Interrupt Mechanism Research Articles

POWER2 fixed-point, data cache, and storage control units

The POWER2™ fixed-point, data cache, and storage control units provide a tightly integrated subunit for a second-generation high-performance superscalar RISC processor. These functional units provide dual fixed-point execution units and a large multiported data cache, as well as high-performance interfaces to memory, I/O, and the other execution units in the processor. These units provide the following features: dual fixed-point execution units, improved fixed-point/floating-point synchronization, new floating-point load and store quadword instructions, improved address translation, improved fixed-point multiply/divide, large multiported D-cache, increased bandwidth into and out of the caches through wider data buses, an improved external interrupt mechanism, and an improved I/O DMA mechanism to support multiple-streaming Micro Channels®.

Mechanism of interruption of atrial flutter by moricizine. Electrophysiological and multiplexing studies in the canine sterile pericarditis model of atrial flutter.

Moricizine is said to have potent effects on cardiac conduction but little or no effect on cardiac refractoriness. The effects of moricizine (2 mg/kg IV) on induced atrial flutter were studied 2 to 4 days after the creation of sterile pericarditis in 11 dogs. Ten episodes of stable atrial flutter before and after the administration of moricizine were studied in 9 dogs in the conscious, nonsedated state, and 7 episodes were studied in 6 dogs in the anesthetized, open chest state. In the conscious state, the effects of moricizine on atrial excitability, atrial effective refractory period, and intra-atrial conduction times were studied by recording during overdrive pacing of sinus rhythm from epicardial electrodes placed at selected atrial sites. Moricizine prolonged the atrial flutter cycle length in all the episodes, from a mean of 133 +/- 9 to 172 +/- 27 milliseconds (P < .001), and then terminated 7 of the 10 episodes. Moricizine increased the atrial threshold of excitability from a mean of 2.3 +/- 1.4 to 3.3 +/- 2.2 mA (P < .01) and prolonged intra-atrial conduction times (measured from the sulcus terminalis to the posteroinferior left atrium) from a mean of 58 +/- 6 to 64 +/- 5 milliseconds (P < .005). Prolongation of the atrial effective refractory period from 166 +/- 20 to 174 +/- 24 milliseconds (P < .05) was observed only at the sulcus terminalis site. In the open chest studies, administration of moricizine prolonged the atrial flutter cycle length from a mean of 150 +/- 15 to 216 +/- 30 milliseconds (P < .001) and then terminated the atrial flutter in all 7 episodes. As demonstrated by simultaneous multisite mapping from 95 bipolar sites on the right atrial free wall, the atrial flutter cycle length prolongation was either due to further slowing of conduction in an area of slow conduction in the reentrant circuit of the atrial flutter (5 episodes) or further slowing of conduction in an area of slow conduction plus the development of a second area of slow conduction (2 episodes). The change in conduction times in the rest of the reentrant circuit was negligible (10.9 +/- 8.7% of the total change). In all 7 episodes, the last circulating reentrant wave front blocked in an area of slow conduction. Moricizine (1) prolongs the atrial flutter cycle length, primarily by slowing conduction in an area of slow conduction in the reentrant circuit, (2) terminates atrial flutter by causing block of the circulating reentrant wave front in an area of slow conduction of the reentrant circuit, and (3) effectively interrupts otherwise stable atrial flutter in this canine model. The reason for these effects of moricizine are not readily explained by its effects on global atrial conduction times and refractoriness studied during sinus rhythm. Local changes in conduction in an area(s) of slow conduction are responsible for both cycle length prolongation and atrial flutter termination rather than the traditional wavelength concept of head-tail interaction.

Micro controller-based digital filter implementation using an Intel 8097

A digital filter design based on a 16-bit single chip microcontroller is described. The hardware for this signal processing system employs the Intel 8097 microcontroller and some glue logic. The software, which implements the digital filter algorithm, is based on the microcontroller's interrupt mechanism. A design example of a digital notch filter using the bilinear z-transform method is presented together with its test results.

