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Green Image
Issue No. 05 - May (2006 vol. 39)
ISSN: 0018-9162
pp: 11-12
May 1974
THE WILLIAMS TUBE (p. 12). "The Williams tube memory device, an important pioneering invention in computer technology in the late 1940's, was presented to the Smithsonian Institution on Wednesday, April 10 by Mr. David Pacey, Vice President of Ferranti Electric Inc., on behalf of the Ferranti organization of Manchester, England."
"The device, which uses a CRT and stores information as a binary coded pattern of electric charges on the tube face, led to computers capable of high speeds compared with other machines of the period which used acoustic delay lines.
"The actual unit presented to the Smithsonian was installed as part of a Ferranti Mark I computer system delivered in 1954 to the A.V. Roe Company, of the Hawker Siddeley Group. For the next ten years this particular system solved problems associated with aircraft design, management studies, and machine tool programming."
IMAGE COMPRESSION (p. 22). "With the increasing emphasis on the use of digital communication systems, digital image compression techniques are drawing considerable interest as possible means for reducing the capacity requirements of the digital communication channels. An encoding scheme widely used for the transmission of digital signals is pulse code modulation (PCM), which has been refined considerably since its invention in 1939. Such encoding generally involves the sampling of the analog input signal at a uniform rate and encoding the samples in a binary code. This provides an adequate number of quantizing levels, in order to maintain a required signal-to-noise ratio. Such techniques have been applied to voice, images and other signal waveforms such as telemetry and biomedical data.
"Conventional PCM techniques require a high data rate (or equivalently large bandwidth) for the transmission of images. Therefore, many new digital schemes have been explored in order to reduce the capacity requirements of the digital image communication systems, by making use of the statistical and psychovisual redundancies in images."
LASER BEAM RECORDING (p. 88). "The first computer-output-microfilm system using a laser to record high-quality alphanumeric symbols on 105mm microfiche or 16mm roll microfilm has been introduced by the 3M Company.
"The Laser Beam Recorder (LBR) can be used with or without a forms overlay. It writes directly on Dry-Silver microfilm, forming a latent image that is developed by heat, requiring no liquid chemicals. The beam originates in a helium-neon laser that produces only six milliwatts and operates at room temperature. An acousto-optic modulator breaks the beam into zero-to-seven deflected beams to write on a grid 7 positions high by 5 positions wide."
MAGNETIC CARDS (p. 91). "A magnetic card transport device that reads and writes IBM-compatible cards has been introduced by Redactron Corporation.
"The new model, 270/280, is a 50-track magnetic card transport with a 5000 character memory. It achieves access to a block of material in approximately 1.8 seconds.
"Advantages of the magnetic card over other recording media include: magnetic cards are easy to handle and store; each card can store up to 5000 8-bit characters; a single card can store material that would require 40 feet of paper tape or 50 punched cards; each card is a unit record. The cards also have individual protective jackets with space to note what information is stored on each of the 50 tracks on the card. Unlike paper tapes, magnetic cards can be used repeatedly, with a guarantee of 2000 passes per card in either the read or write mode."
YELLOW PAGE UPDATING (p. 93). "L. M. Berry, one of the nation's major suppliers of directories for telephone companies, has developed a computer-supported system that replaces manual revising and updating for yellow pages."
"On a daily basis, written and telephoned changes on new and existing national ads in approximately 5,000 directories are received at the L. M. Berry office.
"Under the old system, a NYPS order form was completed by hand, listing the exact way the advertising was to be printed; then it was transcribed onto a computer order form, forwarded to the data processing department for keypunching, converted into paper tape, and delivered to a publisher.
"Under the new system, an account representative enters changes or new insertions directly into L. M. Berry's computer, an IBM System/370 Model 145."
COMPUTER ANIMATION (p. 94). "Computer animation has made enormous strides during the past two or three years. Combining a hybrid analog-digital computer with television components, systems such as the one at Computer Image Corporation of Denver, Colorado can now produce character animation approaching the quality achieved through conventional animation methods. Perhaps even more significant, such systems can do in one day what a conventional animator working with standard equipment might take as much as two or three weeks to produce. That's why commercial filmmakers are following developments in computer graphics with growing attention."
