-07.pdf
Your Computer 1989-08.pdf
Your Computer 1989-09 rev2.pdf
Your Computer 1989-10.pdf
Your Computer 1989-11.pdf
Your Computer 1989-12.pdf
Your Computer 1990-01.pdf
Your Computer 1990-02.pdf
Your Computer 1990-03.pdf
Your Computer 1990-04.pdf
Your Computer 1990-05.pdf
Your Computer 1990-06.pdf
Your Computer 1990-07.pdf
Your Computer 1990-08.pdf
Your Computer 1990-09.pdf
Your Computer 1990-10.pdf
Your Computer 1990-11.pdf
Your Computer 1990-12.pdf
Your Computer 1991-01.pdf
Your Computer 1991-02.pdf
Your Computer 1991-03.pdf
Your Computer 1991-04.pdf
Your Computer 1991-05.pdf
Your Computer 1991-06.pdf
Your Computer 1991-07.pdf
Your Computer 1991-08.pdf
Your Computer 1991-09.pdf
Your Computer 1991-10.pdf
Your Computer 1991-11.pdf
Your Computer 1991-12.pdf
Your Computer 1992-01.pdf
Your Computer 1992-02.pdf
Your Computer 1992-03.pdf
Your Computer 1992-04.pdf
Your Computer 1992-05.pdf
Your Computer 1992-06.pdf
Your Computer 1992-07.pdf
Your Computer 1992-08.pdf
Your Computer 1992-09.pdf
Your Computer 1992-10.pdf
Your Computer 1992-11.pdf
Your Computer 1992-12.pdf
Your Computer 1993-01.pdf
Your Computer 1993-02.pdf
Your Computer 1993-06.pdf
Your Computer 1993-07.pdf
Your Computer 1994-03.pdf
Your Computer 1994-05.pdf
Your Computer 1994-07.pdf
Your Computer 1994-09.pdf
Your Computer 1994-10.pdf
Your Computer 1994-11.pdf
Your Computer 1995-01.pdf
Your Computer 1995-02.pdf
Your Computer 1995-03.pdf
Your Computer 1995-04.pdf
Your Computer 1995-05.pdf
Your Computer 5 Year Index.pdf
Your Computer Data 86 The Sydney Business Computer Show.pdf
Your computer 1986-05.pdf
Jeremy@MBP Your Computer % 

So what’s new?

Hi everyone. Posting essentially to say I’ve been dedicated in scanning books, magazines and anything related to Australian vintage computing. As I’ve hit a personal milestone of over 100,000 unique PDF pages scanned now, I’d like to remind people of the link to browse and find something cool to read. In recent days I’ve added another large batch of files mentioned below.

All my content is shared publicly via paid Google Drive hosting which allows for direct download of either files or whole folders at high speed / no bullshit. Generally I don’t post to Archive.org as their batch uploader does not suit my needs at all. Plus I prefer having folders there to browse through like a BBS.

Recent efforts include scanning 35mm scans from DEC Digital archives (over 1000) and along with the images are the speeches that match – e.g Maxwell Burnet talk on the history of Australian computing has the slides and PDF speech. Please note the ton of DEC stuff I’ve archived has been stored by the ACMS and loaned out to me in bits and pieces over the years. It’s important to the ACMS president and myself they get a shout out. Remember you can view by thumbnail

Another massive project (10,000 + pages) was APDA – Apple Programmers and Developers Association documentation. Binder after binder of early Macintosh programming resources as donated for scanning by Sue Patterson, daughter of Michael who has passed away. Mike worked with Apple as an early programmer and had a keen interest in multimedia e.g. QuickTime, touch screen kiosks for Parliament House etc. He also collected Apple Australia published brochures, phamplets and so on. All of which have been scanned. I do have quite a lot of CDs that go with the documentation but I am overwhelmed by how long it takes to make ISOs of CDs and scan the artwork/do the file names. They are in safe storage though.

Other than DEC and Apple, this week we have new, random additions (copy and paste these into the search bar or find them by opening folders!):

Semiconductor Wall Chart – The Electronic Mailbox Australia
GA General Automation marketing for IBM 1130 upgrades (with comic book artwork)
Philips Miniwatt Valves catalogue
SHARP PC-122 Pocket Computer brochure
Zenith Data Systems Personal Computer Systems brochure
dLetter The Newsletter for dBase II and III Users
The Quadra 950 Apple Australia Industrial strengthened Macintosh (advertisement)
New folder for ‘Microcon Magazine of the Australasian Microcomputer Users Society and The Sydney Progressive Amateur Radio Club’

New and ultra rare are the scans from my personal collection of ‘General Magic and Magic Cap company and press releases’. If you’re into computing history you would know of how fundamental General Magic was to the iPhone.

