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An input unit designed for the BESM-3M general-purpose digital computer is described. The input unit uses a standard MEZ-28A studio tape recorder. An automatic data-input subroutine is presented.
The magnetic tape recorder has played an essential role in the capture and storage of instrumentation data for more than thirty years. During this time, data recording technology has steadily progressed to meet user demands for more channels, wider bandwidths, and longer recording durations. When acquisition and processing moved from analog to digital techniques, so recorder design followed suit. Milestones marking the evolution of the data recorder through these various stages - multi-track analog, high density longitudinal digital, and more recently rotary digital - have often represented important breakthroughs in the handling of ever-greater quantities of data. Throughout this period there has been a very clear line of demarcation between data storage methods in the 'instrumentation world' on the one hand and the 'computer peripheral world' on the other. This is despite the fact that instrumentation data, whether analog or digital at the point of acquisition, is now likely to be processed on a digital computer at some stage. Regardless of whether the processing device is a small personal computer, a workstation, or the largest supercomputer, system integrators have traditionally been faced with the same basic problem - how to interface what is essentially a manually controlled, continuously running device (the tape recorder) into the fast start/stop computer environment without resorting to an excessive amount of complex custom interfacing and performance compromise. The increasing availability of affordable high power processing equipment throughout the scientific world is forcing recorder manufacturers to make their latest and perhaps most important breakthrough - the computer-friendly data recorder. The operating characteristics of such recorders are discussed and the resultant impact on both data acquisition and data analysis elements of system configuration are considered.
Tape recorders employed to record and eventually reproduce digital data introduce errors into the data. It is desirable to understand the sources of these errors so that predictions may be made of the resultant error rate. While specific predictions are difficult to apply to whole classes of machines and their respective electronic systems, it is possible to make general predictions which give insight into the problems and processes involved. A heuristic viewpoint is developed for understanding the problems involved in machines and systems that now exist.
Disk Recording System (DRS) is a systems-integration computer program for a direct-to-disk (DTD) high-speed data acquisition system (HDAS) that records rocket-engine test data. The HDAS consists partly of equipment originally designed for recording the data on tapes. The tape recorders were replaced with hard-disk drives, necessitating the development of DRS to provide an operating environment that ties two computers, a set of five DTD recorders, and signal-processing circuits from the original tape-recording version of the HDAS into one working system. DRS includes three subsystems: (1) one that generates a graphical user interface (GUI), on one of the computers, that serves as a main control panel; (2) one that generates a GUI, on the other computer, that serves as a remote control panel; and (3) a data-processing subsystem that performs tasks on the DTD recorders according to instructions sent from the main control panel. The software affords capabilities for dynamic configuration to record single or multiple channels from a remote source, remote starting and stopping of the recorders, indexing to prevent overwriting of data, and production of filtered frequency data from an original time-series data file.
An investigation is described into the laboratory measurement and analysis of pyrotechnic shock which was prompted at JPL when two separate facilities generated discrepant pyrotechnic shock data while testing Mariner Jupiter/Saturn 1977 spacecraft hardware. Both of the testing facilities were surveyed. The only difference noted was in the FM tape recorders used to record the data. One facility used a tape recorder operating at 60 in./sec with a frequency response of 20 kHz; the other used a tape recorder operating at 120 in./sec with a frequency response of 80 kHz. The accelerometers, cables, charge amplifiers, and mechanical setups were identical.
High-speed, single-shot, transient voltage is recorded on a video tape recorder, which, when played back, converts the single signal to a repetitive signal. This drives a sample data translator which lengthens the original transient production time, suiting it to an x-y plotter or computer tape recorder use.
Adaptation of field infrared terrain analysis spectral correlation program to IBM 7090 and recording tape voltage drift correction procedures
Continuous loop magnetic tape recorders used in Vanguard, Tiros and Nimbus satellites
An investigation of laboratory measurement and analysis of pyrotechnic shock is described which was prompted when two separate facilities produced discrepant pyrotechnic-shock data while testing Mariner Jupiter/Saturn 1977 spacecraft hardware. Both testing facilities are thoroughly examined to find a possible cause for the discrepancies, and it is noted that one facility incorporated an FM tape recorder operating at 60 in./sec with a frequency response of 20 kHz while the other incorporated a tape recorder operating at 120 in./sec with a frequency response of 80 kHz. It is found that the discrepancies were a direct result of the inadequate recording frequency response of the tape recorders. Other factors involved in obtaining more accurate data are discussed.
