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Magnetic tape storage has been used for recording audio, video, instrumentation, and computer data. The medium can record a large amount of data on winding tape and recorded data are reliable and stable. However, the performance of the other storage media, such as optical disc, magnetic disk, and integrated circuit memory, has progressed remarkably, so the advantage of tape storage has decreased. Video tape recorders (VTRs), which are typical systems for magnetic tape storages, are only used for limited purposes now. For these applications, data storage that records instrumentation and computer data on tape retains its advantages and its performance has been improved. We described the history of VTRs at the HISTELCON 2010 and showed that Japan made substantial contributions to their practical use and popularization. In this paper, we compare the vicissitude of magnetic tape data storage with video tape recording.

The study investigated, in a Nigerian setting, whether the use of videotape recordings is an effective method of teacher education prior to full-time teaching. Two groups of students were used for study. The first group was allowed to practice the skills through micro-teaching with the aid of video recording equipment. The second group practiced their own skills through micro-teaching but without the aid of video recording equipment. At the end of the study it was discovered that the group which used the video recording equipment had more significant progress in the mastery of teaching skills.

A new D-VHS system developed on the basis of the VHS video tape recording format has been developed for recording digital data compatible with digital broadcast systems. The system can handle a variety of digital formats to meet the diverse needs of multimedia applications.

At the dawn of video tape recording in the early 1950s, various recording systems were proposed by American, European and Japanese engineers. Among them, the transverse scanning system was the first practical system to be used. Twenty years later, helical scanning systems gained in popularity and many VTR (video tape recorder) formats began to appear in the broadcasting market. The helical scanning system progressed with the use of tape cassettes, which employed narrower tape, and with the adoption of high density recording technologies. At the end of the 1980s, more digital VTRs began to appear. New systems expanded the uses of VTRs with their many advantages. Over this period, Japan had the largest market share of VTRs in the world. The author reviews the history of broadcast VTRs and traces the organizations and individuals that contributed to the progress of VTRs. The factors that contributed to Japanese manufacturers being a dominant force in the production of practical VTRs are considered.

This chapter provides an overview of the development of video tape recording. The story of video tape recorders really began before the turn of the century with the experiments of Valdemar Poulson. By this time, the relationship between electricity and magnetism was well understood, and the idea of impressing magnetic pulses on a moving magnetic medium was sufficiently advanced in 1900 to justify a US patent on Poulson's apparatus, the telegraphone. The medium was magnetic wire rather than tape, was without any form of recording bias, and had scant means of signal amplification; also, the reproduced sound signal was low, noisy, nonlinear, and lacking in frequency response. These problems of tape and record or replay head performance are ones that have continually recurred throughout the history of sound and vision tape recording. The magnetic wire gave way to steel tape 6 mm wide travelling at 1.5 meters per second, and performance became comparable with the contemporary disc recording system.

We present a planar thin-film servo write head for writing timing-based servo patterns. The planar head operates at low current ( ~ 100 mA) with nanosecond switching times. The planar head can handle dc current, enabling trailing-edge writing. Magnetic force microscopy measurements of the transitions written by the planar head and a conventional commercial servo write head on longitudinal metal particle and nonoriented barium ferrite media were made to assess the quality of the written transitions. The transition response width PW50 is found to be independent of the tape velocity during write for the planar head. For the conventional head, PW50 is larger and increases with the tape write velocity. The reduced PW50 results in larger readback signal amplitude and hence an improved track-follow performance. The faster switching capability of the planar head enables formatting at higher tape velocity.

We examine the issue of scaling magnetic tape-recording to higher areal densities, focusing on the challenges of achieving 100 Gb/in2 in the linear tape format. The current highest achieved areal density demonstrations of 6.7 Gb/in2 in the linear tape and 23.0 Gb/in2 in the helical scan format provide a reference for this assessment. We argue that controlling the head-tape interaction is key to achieving high linear density, whereas track-following and reel-to-reel servomechanisms as well as transverse dimensional stability are key for achieving high track density. We envision that advancements in media, data-detection techniques, reel-to-reel control, and lateral motion control will enable much higher areal densities. An achievable goal is a linear density of 800 Kb/in and a track pitch of 0.2 µm, resulting in an areal density of 100 Gb/in2.