I would appreciate funds towards hosting costs and also to upgrade my scanner and sharpen guillotine. PayPal jeremybh1@gmail.com paypal.me/jeremybh1

Sony RM-854 / Everything I know including a new Android based replacement

Hi everyone. The SONY PVM-2950 features an onscreen display and service menu that require a remote control with certain buttons to operate. For example number 12 on the remote is used to save values changed in service mode, not a common button on general SONY TV remotes.
Included here is an Android replacement. Open the folder “RM-854 Remote codes and IR Plus layout” here: https://drive.google.com/drive/folders/0BweO6Y13Cmc4VlFKYkx2MWxWU1k?resourcekey=0-ZImjHQr1ZkyLMpwZoW68XA&usp=sharing

There you’ll find the Android APK for IR Plus (free version) and an export of my codes and layout. Simply copy the file ‘SONY – PVM-2950 RM-854 Jeremy.irplus’ to the app’s Android Data folder, open the app, press import then SD. Immediately you’ll have my remote available which includes a special button called Service – a macro that sequences the service pattern with 500ms delay between signals. Tested working (remember monitor needs to be in standby).

IR Plus is free and compiled for devices on Android 4 and above which makes it ideal for use with old Samsung Galaxy devices with built in IR blasters.
The final result of my layout is shown below, again all you need to do is import my file to have this pop up:

I hope this helps anyone stuck for a Sony TV remote looking for either a direct replacement for their missing RM-854 like me.

Magnetic Media – Everything you wanted to know

The invention of recording sound, video and data on magnetic media has allowed for all kinds of information to be saved. The world has largely moved on to flash/NAND based storage which allow for a flexibility on formats – the main limitation is not what type of data it can hold but the capacity.

Over 100 years worth of ‘magnetic media’ has brought thousands of proprietary storage formats which has left a legacy of incompatibility and urgency in digitising what is left.

The IEEE Press have a book on the standards and how the technology evolved from war-time data storage, Bing Crosby Enterprises developing better audio recording standards, right through to high definition TV broadcasts which were state of the art at time of publication (1999).

Open the Google Drive link pinned to the homepage and search “Magnetic Recording – The First 100 Years.pdf”. Highly recommended reading!

Contents include:


Acknowledgments xv Contributors xvii

Chapter 1 Introduction 1

C. Denis Mee and Eric D. Daniel

The Growth of Magnetic Recording 1 The Four Enduring Product Formats 2 ALookattheFuture 4


Chapter 2 The Magnetic Recording of Sound 6 Mark H. Clark

Oberlin Smith’s Idea 7

Making Magnetic Recording Work 10 Biasing Techniques 11

Media and Head Design 11 Applications 13

Impact 13

References 14

Chapter 3 The Telegraphone 15 Mark H. Clark and Henry Nielsen

Inventing the Telegraphone 15




Research, Development, and the German Partnerships The Paris Exhibition 18

ConflictinGermany 21

A New Danish Strategy 22

Negotiations with American Investors 23 The American Telegraphone Company 24 Conclusion 28

References 29

Chapter 4 Steel Tape and Wire Recorders 30 Mark H. Clark

Germany 30

The United Kingdom 33 The United States 37

BellTelephoneLaboratories 38

The Brush Development Company 39 The Armour Research Foundation 41

Sweden 43 Japan 44 References 45

Chapter 5 The Introduction of the Magnetophon Friedrich K. Engel

TheBirthofCoatedMagneticTape 47 FritzPfleumer’sInvention 47

The Entry of AEG 49


Joint Development of the Magnetophon Recorder and Tape 50 BASFJoinstheTeam 50

TheFirstExperimentalTapeRecorder 50 EduardSchiiller’sInventionoftheRingHead 51

The Development of Coated Tape 52

Improved Laboratory Recorders 53

The Name Magnetophon Is Chosen 54 TheFourthLabModel 55 TheFirstProductionTapeRecorder:MagnetophonK1 56

The Debut of the Magnetophon Tape Recorder 56 TheMagnetophonGoesintoProduction 58

Magnetite Replaces Carbonyl Iron 58

From Magnetophon K1 to Magnetophon K4 60 The Magnetophon Pays a Brief Visit to America 60 APromisingNewOxide:GammaFerricOxide 60

The Main Users of the Magnetophon 61

The Magnetophon’s Recording Performance 62 The Big Leap in Quality: AC Bias Recording 63 Wartime Developments 65

