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Results for “TIME SHARING”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1970

Instrumentation in a time-shared environment

Time shared computer system providing real time service to multiple laboratory instrumentation, discussing high speed channel, computer control and data abstracting techniques

Reynolds, W. E.↗
NASA NTRS1984

The Effects of Task Structure on Time-sharing Efficiency and Resource Allocation Optimality

A distinction was made between two aspects of time sharing performance: time sharing efficiency and attention allocation optimality. A secondary task technique was employed to evaluate the effects of the task structures of the component time shared tasks on both aspects of the time sharing performance. Five pairs of dual tasks differing in their structural configurations were investigated. The primary task was a visual/manual tracking task which requires spatial processing. The secondary task was either another tracking task or a verbal memory task with one of four different input/output configurations. Congruent to a common finding, time-sharing efficiency was observed to decrease with an increasing overlap of resources utilized by the time shared tasks. Research also tends to support the hypothesis that resource allocation is more optimal when the time shared tasks placed heavy demands on common processing resources than when they utilized separate resources.

Tsang, P. S.↗
NASA NTRS1985

Can pilots time-share better than non-pilots?

The time-sharing ability of 12 male pilots and 12 male college students ranging in age from 18-36 are evaluated and compared. The subjects performed five pairs of dual tasks with varying degrees of structural similarity; the test procedures are described. The time-sharing efficiency and resource allocation optimality of the subjects are analyzed. The data reveal that the pilots and students display similar time-sharing performance; the degree of time-sharing efficiency decreases and resource allocation optimality increases with an increasing degree of structural similarity between the time-shared tasks.

Tsang, P. S.↗
NASA NTRS1969

Time-shared Cathode Ray Tube

Time-shared cathode tube provides high quality display at low cost display stations which utilize television moniters. It updates a cluster of graphic displays from a computer and is useful in systems not equipped for graphics time-sharing.

Herndon, E. S.↗
NASA NTRS1975

Investigation of time-sharing of rebalance electronics for sensors in strapdown navigation platforms

This article reports the results of an investigation on time-sharing of a rebalance electronics among several sensors used in a strapdown navigation platform. Various concepts are given. The merits and demerits of the time-sharing for a typical situation are discussed in detail. A possible hardware realization is proposed. In addition, this study develops a general approach, applicable to other systems, for evaluating the use of time-sharing concept.

Coffman, D. E.↗
NASA NTRS1977

A comparison of time-shared vs. batch development of space software

In connection with a study regarding the ground support software development for the Space Shuttle, an investigation was conducted concerning the most suitable software development techniques to be employed. A time-sharing 'trial period' was used to determine whether or not time-sharing would be a cost-effective software development technique for the Ground Based Shuttle system. It was found that time-sharing substantially improved job turnaround and programmer access to the computer for the representative group of ground support programmers. Moreover, this improvement resulted in an estimated saving of over fifty programmer days during the trial period.

Forthofer, M.↗
NASA NTRS1982

The economics of time shared computing: Congestion, user costs and capacity

Time shared systems permit the fixed costs of computing resources to be spread over large numbers of users. However, bottleneck results in the theory of closed queueing networks can be used to show that this economy of scale will be offset by the increased congestion that results as more users are added to the system. If one considers the total costs, including the congestion cost, there is an optimal number of users for a system which equals the saturation value usually used to define system capacity.

Agnew, C. E.↗
NASA NTRS1969

A timed-shared digital filter realization

Special purpose computer organized as time-shared digital filter for real time applications with adaptable coefficients, programming and multiplexing scheme

Carroll, C. C.↗
NASA NTRS1975

Tracking performance under time sharing conditions with a digit processing task: A feedback control theory analysis

A one dimensional compensatory tracking task and a digit processing reaction time task were combined in a three phase experiment designed to investigate tracking performance in time sharing. Adaptive techniques, elaborate feedback devices, and on line standardization procedures were used to adjust task difficulty to the ability of each individual subject and manipulate time sharing demands. Feedback control analysis techniques were employed in the description of tracking performance. The experimental results show that when the dynamics of a system are constrained, in such a manner that man machine system stability is no longer a major concern of the operator, he tends to adopt a first order control describing function, even with tracking systems of higher order. Attention diversion to a concurrent task leads to an increase in remnant level, or nonlinear power. This decrease in linearity is reflected both in the output magnitude spectra of the subjects, and in the linear fit of the amplitude ratio functions.

Gopher, D.↗
NASA NTRS1983

On Why It Is Impossible to Prove that the BDX90 Dispatcher Implements a Time-sharing System

The Software Implemented Fault Tolerance SIFT system, is written in PASCAL except for about a page of machine code. The SIFT system implements a small time sharing system in which PASCAL programs for separate application tasks are executed according to a schedule with real time constraints. The PASCAL language has no provision for handling the notion of an interrupt such as the B930 clock interrupt. The PASCAL language also lacks the notion of running a PASCAL subroutine for a given amount of time, suspending it, saving away the suspension, and later activating the suspension. Machine code was used to overcome these inadequacies of PASCAL. Code which handles clock interrupts and suspends processes is called a dispatcher. The time sharing/virtual machine idea is completely destroyed by the reconfiguration task. After termination of the reconfiguration task, the tasks run by the dispatcher have no relation to those run before reconfiguration. It is impossible to view the dispatcher as a time-sharing system implementing virtual BDX930s running concurrently when one process can wipe out the others.

Boyer, R. S.↗
NASA NTRS1967

A user-oriented time-shared online system.

Computerized method for on-line data analysis, elucidating SLIP language, request, processing, interpretation, time sharing, background activity, etc

LANGUAGE PROGRAMMING↗