Floppy Disk Research Articles

FINITE ELEMENT ANALYSIS OF FLEXURAL VIBRATIONS IN HARD DISK DRIVE SPINDLE SYSTEMS

This paper is concerned with the flexural vibration analysis of the hard disk drive (HDD) spindle system by means of the finite element method. In contrast to previous research, every system component is here analytically modelled taking into account its structural flexibility and also the centrifugal effect particularly on the disk. To prove the effectiveness and accuracy of the formulated models, commercial HDD systems with two and three identical disks are selected as examples. Then their major natural modes are computed with only a small number of element meshes as the shaft rotational speed is varied, and subsequently compared with the existing numerical results obtained using other methods and newly acquired experimental ones. Based on such a series of studies, the proposed method can be concluded as a very promising tool for the design of HDDs and various other high-performance computer disk drives such as floppy disk drives, CD ROM drives, and their variations having spindle mechanisms similar to those of HDDs.

Friction characteristics of floppy disks

This note presents the principle and structure of a tribological measure for floppy disks. The precision of the force measuring system is 1 mN in loading and 3×10−6 N in friction. The resolution of the film thickness between head and floppy disk is 0.5 nm in the vertical and 1.5 nm in the horizontal direction. In order to investigate the tribological characteristics of floppy disks, six types of floppy disks have been tested and the floating properties of these disks are also studied with film measuring system. The experimental results of the surface morphology and friction coefficient of these floppy disks using the atomic force microscope/friction force mcroscope (AFM/FFM) are in accordance with the conclusion made by our own measuring system. The experimental results show that the air film thickness between head and disk is of the same order as the surface roughness of floppy disks.

Development of Integrated Optical Unit for Large Storage Capacity Floppy Disk

A small integrated optical unit suitable for a large storage capacity floppy disk drive is proposed. The optical unit is 6.8 mm wide, 3.3 mm deep, and 3.0 mm high. The distance between the laser diode and the focused beam on the disk is only 4.0 mm. The optical unit consists of two components, a lens unit and a laser-detector unit. In this optical unit, with the beam slanting incident on the disk, the reflected beam takes another path. Thus, a diffraction grating, a lens, and a deflector can be integrated into one component. The optical unit allows wide disk tilting of up to 2.4 degrees.

Reflex Magnetics Ltd: MailSafe

London-based Reflex Magnetics was founded in 1985. It started life as a disk copying company — but soon became concerned at the increasing danger posed by computer viruses. Reflex started to look for a way to protect its customers. It was concerned that it might receive a master disk from a client that was already infected with a virus, and that the virus might find its way onto the thousands of disks being copied for its customers. But there was nothing on the market that could provide the protection that Reflex sought. So Reflex developed its own solution: Disknet. Disknet puts a protective ring around a network; providing floppy disk authorization and restriction, matrix virus scanning, heuristic virus detection, boot protection and more. The result was an effective and efficient security product that rapidly gained both government and commercial customers, including all three of the armed services in the UK, the French and Italian navies, the European Union and many of the world’s top banks. Disknet was followed by Macro Interceptor, which automatically traps MS Office macro viruses, and Data Vault, a hard disk encryptor for desktop and laptop PCs that has gained CESG approval. With this amount of experience in encryption and security, it was only natural that the company should proceed towards securing E-mail.

The Development of a Novel Optical Floppy Disk Drive Using a Phase Change Optical Medium and a Quasi-Near-Field Optical Head

The optical memory system still has some shortcomings such as slow tracking access speed and high fabrication cost due to its relatively heavy head weight and complex optical elements. To overcome these limitations, a new lensless optical floppy disk drive has been developed using a phase change optical floppy disk and an external cavity semiconductor laser with a good antireflection (AR) coating on the emitting facet. The main components of this novel system are a contact-type head of quasi-near-field optics and a phase change medium prepared on a flexible polyimide substrate. The AR-coated semiconductor laser oscillates externally with the disk and its laser emission output shows sufficient variance to detect the phase difference on the recording layer. In our primitive drive, the simple optical head shows good writing performance and the recorded marks present sub-micrometer size, which indicate the high possibility of the development of a new, inexpensive floppy system of above 500 MB data capacity.

Transcatheter atrial septal defect occlusion in piglets by balloon detachable devices.

Detachable balloon devices were applied in the occlusion of experimental ASDs in 20 piglets. The detachable balloons were made from Latex; the occluder balloon was placed on the left atrial side and required a floppy disk and counter-occluder(s) support from the right atrial side (17 experiments), or a second detachable balloon from the right side (3 experiments). Full occlusion was noticed in all cases. There was one device embolization in the descending aorta (device with a regular floppy disk and no counter-occluder). The device was covered by tissue in 3 to 4 weeks with the balloon flat on the septum in approximately 2 months; it required minimal rim and no wires in the left atrium. The double balloon model was wireless. The balloon detachable device was found effective and safe in the occlusion of experimental ASDs in piglets.