A New Tape Base Material: PVC 65

AEG and BASF Launch Magnetophon GmbH 66


 Contents ix

Postwar Developments 67

The Birth of the Consumer Market 70 Sources 70

Chapter 6 Building on the Magnetophon 72 Beverley R. Gooch

CoatedTapeDevelopmentintheUnitedStates 73 Early Experiments 73

Tape Improvements 74

Consumer Recorders 76

The Brush Mail-A-Voice 76

The Brush Soundmirror 77 TheExpandingConsumerMarket 79

Semiprofessional Recorders: The Magnecorders 80 Ampex Professional Recorders 83

The Origins of Ampex 83 TheDevelopmentoftheModel200 84 TheIntroductionoftheModel200 87

Other Professional Recorders 89 Conclusion 90

References 90

Chapter 7 Product Diversification 92 Mark H. Clark

Professional Audio Recording 93 High-QualityRecordersforBroadcastUse 93 MasterRecordersforStudioUse 93 MultitrackRecordersforPopularMusic 94

Consumer Audio Recording 96

Open-Reel Recorders 96

The8-TrackCartridge 98

Early Tape Cassettes 101

Introduction of the Philips Compact Cassette 102 Licensing Tactics 103

Cassette Tape Improvements 104 Electronic Noise Reduction 105 DuplicationofPrerecordedCassettes 106 Other Cassette Applications 107

Conclusions 108 References 109

Chapter 8 The History of Digital Audio 110 John R. Watkinson

Principles of Digital Audio 110 Advantages of Digital Audio 114 Digital Audio Recording Principles 115

 Practical Digital Recorders 118

Digital Audio Based on a Hard Disk 119 Stationary-Head Digital Audio Recording 119 Rotary-Head Digital Audio Recording 120 Conclusions 122

References 122


Chapter 9 The Challenge of Recording Video 124 Frederick M. Remley

The Nature of Video Signals 125 AddingColortoTelevision 126

Recording Video Signals on Film 127

Magnetic Video Recording: Early Experiments 129

The First Broadcast-Quality Magnetic Video Recorder 130 Video Recorders for Home Use 131

Operational Factors Affecting Video Recorder Design 131 Television Production Requirements for Recording Systems 132

Television Production Processes 132

Program Exchange and Recording Standards 133 Summary 135

References 136

Chapter 10 Early Fixed-Head Video Recorders 137 Finn Jorgensen

The Main Players 137

Approaches to Recording a Black-and-White Video Improved Recorders Appear in 1954, with Color 144 Technology Advances, 1947-1956 145

BetterTapeHandling 146

True Phase Equalization atHigh Frequencies 147 Improved Heads 148

From the Mid-1950s to Now 148 Acknowledgments 151 References 152

Chapter 11 The Ampex Quadruplex Recorders 153 John C. Mallinson

Early Rotary-Head Video Recorder Attempts 154 The First Quadruplex Recorder (VRX-1000) 155 Subsequent Developments 160 —

The VR-1000 160

The VR-2000 162

Related Developments 165

The Videofile 165

The Tera-Bit Memory 166

Signal 141




The Digital Cassette Recording System (DCRS) The Demise of Quadruplex Video Recorders Conclusions 168

Acknowledgments 168

References 169

vd 167!

Chapter 12 Helical-Scan Recorders for Broadcasting 170 Hiroshi Sugaya

Video Recorders for Educational and Institutional Use 170 The Beginning of Competition for the Ampex Quad Recorder The First Helical-Scan Recorder to Replace the Quad Recorder A Broadcast Video Recorder for Electronic News Gathering

173 175


Competition in the Broadcast Video Recorder Industry A New Concept: Automatic Cassette Recorders 180 TheDigitalVideoEra 181

References 181

Chapter 13 Consumer Video Recorders 182 Hiroshi Sugaya


The Challenge of Fixed-Head Consumer Video Recorders TheDevelopmentofHelicallyScannedHomeVideoRecorders 183 Cassette (Two Reels) or Cartridge (One Reel)? 186

Betamax (Beta) Versus VHS in Japan 189 BetaVersusVHSintheUnitedStates 191

Beta Versus VHS in Europe 192

The First 8mm Video Format Conference 193

The VHS Compact Cassette (VHS-C) 195

The Development of Video Tape 196

Home Digital Video Cassette Recorders 197

Tape Duplication 199

References 200

Chapter 14 Digital Video Recording 201 Koichi Sadashige

DigitalRecordingofAnalogSignals 201 TheFirstProposalforDigitizationofanAnalogSignal 201 Attempts to Digitize Sound Recording 202 DigitalConversionofaVideoSignal 203 DigitalIslandsintheAnalogSea 204