Transient current interruption mechanism in a magnetically delayed vacuum switch

The capacity of a magnetically delayed vacuum switch to conduct current depends on the density of plasma injected into the switch. Exceeding the current capacity results in the switch entering a lossy mode of operation characterized by a transient interruption of the main current (opening behavior) and a rapid increase of voltage across the vacuum gap. Streak and framing photographs of the discharge indicate that a decrease of luminosity near the middle of the gap precedes the transition to the opening phase. The zone of low luminosity propagates toward the cathode. This evidence suggests that the mechanism causing the opening phase is erosion of the background plasma in a manner similar to that in a plasma-opening switch. The resulting ion depletion forces a space-charge-limited conduction mode. The switch inductance maintains a high discharge current even during the space-charge-limited conduction phase, thus producing high internal fields. The high accelerating voltage, in turn, produces electron and ion beams that heat the electrode surfaces. As a result of the heating, jets of electrode vapor issue from the electrodes, either cathode or anode, depending on the selection of electrode materials.

Structured interrupts

In this paper I refine the concept of interrupt to define a more structured mechanism with straightforward semantics. Some commonly implemented interrupt mechanisms are reviewed; their semantics are deduced and analyzed. I show how a different understanding of interrupts resolves the deficiencies of existing interrupt mechanisms and provides the programmer with powerful tools for addressing real-time and multiprocessing problems. On this basis a recommendation is made for architectural and operating system support of the improved interrupt mechanism.

A new reactive operating system for human-robot interaction

Robots which interact and cooperate with humans are required to be sensitive to changes of their surrounding environment for handling physical resources and supporting open and distributed human-robot-computer systems. But it is difficult to incorporate sensitivity into real-time systems, and to identify the owner of a physical resource in an open and distributed human-robot-computer society. In this paper, we formulate a physical ownership model which is a possible solution to the managing of physical resources among humans and robots. Then we present a reactive operating system PULSER which supports the implementation of the model. A new interrupt mechanism is proposed to support sensitivity with real-time facility and a physical resource manager is implemented to support the ownership model. Also, we describe a new facility for wireless communication in open and distributed systems.

Study of high current commutation by explosive switch

The basic experimental data obtained with a large current opening switch for current commutation using explosives are presented. The experimental results show that currents up to a maximum of 40 kA can be completely interrupted within 30 mu s. The mechanism of current interruption using a thin conductor plate and methods of measuring interrupting current with a pick up coil and taking photographs with a high-speed camera (1 frame/ mu s) are discussed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

VICbus: VME inter-crate bus-a versatile cable bus

VICbus is a multiplexed multimaster cable bus primarily intended for interconnecting backplane bus systems, such as VMEbus, but which may also be used wherever a high-performance, general-purpose cable bus is required. It is implemented using differential line transmission to interconnect up to 31 devices on a total cable length of 100 m. Both compelled (asynchronous) and noncompelled (synchronous) data transmission protocols are specified. An efficient bus arbitration mechanism takes into consideration the long signal propagation times on cables. A simple interrupt mechanism permits the transparent use of interrupts on interconnected VMEbus backplanes. The data transfer protocols, bus arbitration, interrupts, register, and implementation details are discussed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Incidence and mechanism of interruption of reentrant ventricular tachycardia with rapid ventricular pacing.

Information concerning the electrophysiological characteristics of the reentrant circuit is still limited. To understand the incidence and mechanism of pacing-induced interruption of ventricular tachycardia (VT), rapid pacing was performed to entrain VT, and the local electrogram at the VT origin and the surface electrocardiogram were analyzed. Among 25 patients, evidence of transient entrainment was confirmed in 20 patients, but the critical paced cycle length at which VT was interrupted was obtained in 13 patients when the paced cycle length was decreased in steps of 10 msec. During pacing at the critical cycle length (defined as block cycle length), changes in the local electrogram at VT origin were confirmed in all of the 13 patients; that is, 1) a change in morphology and 2) a change in the timing of activation: a sudden shortening in the stimulus to local electrogram time (third entrainment criterion by Waldo). The two changes mean that the exit is activated from a different direction (retrograde capture) because of an orthodromic block in the slow conduction zone. The QRS complex in the surface electrocardiogram showed a change in configuration from the fusion complex to the fully paced one at the same time when the exit was captured antidromically. Based on our observations in these patients, ventricular tachycardia interruption is very often associated with orthodromic block in the reentrant circuit at a critical cycle length of rapid pacing.

PGF2 α, PGE 2, and sex steroids from the abdominal gland of the male crested newt Triturus carnifex (Laur.)