Possibility of 3 Gbits/in/sup 2/ floppy disk

We tried to realize Gbits/in/sup 2/ class Floppy Disk with a magnetic layer prepared by sputtering (SP-FD). The heat-durable undercoat and the underlayers made magnetic layer have Gbits/in/sup 2/ properties, with higher S/N and narrower PW50 In comparison with those of 3.1 Gbits/in/sup 2/ HD. Heat durable substrate, fine protrusions and aerodynamics consideration allowed to achieve stable and nonaggressive contacts and good durability after running for more than 250 hours at three different environment conditions. We can conclude that the SP-FD has the potential of 3 Gbits/in/sup 2/ FD.

Electronic karyotype transmission

The Internet offers a wealth of resources for clinical geneticists. Literally millions of sources of specialized information, search engines, listserves, patient support resources, and online conferencing are available and enhance knowledge, efficiency, and patient care. For the clinical cytogeneticist, internet transmission of high resolution karyotypes and FISH images provides another valuable electronic tool. Pictures can be downloaded from an imaging system onto a floppy disk and e-mailed after removal of patient identifiers. They can be viewed with a simple graphics program and the results quickly reported via return email or telephone. This remote case review by the laboratory director or a designee solves the majority of laboratory coverage problems and maintains turnaround time and efficiency. In addition it provides immediate karyotypes or FISH images when consultation is needed. Emailing of images allows sharing of data among colleaques regardless of differences in computerized image will require microscope the few drawback

A novel magnetic contact duplication technique for servo-writing on magnetic disks

A novel magnetic contact duplication technique is proposed in order to write a servo signal on hard disks and floppy disks at a high speed and a low cost. In this technique a magnetic layer of a master disk is lithographically patterned in accordance with a servo signal, having low coercivity, and dc magnetic field is applied to a slave disk contacted with the master one. A computer simulation using finite element method shows that the pattern of the master disk can be duplicated on a slave. The possibility of duplication by using this technique is confirmed from experimental results in which a Bitter pattern of a duplicated slave medium is clearly observed.

If not now, when?

If not now, when?

Readback properties of novel magnetic contact duplication of high recording density floppy disk

We observed the readback signal from a floppy disk (FD) media prepared by a novel magnetic contact duplicated method. The signal amplitude, PW50, and CNR were nearly same as that using the traditional method. It was confirmed that this technique has a high potential to write servo signals in high Hc media.

Sony's Yoshihide Nakamura on structure and decision making

In May 1946, Masaru Ibuka and Akio Morita founded Tokyo Telecommunications Engineering Company. The name was changed to Sony Corporation in 1958, a name derived from the Latin word sonus, or sound, and the English sonny, a young man. Sony developed the world's first transistor radio in 1955. It was followed by such revolutionary products as the Trinitron color TV (1968), Walkman (1979), compact disc player (1982), Betacam for broadcast use (1982), floppy disk (1983), Handycam (1985) and the Playstation (1994). Today, Sony is a leading manufacturer of audio, video, communications and information technology products for the consumer and professional markets. Its music, pictures, and computer entertainment operations make Sony one of the most comprehensive entertainment companies in the world. More than 100 million units of the Walkman have been sold in the U.S. alone. Sony employs 170,000 people worldwide. For the fiscal year ended March 31, 1999, sales and operating revenue were US $56.6 billion. Yoshihide...

Inexpensive, semi-automated system for measuring mechanical properties of soft tissues.

Stiffness and strength are important properties of many tissues, but standard material-testing equipment is expensive, often ill-suited for testing soft tissues, and rarely accessible to biologists. We describe a system built around a microcomputer and an electronic balance which is particularly well-suited for measuring stress and strain in small samples of soft tissue. We use a discarded floppy disk drive as a linear actuator to strain the sample, while an electronic balance measures the tension (used to calculate stress). We give an algorithm for a program to drive a microcomputer which controls the floppy disk drive via its parallel port and records the balance measurements via its serial port. We used this system to obtain stress-strain curves from a sample of latex rubber and a sample of soft insect cuticle. Three tests of the rubber sample gave nearly identical results, with smooth, J-shaped stress-strain curves. The stress-strain curves gave a modulus elasticity value of 1.72 Mpa over the steep, straight region, well within the range for natural latex rubber. We also tested a sample of abdominal cuticle from a caterpillar (Manduca sexta). The caterpillar cuticle had a J-shaped stress-strain curve with a modulus of elasticity of 2.11 Mpa over the steep part of the curve. J. Exp. Zool. 284:374-378, 1999.