Magnetic tape systems provide high reliability storage at a low total cost of ownership and are well suited for the long term storage of less frequently accessed data. The current explosive growth rate of digital data is driving demand for cost effective storage technologies and has resulted in a renaissance in applications for tape systems. Current state of the art tape systems operate with areal densities up to ∼6 Gb/in2 and provide cartridge capacities up to 10TB. The future success of tape systems depends on continued areal density and capacity scaling to maintain or increase the current cost advantage of tape over competing technologies. In this work we describe a set of technologies that enable the scaling of tape recording to areal densities of 100 Gb/in2 and beyond.

In this study, the signal-to-noise ratio (SNR) performances of longitudinally, randomly, and perpendicularly oriented particles, based on hexagonal barium ferrite (h-BaFe) platelets with an average volume of 2400 nm 3 have been studied as a function of the recording head to media distance by numerical micromagnetic simulations. The distances from the write head to media and from the read head to media were varied independently. For a fixed read distance and varied writing distances, the SNR was decreasing in larger write distance. An optimum write distance of 40 and 50 nm was found for the longitudinally oriented media and the perpendicularly oriented media, respectively. The optimum write distance for longitudinally oriented media, 40 nm, resulted in the local minimum SNR for the perpendicularly oriented media. In most write distances the perpendicularly oriented media show the outstanding best performance, but near the write distance of 40 nm the longitudinally oriented media work as good as the perpendicularly oriented media. In a fixed write distance with various read distances, the SNR was almost constant in each media whereas the average signal amplitude was exponentially decayed in larger read head to media distance. The best SNR was found in the perpendicularly oriented media at write head to media distance d write =20 nm and read head to media distance d read =40 nm. The best SNR value is 11.9 and 24.4 dB in time domain and frequency domain, respectively.

Magnetic tape recording is one of the oldest data storage technologies, and it is still used today due to its low cost and long data storage life. Magnetic tape recording is a contact recording technology, where a thin flexible magnetic tape medium is pulled across an Al2O3/TiC (AlTiC) recording head surface at a high velocity while in direct physical contact with each other. As a result, one of the inherent problems faced in magnetic tape recording systems is an increase in the magnetic spacing over time with prolonged usage, due to continuous wear of the tape bearing head surface, which in turn leads to a deterioration of the magnetic readback signal [1]. The increase in the magnetic spacing at the head-tape interface can be due to several factors, such as pole tip recession (PTR), accumulation of wear debris on the head and surface roughness of the head and tape medium. Out of these factors, PTR is a major contributor to the magnetic spacing loss, due to a higher rate of wear of the softer magnetic read and write poles at the head-tape interface [2].Copyright © 2014 by ASME

The Pole Tip Recession (PTR) and transferred material (stain) are major causes of magnetic spacing losses in magnetic recording system. The recorded signal amplitude is only independent of the data being read if the spacing is zero. Thus, the level and more specifically the variation in head media spacing with device life must be a minimum to maximise signal output and minimised errors. It was the purpose of this research to isolate and identify the mechanisms responsible for pole tip recession using the Linear Tape Open format as an experimental platform, but the results have implications for any head where the tape-bearing surface is Al2O3/TiC (AlTiC). All experiments were conducted within a matrix of pressure and humidity, which encompassed the system operating extremes. Atomic force microscopy (AFM) was used to analyse the surface topography of the heads and monitor the development of PTR after 100, 1000 and 5000 passes of tape. Auger electron spectroscopy (AES) was employed to analyse the chemical changes on the surface of the heads after 5000 passes of tape and X-ray Photoelectron Spectroscopy (XPS) was used to identify the chemical changes that occurred at the head surfaces. Optical Microscopy was employed to identify the head surface changes before and after wear. Environment was found to have a significant influence on the head/tape interface. Head wear and PTR were highest at high temperature and humidity. Wear between the head and tape was found to transform the surface layers on the TiC grains in the tape-bearing surface to TiO2. This process results in the production of TiO2 fragments that become trapped in the recessed pole tip region, acting as three-body abrasive particles. The presence of Ti on the surface of head thin film region confirmed that the three-body particles originated from the head AlTiC ceramic. The TiO2 (thickness and possible areal coverage) increased with the water content increase, wear of head increased in the high water content condition.