High-Density Recording Technology 205

Instrumentation Recording 205 RunningonaMile-LongBridgeThatIsOnly2FeetWide 205

The Road to D-1 206

Initial Experimentation on Digital Video Recording 206 DigitalVideoRecorderStandardizationActivities 208 The First Digital Video Recorder 209

CompositeVideoDigitalRecording 210




TheNeedforaCompositeVideoDigitalRecorder 210

TheQuestforaSingleRecordingFormatforAllBroadcastApplications 211 Data Compression 211 ,

EmergingNeedsforDataCompression 211

Data Compression in Broadcast and Teleproduction Recorders 212 HDTV Digital Recording 213

DigitalRecordingofaHigh-DefinitionTelevisionSignal 213

Compressed Data Recording of an HDTV Signal 214 DV, Digital Video 214

DV, Universal Digital Recording Format for Consumers and Professionals 214

Broadcast-QualityVHSDerivativewithDV-BasedDataCompression 215 D-VHS, The Latest Member of the VHS Family 216

Disk Recorders for Digital Video Applications 216 LookingintotheFuture 218

References 219 DATA RECORDING

Chapter 15 Capturing Data Magnetically 221 James E. Monson

StoringData 221

Computer Applications 221 OtherApplications 222

Data Storage Requirements 223 Short-Term Versus Long-Term Memory 223 TransferRate,Speed,andAccessTime 223 Storage Density 224

Reliability 225

OperatingEnvironments 225

Cost 225

Removability and Portability 226 Archivability 226

Early Computer Storage Systems 227

The Memory Hierarchy 228 TheDigitalMagneticRecordingProcess 230

StorageofBitsofInformationonMagneticMedia 230 Writing 230

Reading 231

Head—Medium Interface 231

Tracking and Accessing Data Mechanically 232

Storing and Retrieving Data from Magnetic Memory 233 Conclusion 235

References 236

Chapter 16 Data Storage on Drums 237 Sidney M. Rubens

The Development of Magnetic Drum Technology 237



Recording Media 239

Magnetic Drums at Harvard University 246 The University of Manchester Computer 246 Magnetic Drum Developments atIBM 247 DrumsforPeripheralStorage 248 References 251

Chapter 17 Data Storage onTape 252 William B. Phillips

FiveDecadesofHalf-InchTapeStorage 253

The Uniservo I: The First Digital Tape Recorder 254 IBM Enters the Computer Market 255

The IBM 726 Tape Drive 256

Improvements in Half-Inch Tape Systems 260

IBM Tape Drives Using 10.5-Inch Reels 260 NewFormFactorsforDataTapeStorage 261 TheIBM3480TapeCartridgeFamily 261 Consumer Recorder Applications 263

Low-Cost Solutions 265 TapeLibrariesandAutomation 266

Other Impacts on Tape Storage System Design 268 Summary 269

References 269

Chapter 18 Data Storage on Hard Magnetic Disks 270 Louis D. Stevens

The Development of RAMAC 271 ProcessingDataFilesStoredonMagneticTape 272 Starting aNew Laboratory 273 TheSourceRecordingProjectandtheChoiceofDisks 274 A Broader View of Disk Storage 275 TheDiskProjectGetsMovingonSomeHardware 276 Designing the 350 RAMAC Disk Drive 278

A Decision to Build Machines for Field Testing 280 RAMAC IsHeaded forAnnouncement 280

TheEvolutionofMagneticDiskStorage 281 Self-Acting Hydrodynamic Sliders 281

The Removable Disk Pack 284 Track-Following Servo 286

Low-Mass, Lightly Loaded Sliders 287

Return to Fixed Disks 289

Thin-Film Heads 290

Smaller Diameter Disks 292

Magnetoresistive Read Heads, Thin-Film Disks, and PRML Channels

Summary 298 References 298

 Xiv Contents

Chapter 19 Data Storage on Floppy Disks 300 David L. Noble

Computer Operations 301 Fundamental Concepts 302 The Write Requirement 305 The Personal Computer 309 High-Capacity Designs 313 References 314

Chapter 20 Instrumentation Recording on Magnetic Tape 316 Finn Jorgensen

Early Data Recording Using Modified Audio Recorders (1935-1950) 316 The First Multichannel Instrumentation Recorders (1950-1980s) 317 Technology Refinements to Instrumentation Recorders Used in Space Telemetry (1960-1990) 322

SignalLinearity 323

Amplitude Variations 323 WidebandSignalSpectrum 323 Signal-to-Noise Ratio 324 PhaseVersusFrequencyResponse 325 PrecisionTapeTransport 326 TimingErrorsBetweenTracks 327

High-Density Digital Recording (1970-Current) 327 Digital Video Tape Recorders in Instrumentation 328 An Era Fades Away 330

Acknowledgment 331

References 331

Index 333

About the Editors 341

OCR and competitors

A short post to highlight the deficits that remain in Adobe Acrobat OCR version 22 DC. Compare the results with the open source Tesseract 4 which speaks for itself:

RetroChallenge 2021 Summary Jeremy Barr-Hyde

The aim of this blog post it to highlight the availability of over 400 images that have been scanned from the DEC Computer archives and Apple Computer, Inc. posters from the mid 1990s.