More tables, less trees: five solutions for paperless distribution of research findings

Market research reports still continue to be expected to arrive in paper form despite the advances in electronic publication and dissemination of information. Users still expect to be able to locate a table, produce copies and type them into reports. Argues the potential of electronic publishing techniques for improving this process by outlining the inherent disadvantages of paper based distribution. Considers the available technology, including browsers and end user analysis tools. Accepts the value of the Internet but points to the continuing value of physical media such a CD-ROM and floppy disk. Reviews in detail five specific tools available, including: Adobe Acrobat; ITE electronic fiche; SPSS SmartViewer; Memphis Survey Explorer; and Pulsar. Reports practical experience gained with these technologies at the European Commission (ITE), UK’s Office for National Statistics (ITE); and Public Affairs Department, London Borough of Barnet (Survey Explorer). Concludes that, when replacing printed market research reports with something that relies an computer technology, it is vital that users of the data perceive the new solution to be more useful and as easy to use.

Millennium bug ‐ are you solving the right problem?

Asserts that the “millennium bug” debate generated by UK Government activity, PR and media activity is at last gathering momentum. Enlightened business people are already well down the track of preparing their companies for potential problems. However, the more sceptical, ill‐informed or ostrich‐headed are still looking for an easy way out, if they are looking at all. They are being selective in the message they choose to hear and minimalist in the solutions they adopt. This is building a significant problem. One of the results of these circumstances is that advertisements that promise a “total confidence” solution through the purchase and use of a simple floppy disk are grasped and believed in a literal sense. In reality these “solutions” while valuable, are at best only partial. At worst, relying on this alone could put an organisation into a terminal risk situation. Suggests an “enterprise‐wide” or “business process” solution ‐ based on the risk exposure unique to the individual business.

Virtual courseware for geoscience education: Virtual Earthquake and Virtual Dating

Virtual courseware developed for introductory-level, on-line geology labs is an interactive teaching/learning model that has an enormous pedagogical potential for making Web sites places where students learn by doing. Virtual Earthquake and Virtual Dating are modest examples of the `virtual courseware' paradigm. Virtual Earthquake helps students explore the techniques of how an earthquake's epicenter is located and how its Richter magnitude is determined. Virtual Dating models the theory and techniques of the radiometric age determination of rocks and minerals. Virtual courseware applications offer several advantages over traditional floppy disk or CD ROM-based courseware, the most significant being the ease of dissemination. The author's experience with bringing these two virtual applications on-line suggests that there is a need for interactive geology labs on-line and that the approach will be received with enthusiasm by the educational community. The widespread implementation and adoption of virtual courseware can bring meaningful educational content and interactivity for the geosciences that goes beyond multimedia on the World-Wide-Web.

Confessions of a “Techno-Teacher”

Long, long ago, when there were 51/4-inch floppy disks, 8086 processors, and monochrome monitors, my psychology students sat in front of computer screens monitoring how often amber-colored cartoon com puter pigeons would peck at a disk in a virtual Skinner box. Today, in the era of CD-ROMs, Pentium chips, and multime dia, the course-related software is much more sophisticated, informative, and dare I say it, entertaining, as it incorpo rates hypertext, video, animations, and sound into modules that students can explore independently in a multimedia computer lab on campus or on their home computers. Students now submit word-processed reports on their discov eries and correspond with one another and with me via e-mail.

A nostalgic demonstration of the radian

Although it may be safe to put away your spotted yellow power tie and floppy computer disks that are actually floppy, the current generation of students excitedly associate this demonstration of the radian with an icon of the 1980s that is still going strong: Pac-Man™.

Product review: lucis image processing software.

Lucis is a software program that allows the manipulation of images through the process of selective contrast pattern emphasis. Using an image-processing algorithm called Differential Hysteresis Processing (DHP), Lucis extracts and highlights patterns based on variations in image intensity (luminance). The result is that details can be seen that would otherwise be hidden in deep shadow or excessive brightness. The software is contained on a single floppy disk, is easy to install on a PC, simple to use, and runs on Windows 95, Windows 98, and Windows NT operating systems. The cost is $8,500 for a license, but is estimated to save a great deal of money in photographic materials, time, and labor that would have otherwise been spent in the darkroom. Superb images are easily obtained from unstained (no lead or uranium) sections, and stored image files sent to laser printers are of publication quality. The software can be used not only for all types of microscopy, including color fluorescence light microscopy, biological and materials science electron microscopy (TEM and SEM), but will be beneficial in medicine, such as X-ray films (pending approval by the FDA), and in the arts.

Development of high capacity floppy disk “HiFD”

We report development of high capacity floppy disk “HiFD”, by applying advanced metal particles with high performance to flexible disk. A 200 megabyte storage capacity is realized on 3.5 in floppy disk. In case of high capacity floppy disk the surface design of the disk is very important not only for recording characteristics but also durability and head flyability, because the contact condition of high capacity head differs from that of current MFD heads. To improve the durability of HiFD disk, the surface design was investigated in terms of size of abrasive particles. Flat surface with adequate height of spikes that were made of alumina fine particles is an important factor for durability. Flat surface may produce a stable air film on the disk, which makes less contact frequency and assures a long life time.