In this paper, we report the properties of Co/Cr and CoCrPt/CoCrMn thin films grown by oblique sputtering onto polymer substrates. It is observed that in both cases, the underlayers promote the formation of HCP-structure of the magnetic layers, which results in a high magnetic anisotropy of the films consequently, high coercivities of 200 and 300 kA/m are obtained in the 20nm Co/180nm Cr and 30nm CoCrPt/50nm CoCrMn films, respectively. However, in the case of Co/Cr film, Co grains are relatively large and elongated following the transverse direction while in the case of CoCrPt/CoCrMn film, a tiny columnar structure inclined toward the incident direction is observed. This fact results in a different magnetic behavior of these films.

Digital tape recording systems show the same trend as hard-disk drives: a large increase of storage density with time. The use of advanced media and highly sensitive thin-film heads with magnetoresistive (MR) readout will increase the storage density dramatically. Key improvements are narrower tracks, more sensitive MR elements attained by applying the giant magnetoresistance effect, high-saturation flux density pole materials, advanced metal powder tape, intimate head-to-tape contact, and accurate tracking. By increasing the number of channels in the multitrack thin-film head, high data rates can be obtained as well. The basics of digital magnetic recording are discussed and a short historical overview is given of the Philips activities on thin-film heads for tape recording. An outlook on future improvements is given.

IBM thin-film tape heads have evolved from the ferrite-based heads first used in the IBM Model 3480 Tape Drive to the hard-disk-drive (HDD) technology flat-profile heads used in IBM Linear Tape-Open® (LTO®) products. This paper describes that transition and discusses the flat tape head manufacturing processes, drive implementation, performance, and outlook. Thin-film head technology for hard-disk drives was first used in tape heads in the early 1990s, when IBM built quarter-inch cartridge head images on HDD-type wafers. This was a springboard for the next step, flat-lapped tape heads, which use not only HDD wafers, but also HDD post-wafer machining technologies. With the emergence of LTO, flat heads entered mainstream tape head production in IBM. These have proven to have high performance and durability.

The mechanics and tribology of a flat head for high-speed, contact tape recording is presented. Experiments performed on a “row-bar” of thin-film disk heads where the tape is wrapped only on the edge opposite to the heads showed very stable contact for a wide range of tape speeds and very low wear. A model of the interface showed that a self-acting, subambient air bearing forms near the leading wrapped corner. This suction is caused by the expansion of air into the diverging gap on the upstream side of the head-tape interface, which is unique to this wrap geometry, and it is responsible for the stability and low contact pressures. A bidirectional version of a flat head geometry is analyzed via modeling and suggestions are made for that design. This work also showed strong evidence of a threshold of contact pressure below which wear becomes negligible.

The SSQ-1 Digital Tape Recording Horizontal Pendulum Tiltmeter is an instrument of high sensitivity to detect the changes of ground tilt. It uses a quartz horizontal pendulum held by Zollner bifilar suspension to sense vertical displacement, the eddy-current transducer on the pendulum converts its displacements into electric signals. Then a microcomputer is used for data acquisition and printing as well as digit tape recording. And at the same time, a filtering pen recorder is used for visible recording. The scale value of the instrument is calibrated by computer using the known tilt angle of the bulging plate — mercury cup. The scale value is 0.3–0.5 m(″)/mV.

A recently developed, advanced multi-track tape head for operation in a next generation, high performance tape drive is described. This head features full thin film write elements with high moment, cobalt-based pole materials for recording on high coercivity metal particle (MP) tape, together with narrow track, shielded, dual-stripe magnetoresistive (DSMR) read elements. This presentation will discuss the global design philosophy of the head with particular attention to the design and recording performance of the read and write elements in a tape environment. The bead is capable of recording 288 tracks on half-inch, MP tape of 1625-1850 Oe coercivity at a recording density of 65 kfci. The system operates with 16 parallel data channels and includes full multi-element active track following servo. The head can be used in a full start-stop mode and read verify on the fly (read-while-write) bi-directional operating modes.