DEC Computer museum content – rising from the ashes but not quite a Phoenix

Source: My understanding is the DEC Museum of Australia held these slides and were maintained by Max Burnett Part of the challenge was ensuring slides were scanned and put back in the original order, and hand-written notes kept.

Most people will be viewing these online (opposed to TIFF files) so I’ve come up with a non-destructive watermark solution that captions each photo with the file name. This applies to the online gallery photos only – the originals are not watermarked and will be made freely available soon. If Max left a note like “CSIRAC Launch Group” then that will be displayed on the lower border.

The workflow is easier as I have decided upon a file naming convention and border/watermark process. However approximately 200 more 35mm slides remain to be scanned. Interestingly they are of DEC Computer employees and not just hardware photos. I believe when finished, this archive will be an unique resource for nostaliga over the legacy of hardware and the team that built it. So often we see photos and collections of hardware and not the effort behind them.

The initial gallery is publicly available via the official ACMS Facebook group/photo gallery: https://www.facebook.com/groups/AusVintage

Note: A great deal of consideration has gone into the physical scanning of these slides but dust and debris remain. This is due in part to some being interpositives. Meaning they are not directly from a camera, but duplicates from a master set.

Alongside the scans of 35mm slides was all the printed materials found in the folders, for example Maxwell Burnett’s slide notes that accompanied one of his many DEC presentations. I will be looking for volunteers to rename the PDFs when made available.

Apple Computer, Inc – Mid 1990s Posters now available for high resolution download or PDF

Michael Patterson of Canberra, Australia, kept a wonderful range of Apple developer resources from his time working as a programmer and university IT manager. I was fortunate enough to pickup hardware, software and printed materials from his estate and have been working in my hobby time to digitse what I can. A recent A3 scanner purchase has enabled me to tackle these huge foldout brochures and posters. I believe they are presented online for the first time and are freely available for direct, high speed download via the Google Drive link. Search for folder Apple Brochures; Posters; Stickers and employee business cards.

The RetroChallenge was motiviation for me to do the post processing work (e.g stitching, descreening) and ‘get them done’. 1200dpi TIFF files and 8 parts to stitch together isn’t always fun but we go there and the results speak for themselves. New for this month include and single page examples:

  • Apple – How you can use Macintosh color separation process poster (foldout 8×8 A4)
  • Apple Color Design poster 1994 – A2 double sided
  • The Human Mind – Apple HyperCard Freedom to Associate (2×2 A3 promotional booklet)

I hope someone will engage with the links or content and find happiness in these relics being brought to life.

Archive of Apple Developer Technical Publications

I’ve finalised the tasks of archiving a large lot of ADPA developer documentation from the 1990s as originally owned by Mike Patterson. He ‘kept everything’ including the original envelopes these papers were posted in, along with prices for membership renewal, which are also scanned. Each tome/file represents one binder of A4 papers and are available as 1200pi OCR’d PDF files via my public Google Drive. The contents serve as a time capsule of Apple Developer relations and written resources which show the power of the Macintosh classic platform.

Following the main link pinned on the blog, they are in the folder Scanned Book and Magazine Collection -> ADPA developer documentation and Apple Service binders.

This is also the first release of a ultra high quality scan of Apple Service Tech Procedures Macintosh Family Volume 2 072-0228. The existing version nternet archive is a start …. But we have Mike’s copy archived now so you may enjoy that in higher quality / searchable text etc.

3 different scanners were used in the making of this archive project (Epson Perfection V700, Fujitsu ScanSnap, Microtek A3).
Homebrew ocrmypdf was used for lossless compression of the text-only pages and Tesseract 4.0 for OCR.

Highly recommended one downloads these and scrolls through if you are interested in the inner workings of Macintosh in the very early 1990s.

None of this would be possible without Sue Patterson and her efforts in ensuring these materials were kept and donated to me in her father’s legacy. Thank you.

Examples of the peak 90’s covers (from inside the binders):

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