Prostaglandin F 2 α ( PGF 2 α ), prostaglandin E 2 (PGE 2), progesterone, androgens, and 17 β-estradiol in vitro release by the abdominal gland of the crested newt, Triturus carnifex (Laur.), was studied during the prereproductive, reproductive and postreproductive periods. In addition, the in vitro effects of the PGF 2 α and/or PGE 2 on progesterone, androgens and estradiol release by the abdominal gland were evaluated. PGF 2 α , PGE 2 and progesterone release was higher during the reproductive period, and in the same period, PGE 2 treatment induced a progesterone increase. PGF 2 α induced an increase of abdominal gland estradiol release at the end of the reproductive period. These results seemed to confirm the pheromonal role assigned to progesterone, and suggested a PGE 2 stimulatory role in inducing progesterone release, even if pheromonal activity of PGF 2 α and PGE 2 cannot be excluded. In addition, PGF 2 α -dependent estradiol increase at the end of reproduction could be interpreted as a mechanism for interruption of the abdominal gland activity.

Identity Processes and Social Stress

Social stress can be understood by incorporating interruption theory as developed in research on stress into a model of processes drawn from theory. From this perspective, social stress results from interruption of the feedback loop that maintains processes. I discuss four mechanisms of interruption of processes: broken loops, interference between systems, over-controlled systems, and the invocation of episodic identities. Each of these four mechanisms is associated with conditions known to produce feelings of distress. Finally, I discuss how personal evaluation relates to processes and distress, and how distress can lead to changes in identity. T hirty years ago inldentity andAnxiety, Stein, Vidich and White (1960) expressed the concern that the advent of a mass society would lead to a loss of identity and hence to widespread anxiety or stress. Today, research on social stress is more likely to emphasize the excessive demands and pressures arising from the many roles and identities that people maintain (Holroyd and Lazarus 1982; House 1974). While the implicit contradiction between these contrasting themes of too few or too many identities has not yet been resolved, interest in the relationship between stress or anxiety and has grown. In this paper, I propose a model of the relationship between stress and identity. I show that in a variety of situations known to produce stress, stress results from a common mechanism: disruption of the process. The importance of this common mechanism is two-fold. First, from the point of view of theory, it underlines the importance of understanding as a continuous process rather than as a state or trait of an individual. Second, it gives a focus to research on coping and problem solving as mechanisms for dealing with anxiety and distress. While Thoits (1991) has recently suggested that life events related to identities are more likely to produce distress than other life events, the present paper presents a model that helps to clarify this link.

Investigation of the Laminate Structure of Lumbar Disc Anulus Fibrosus

The structure of the lumbar disc anulus fibrosus was investigated using a layer-by-layer peeling technique and microscopic examination of various cut surfaces. Anulus specimens from spines of two different age groups and from two levels, L2-3 and L4-5, were examined. The vertebra-disc-vertebra units were subjected to intentional controlled dehydration to enhance the visual contrast between the white opaque fiber bundles and the translucent ground substance. The variations of the anulus structure with circumferential and radial locations were studied. The following principal structural features were quantified: 1) the anulus, excluding the transition zone, consists of 15 to 25 distinct layers, depending on the circumferential location, the spine level, and the specimen age; 2) in any 20 degrees circumferential sector, nearly half of the layers terminate or originate, thereby causing local laminate irregularities; 3) there are two identifiable mechanisms of layer interruption at these irregularities; 4) the thickness of individual layers varies both circumferentially and radially and increases markedly with age; and 5) the number of fiber bundles over the total height of the disc varies from 20 to 62, with an average interbundle spacing of 0.22 mm.

Fracture mechanism and martensite phase distribution in the zones of plastic deformation of N26Kh5T3 steel aged according to an interrupted mechanism

1. Impact fracture of steel is accompanied by formation of two forms of microrelief corresponding to areas of interrupted decomposition and to areas free of it. In the first case an acicular microrelief is formed at all test temperatures. Embrittlement of the areas in which interrupted decomposition did not occur with a reduction in temperature is apparently related to formation of martensite phase. 2. In movement from the surface of impact fractures into the depth of the specimen the quantity of α-martensite continuously decreases, reaching a minimum at the boundary of the micro- and macrozones of plastic deformation in the fractures of specimens tested at negative temperatures. In specimens tested at normal temperature α-martensite is formed only on the surface of the fractures. In the weakly deformed macrozone of low-temperature fractures a small quantity of α- and e-martensite is observed. 3. Local heating of the material has a significant influence on the phase transformations in the zones of plastic deformation at the tip of a propagating crack.