In this paper we present results on the fabrication and testing of thin film tape recording heads using high moment FeAlN pole materials (4/spl pi/M/sub s/=20 kGauss). These heads are of the type used in quarter inch cartridge (QIC) tape drives, with a record gap dimension of 1.9 /spl mu/m and a written track-width of 33 /spl mu/m. The pole thicknesses ranged from 4 to 4.5 /spl mu/m with a 14 turn coil. The FeAlN pole material delivers sufficient field to the media surface to saturate 1.5 /spl mu/m thick Ba-Ferrite media (H/sub c/=1500 Oe). In comparisons to a head of identical design with CoZrTa poles, the FeAlN poles were able to deliver more flux to the media because of a higher head saturation onset current.

This paper reports on the concept and configurations of the desktop program production (DTPP) system and specifications of the storage system for the multimedia data base in the DTPP. The current technologies of VTRs, hard disks, and magneto-optical disks for the storage system, as well as the latest research results related to high-speed and high-density recording technologies, are also introduced.

A self-consistent micromagnetic recording model is utilized to study the effects of write head field rise time in tape recording. It is found that fast speed and slow field rise time result in degradation of recording performance for both nonequalized and write equalized cases. It also suggests that D=T/2 scheme could be more suitable than the D=T/3 scheme in write equalization at high speeds.

In this work, the performance of a narrow track MR head/MP tape recording system was evaluated focusing on the MR head saturation. Readback density of 0.65 Gbits/in/sup 2/ was attained with reasonable SNR of 18.2 dB using a 5 /spl mu/m trackwidth MR head and thin layer MP tape. Saturation at low densities was suppressed by the selection of a run length limited 8/10 modulation code. This result suggests that the excellent performance of the narrow track MR head could increase areal density in tape recording, and would steer the development of particulate tape media toward reduction of magnetization thickness product and improvement of media noise characteristics.

The system of disc recording used a groove cut in shellac (or later, vinyl) disc and modulated by the sound waves. For good-quality recording, the bass amplitude must be reduced and the treble frequencies boosted on recording and the opposite actions carried out on replay. Electrical recording and reproduction offer much more control over the process. Disc stereo recording uses a cutting head whose stylus can be vibrated in two directions that are at right angles to each other, cutting tracks in the walls of the groove. Tape and cassette recording of sound is not new, but the methods that are used to make the sound of acceptable quality are of recent origin. All magnetic recording makes use of a magnetic material being moved past a recording/replay head which consists of a metal core with a narrow gap and a coil of wire, and the construction of this head is very exacting if good-quality recording is required. Noise is the enemy of all recording and broadcasting systems. For professional recording, the use of wide tape overcomes the problem to a considerable extent because a wider tape has a larger magnetized area and so produces a larger signal that “swamps” the noise. Noise-reduction systems operate on the principle of selectively boosting the amplitude of the recorded sound when it is recorded and decreasing it on replay, and a particularly effective method of doing this concentrates the boosting and reducing actions on the frequency range that is the most affected.

The new generation of FELs should be more compact than present designs. One important way to achieve this size reduction is to use microwigglers. Measurements and mapping of the magnetic field inside electromagnetic microwigglers is at present a difficult task because of the small dimensions of the microwiggler, the requirement for high spatial resolution in the measurement of the magnetic field, and the need to obtain a fast response since the field-producing pulse may be of short duration. We present a new method for quick measurement and mapping of the microwiggler field. Like the pulsed wire method [1,2], it gives in one measurement the magnetic field variation along the entire length of the electromagnetic wiggler. In addition it is possible to also measure, instantaneously, the distribution of the magnetic field across the lateral dimension of the wiggler. Our method is based on the use of a magnetic recording tape which is inserted into the gap of the electromagnetic microwiggler. The maximum local magnetic field produced during the driving-current pulse is recorded on the tape at all axial and lateral positions. The tape containing the recorded magnetic field can then be read (and “heard”) by an ordinary tape recorder.