This report presents the methodology used for receiving, processing, and analyzing flight data from the Space Transportation System at NASA Langley Research Center (LaRC) on a near real time basis. The task was performed in October 1993 during the STS-58 mission using data from the Orbital Acceleration Research Experiment (OARE). The transmitting and receiving of OARE data on a near real time basis at LaRC were highly successful. The time to receive and record the data from the payload tape recorder required 20 to 30 minutes. Payload tape recorder data were downlinked at intervals of 4 to 6 hours rather than continuously. The quality check of the data at LaRC required 2 minutes. Four to 5 minutes of time was required to obtain preliminary acceleration levels of the Orbiter that are within 1 micro-g of the absolute accelerations This demonstration has shown that, with operational modifications LaRC has the capability to serve as a User Operation Center for receiving and processing flight data from the Space Shuttle and Space Station.
In order to provide transparent access to data in network computing environments, high performance storage systems are getting smarter as well as faster. Magnetic tape instrumentation recorders contain an increasing amount of intelligence in the form of software and firmware that manages the processes of capturing input signals and data, putting them on media and then reproducing or playing them back. Such intelligence makes them better recorders, ideally suited for applications requiring the high-speed capture and playback of large streams of signals or data. In order to make recorders better storage systems, intelligence is also being added to provide appropriate computer and network interfaces along with services that enable them to interoperate with host computers or network client and server entities. Thus, recorders are evolving into high-performance storage systems that become an integral part of a shared information system. Data tape has embarked on a program with the Caltech sponsored Concurrent Supercomputer Consortium to develop a smart mass storage system. Working within the framework of the emerging IEEE Mass Storage System Reference Model, a high-performance storage system that works with the STX File Server to provide storage services for the Intel Touchstone Delta Supercomputer is being built. Our objective is to provide the required high storage capacity and transfer rate to support grand challenge applications, such as global climate modeling.
Tape capstan drive motor speed controlled by phase-locked loop to keep data rate off of tape compatible with demand clock rate preventing deskewbuffer overflow or underflow. Immunity to speed perturbations caused by data dropouts is obtained by switching to different data-channel reference signal whenever dropout is detected by frame synchronizer in channel currently in use. Desired tape speed is selected by changing frequency of demand rate clock and changing divisor N in programable divider.
Studies of tape recorder failure modes in spacecraft tape-recorder applications reveal that failures within the mechanical transport package far outnumber those of the associated electronics. It would, therefore, be desirable to simplify the transport mechanism and to separate the moving parts with a continuously fresh supply of a single inert lubricant medium. The suggestion is made to replace the ball bearings with hydrostatically pressurized fluid film bearings.
Work with a state-of-the-art high density PCM tape recorder reproducer system is described. The tape recorder is designed for 80 Mb/s operation at an overall bit error rate of .00001and for 40 Mb/s operation at .000001. The article describes the process of measuring the error rate. Also detailed is a data rate buffer designed for use in recent radar experiments and generalizable to most potential uses of the recorder system.
Linear frequency domain methods are inadequate in analyzing the 1975 Viking Orbiter (VO75) digital tape recorder servo due to dominant nonlinear effects such as servo signal limiting, unidirectional servo control, and static/dynamic Coulomb friction. The frequency loop (speed control) servo of the VO75 tape recorder is used to illustrate the analytical tools and methodology of system redundancy elimination and high order transfer function verification. The paper compares time-domain performance parameters derived from a series of nonlinear time responses with the available experimental data in order to select the best possible analytical transfer function representation of the tape transport (mechanical segment of the tape recorder) from several possible candidates. The study also shows how an analytical time-response simulation taking into account most system nonlinearities can pinpoint system redundancy and overdesign stemming from a strictly empirical design approach. System order reduction is achieved through truncation of individual transfer functions and elimination of redundant blocks.
A data system is designed to permit the simultaneous recording of 90 data channels on one 28 track magnetic tape recorder using a constant bandwidth FM multiplexing technique. Dynamic signals from transducers located in the test aircraft are amplified and fed to voltage controlled oscillators where they are converted to discrete FM signals. The signals from each group of five VCO's are fed to a mixer/distribution amplifier where they are combined into one composite signal and recorded, using direct recording techniques, on one magnetic tape recorder track. Millivolt signals from the recorders reproduce heads are amplified to one volt and then electronically switched to an FM demultiplexing system where appropriate frequency discrimination and signal filtering recover the original analog information.
Current operational capabilities of tape recording for Very Long Baseline Interferometry (VLBI) at the Haystack Observatory allow 0.7 terabytes (12 hours at 128 Mb/s) of data to be stored in a 128 cu. inch volume. On-going efforts are aimed at full time 1 Gb/s operation with two 36-channel headstacks. Applications for linear digital tape recording, with suitable development of thin-film head arrays, suggest a volume density exceeding 1 TB/cu. inch to be achievable in the future.
The effects of external mechanical and climatic actions on the efficient operation of magnetic tape recording equipment are analyzed. The efficiency and reliability of the recording system are determined by the structural parameters and the characteristics of the individual elements of the transport mechanism circuit. The resistance of tape recording equipment to the effects of vibration is considered essential for reliable operations. Methods for insuring reliable tape transport and recording action are discussed.