Atrial automatic ectopic tachycardia successfully treated with encainide in a 4-week-old infant after Senning procedure

ly 310 ms, the flap reached the anterior wall of the ascending aorta and the murmur almost disappeared coincidentally. The flap remained in this position until the following systole (Fig. 2). Color Doppler flow imaging revealed that the aortic regurgitant jet extended along the anterior mitral leaflet only during early diastole (Fig. 3). It was also demonstrated that the intimal flap obstructed the aortic root during late diastole, resulting in interruption of regurgitation. Cardiac surgery, after 1 month, disclosed a small entry of dissection at the aortic arch. There was no entry just above the aortic valve. The ascending aorta was replaced by a graft, and. the aorttc valve was resuspended and refixed. Aortic regurgitation is one of the major complications of dissecting aneurysm of the ascending aorta.’ In our case, it was significant that the aortic regurgitant murmur disappeared abruptly at early diastole. The mechanism of interruption of aortic regurgitation was the aortic root obstruction by the intimal flap. Inasmuch as the entry located at the aortic arch and the false lumen had a blind end above the aortic valve, the blood through the entry bulged the false lumen fully from mid to late diastole in the ascending aorta, resulting in interruption of aortic regurgitation. This led to a time lag between the aortic valve closure and the upward motion of the intimal flap. Thus, regurgitant volume was minimal, and the patient’s condition seemed to remain stable until surgical repair. Sraow et al2 reported one case of intimal flap prolapse from the aortic root into the left ventricle causing aortic regurgitation with proper coaptation. To our knowledge, the present case is the first one of intimal flap reduction of aortic regurgitation. This unique pathophysiology could be demonstrated by echoDoppler examinations. Among echo-Doppler examinations, color Doppler flow imaging can demonstrate intracardiac structures and blood flows simultaneously in real-time imaging and is, therefore, of great value in diagnosis of this particular aortic regurgitation.

Process oriented programming

This paper argues that co-routines are related to concurrent processes. By adding interrupt mechanisms languages containing co-routine mechanisms can be used for concurrency. It is also the intention to bring some of the terminology used in Simula constructs to the attention of others dealing with concurrency in object oriented languages. The use of processes to avoid global states in user interfaces are shortly commented upon.

Instrumentation design for high-voltage electrical injury studies.

The experimental study of high-power electrical injuries requires special devices to protect personnel and data recording instruments. A power distribution system is described which was designed to apply 500-20000 V and currents up to 100 A to an experimental preparation and a measurement system for recording 0.02-200.0 V at local sites in the preparation. Data collection and storage are automated with analog and digital devices that minimize personnel contact. For personnel safety, all recording instruments are isolated from the power distribution system by battery-driven standby power supplies and from the experimental high voltages by fiber optic data links. Current-triggering and- interruption mechanisms allow variable-duration voltage applications as short as 25 ms. These applications are also synchronized to the electrocardiogram and can be made to occur during any part of the cardiac cycle. >

Performance Evaluation Method for interprocessor interrupts by message passing

A performance evaluation method for an inter-processor interrupt mechanism in a shared bus multi-microprocessor system is studied. In this mechanism, each processor has a register, i.e. message box, to which other processors can write a message via a shared bus. In addition, each message written into a processor's message box causes an interrupt. A generalized stochastic Petri net (GSPN) model is proposed for analyzing the above mechanism's behavior.

A microprocessor peripheral for a.c. motor position control

This paper describes the implementation of a position servo using an a.c. motor and an intelligent peripheral controller. The controller operates as a slave from the master processor and the communication between them are made by a dual-port RAM. An interrupt mechanism is used to perform speed and position measurements and inverter control.

Syntax and Defining Equations for an Interrupt Mechanism in Process Algebra1

A mechanism is introduced to describe priorities in ACP, the algebra of communicating processes, whereby some actions have priority over others in a non-deterministic choice (or sum). This mechanism can be used to model the working of interrupts in a distributed system. This is illustrated in an extensive example.

Discrimination of the mechanisms of cooxidation of arylalkanes and alkylamines

Numerical analysis of experimental data on the cooxidation of arylalkanes and alkylamines indicates a chain propagation and interruption mechanism with the participation of amine cation radicals. The steps corresponding to the classical cooxidation mechanism are excessive in this experiment.