Conventional high-density digital recording using a rotary head requires a high-accuracy servo system with a high precision in mechanics. By combining double-track scanning and data rearrangement, a nontracking method by which all data can be reproduced in order has been developed. By using this method, it is shown that a tracking accuracy of ± 100 μm for a track pitch of 9.8 μm is obtained compared to a conventional value of ±5 μm. A stamp-sized cassette and a compact digital audio tape recorder are developed using this nontracking method and evaporated metal tapes.

In this paper, an analysis technique is presented for block oriented data formats in digital tape recording systems. The approach determines format parameters that maximize the information storage density at a specified failure rate. In the process, it is also shown that block interleaving is not beneficial for many systems.

We apply Golay (1961) complementary sequences for measuring the impulse response and the amplitude and phase transfer functions of a linear magnetic tape recording channel. Our experimental channel suffers from nonlinear distortion caused by a magnetoresistive sensor. The measured characteristics, in particular the amplitude transfer function, show a better performance than the same characteristics obtained with the de facto standard impulse response measurement technique using feedback shift register sequences. Based on a practical nonlinear Volterra model of our experimental tape recording channel, we analyze the artefacts due to second and third order nonlinear distortion which can occur in the Golay impulse responses and transfer functions.

Two important classes of problems arise when long-term (more than a decade) archival storage of magnetic tape recording is undertaken. They include relatively minor concerns over the physical integrity of the software (the tapes themselves) and unresolvable major concerns over the long-term continued availability of the proper hardware (the playback machines themselves) which are needed to make the archival tape usable. In view of this, video recording systems as well as computer data recording systems are examined. The archival stability of modern tapes is assessed, and the archival stability of modern recorders is discussed. >

Magnetic tape recording for data storage is reviewed with respect to the rapidly advancing areal density of recorded data on tape. The key to these advances lies primarily in the ability of heads and media to support this growth, coupled with a move to active track following servo control and advanced recording channels. Multi-element magnetic head devices in the form of arrays of thin film record (write) heads using high moment soft magnetic materials and multilayer magnetoresistive (MR) readback devices are emphasized.

Improvements to a method of calibrating a high-density tape recording system are suggested. The small gap approximation is not made, and allowances for the effects of demagnetization are included. A better and smaller estimate of the effective head-media spacing is obtained. >

The effect of head saturation on the signal spectrum in high-density tape recording has been investigated using a simple model for the recording process and a finite-difference model for the head. Phase relationships in the recording process are incorporated by utilizing the angularly dependent switching behavior of a two-particle simplified system. The recording process under saturation is shown to depend on the achievable deep gap field since the head field shape changes only slightly. Scanning-Kerr-microscope assessment of saturation is shown to differ from that of a micro-loop. >

Various limitations in the design of recording heads are reviewed. Track definition and gap length, the need for small heads and possible improvements in the shape of heads, coil chambers and magnetic flux guides, and the requirements for the materials to be used in metal-in-gap heads and sandwich heads are considered. With respect to future development, it is predicted that higher density will require shorter gaps (the present gaps can be made shorter without much effort), higher B/sub s/ values for writing at long wavelengths, and higher mu for efficient reading with short-gapped heads. >

Television tape recording of fluoroscopic images is by no means new (5, 6). Until relatively recently, owever, such recording required large expensive television tape recorders under constant skilled pervision by technical and engineering personnel. This placed their use out of the reach of all but very large specialized institutions. With the advent of transistorized, compact helical scan recorders, the size and price limitations have been largely overcome. Such devices are now within the reach of the clinical radiologist in the community hospital or private office practice. Since August, 1963, it has been our custom to employ a video tape-recording device routinely in our luoroscopic procedures. During this period, many radiologists have shown considerable interest in this modality. This interest has prompted a review of the subject and a comparison of its merits with those of the other means of physiologic recording, cineradiography. I t is neither possible nor desirable to attempt to give an elaborate...

In order to keep a record of stroboscopic images, we developed a video-tape recording system. This system can be utilized in the following manners:(1) The physician can use not only verbal but also visual means of explanation of the patient's laryngeal condition.(2) Teaching the various aspects of vocal fold vibration can be enhanced with the use of this dynamic method.(3) More accurate information can be gleaned by allowing for more than one specialist to view the vocal fold in motion at the same time. In addition, this system permits repeated viewings at convenient times.(4) One can compare vibratory patterns between different time points, including pre- and post-therapeutic examinations.We also developed an additional system with which any waveforms displayed on an oscilloscope can be superimposed on the stroboscopic images.