May 1990
OPERATING SYSTEMS (p. 5). "Dramatic changes in operating systems have resulted from enhancements to the hardware technology, experience with existing systems, development of new applications and needs, and, of course, imagination. Ten years ago, networking was an interesting concept with a few, unique interconnected systems; today, it's become a requirement. The combined developments of Ethernet and commodity microprocessors have provided a new environment of high-performance, single-user graphical workstations. LANs filled with personal workstations have created the demand for efficient use of computing and storage resources. Wide area networks, with the potential for worldwide connectivity, provide the possibility of global access to computing resources. Unfortunately, global agreement over the protocols used to access these resources seems unlikely, thereby placing new demands on operating systems to provide users with uniform and integrated data access."
CENTRALIZED TIME-SHARING (p. 44). "In the next decade, computer prices will drop so low that 10, 20, or perhaps 100 powerful microprocessors per user will be feasible. All this computing power will have to be organized in a simple, efficient, and fault-tolerant system that is easy to use. The basic problem with current networks of PCs and workstations is that they are not transparent; that is, users are aware of the other machines. The user logs into one machine and uses that machine only, until doing a remote login to another machine. Few if any programs take advantage of multiple CPUs, even when all are idle.
"We envision a system for the 1990s that will appear to users as a single, 1970s centralized time-sharing system. … All resources will be managed completely and automatically by a distributed operating system."
STANDARDS WRITING (p. 81). "Careful writing is important to avoid unnecessary requirements that can be costly to implement or meet and have no intrinsic value for successful adherence to the standard. This area has received a great deal of attention over the past several years because studies have shown that counterproductive requirements can lead to unnecessary and excessive costs. One of the best arguments is: Why is only one specification document required for constructing a 747 jet airliner, but 14,000 such documents are needed to build the US President's new Air Force One, which is also a 747?"
LASER PRINTERS (p. 90). "With the street price of laser printers now challenging the price of high-end dot matrix or ink jet printers, the price-performance ratio and the quality of laser printers make the competition look really terrible.
"As we all know, if you want to squeeze every last drop of utility and performance out of your PC, you have to spend a lot more time at it than your loved ones would like. So it is with laser printers. It's just not as simple as switching the printer on-line and feeding in a bunch of paper. Now, you have to know about hard and soft fonts, pitch and point size, minute differences among hundreds of available fonts, and the possible effects of your choices."
QUERIES VIA FAX (p. 98). "Spectrafax offers an information retrieval and delivery system called Special Request. The system combines synthesized voice communication and facsimile transmission to respond to requests for information sent by customers via fax. It is based on the Spectrafax Personal Link and Voice Messaging products.
"Authorized callers can use the touchtone telephone on a standard Group III fax machine to request and retrieve copies of data from a database stored on a mainframe or PC, or accessed across local area networks. The system responds to calls using an electronic voice synthesizer. The caller can select one or more documents from the menu of available documents by pressing the appropriate number on the fax phone."
THE CUCKOO'S EGG (p. 106). "The all-too-usual reaction when a computer center detects an intruder, Cliff Stoll said at CompCon Spring 90, is to disable his access, close the security hole, and notify the users, but otherwise keep the happening close to the vest. This is the wrong reaction, Stoll told an invited-lecture audience. 'What we did at Lawrence Livermore National Laboratory was keep the hole open and let the guy in, but monitor everything he did.'
"Eventually, Stoll suspected the hacker was operating out of Germany. But the hacker's chain from his own computer to LLNL extended through half a dozen intermediate sites. It took time to trace all those telephone links backwards to the invader's home base, and he was cautious. He did not stay on the line long enough for tracing to be completed. Eventually, Stoll created a splendid, lengthy, but phony file he called SDInet. That lured the hacker into downloading it, and that took long enough to trace the call.
"The wily hacker turned out to be 26-year-old Marcus Hess of Hanover, West Germany. Just a week and a half before CompCon 90, the trial was concluded. The very clever—and cautious—invader received a two-year sentence."
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