As bit and track densities increase, more complex detection schemes must be devised to combat the nonlinearities inherent in high-density magnetic-recording channels. With an accurate model we can quantify the departure of the channel from linear superposition, leading to optimized detectors providing improved system performance. Two distinct models have been developed. The first attempts to account for many nonlinear effects created by the physical properties of the medium; the other tries to combine all of these effects into a simple nonlinear function. Both models show excellent agreement using parameters derived from experimental signals. Simpler detection schemes result from the second model, while the first, more complex, model ensures preservation of generality. Apart from devising nonlinear detectors, we can also generate pseudo-random signals with enhanced nonlinear distortions, which may be used to test the robustness of various detection schemes. In this paper we present the results of parameter extraction and nonlinear distortion for several magneto- resistive tape-recording channels at a wide range of densities.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

A relatively simple magnetic tape recording system for recording scintillation scan data has been developed. One channel is used for storage of the pulses obtained by the scanning scintillation probe. Another channel is used to record the relative position of the end of each scan line. Scans may be played back, on the scanner itself, with different contrast settings to optimize the presentation of information obtained from radioisotope scans. Storage on magnetic tape also safeguards against instrument failure and human error.

A new tracking method for an optical tape recording system is described. Since it is difficult to form pits or grooves on tape media, we have employed crosstalk signals to detect tracking error. On the 2 tracks adjacent to the one that the focused spot must follow, pilot signals at 2 different frequencies are recorded respectively. When reading the track, the pilot signals from the 2 adjacent tracks are derived from the readout signal. The tracking error signal is generated by differential detection of their amplitudes. We carried out fundamental experiments using a rotating optical head and a magneto-optical recording medium sputtered on a flat glass substrate. A 5 micrometers mark length was available to detect the tracking error for a 2 micrometers track pitch. A total residual tracking error of less than 0.1 micrometers was obtained when the medium was displaced in a 2 micrometers peak to peak range.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Information in 51 tape-recorded physicianpatient encounters was compared with information written in the patients' medical records. Diagnoses, chief complaints, scheduled appointments, non-drug therapy, and diagnostic studies were uniformly well-recorded. Medication names were well-recorded but dosages were not. Characteristics of care such as levels of function, probable cause of illness, reason for follow-up, and compliance were recorded poorly. Patients were more likely to know about and understand their diagnosis, and names, dosage, and intended function of their medications when this information was written in the record than when it was not. These findings indicate a relationship between the quality of medical records and the effectiveness of care.

A new optical tape recorder, based on a very fast rotating polygon is described. This system combines a high data rate with a high storage density and fast access. The recorder is compact and, apart from the polygon, requires only simple mechanics.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

In this paper several formatting solutions which trick mode (fast forward, fast reverse) support for helical scan recording are proposed. First, two basic methods where the trick mode signal is built up from semi-random sections of the normal stream, will be discussed. These low complexity methods form the basis for the extension to more advanced solutions that employ a dedicated bit stream for trick modes. A method of formatting this dedicated trick stream on a recorder without phase lock between the scanner and the tape during fast forward is presented by means of three separate case studies. In order to guarantee that the trick mode stream is read at the chosen speed multiple copies of the same stream need to be placed at well chosen places on the tape. This solution is extremely attractive for systems where a limited number of speedup levels are required. Recorders that can perform phase locking during fast forward yield a particular advantage for high speed-up (n equals 12, 18, ...) factors and allow for the support of more distinct speedup levels.

1. Our impressions of orthicor and vidicon television systems coupled with tape recording are compared with cinefluorographic methods. We have chosed orthicon television with a transistorized portable tape recorder as the best system for general departmental use.2. Normal bronchial dynamics as demonstrated with the above system are presented in apnea and quiet respiration, deep respiration and coughing. Preliminary observation of dynamic abnormalities is mentioned.