Process (computing) | EPFL Graph Search

In computing, a process is the instance of a computer program that is being executed by one or many threads. There are many different process models, some of which are light weight, but almost all processes (even entire virtual machines) are rooted in an operating system (OS) process which comprises the program code, assigned system resources, physical and logical access permissions, and data structures to initiate, control and coordinate execution activity. Depending on the OS, a process may be made up of multiple threads of execution that execute instructions concurrently. While a computer program is a passive collection of instructions typically stored in a file on disk, a process is the execution of those instructions after being loaded from the disk into memory. Several processes may be associated with the same program; for example, opening up several instances of the same program often results in more than one process being executed. Multitasking is a method to allow multiple

The mean-field behavior of processor sharing systems with general job lengths under the SQ(d) policy

Arpan Mukhopadhyay

This paper addresses the mean-field behavior of large-scale systems of parallel servers with a processor sharing service discipline when arrivals are Poisson and jobs have general service time distributions when an SQ(d) routing policy is used. Under this policy, an arrival is routed to the server with the least number of progressing jobs among d randomly chosen servers. The limit of the empirical distribution is then used to study the statistical properties of the system. In particular, this shows that in the limit as N grows, individual servers are statistically independent of others (propagation of chaos) and more importantly, the equilibrium point of the mean-field is insensitive to the job length distributions that has important engineering relevance for the robustness of such routing policies used in web server farms. We use a framework of measure-valued processes and martingale techniques to obtain our results. We also provide numerical results to support our analysis. (C) 2018 Elsevier B.V. All rights reserved.

ELSEVIER SCIENCE BV2018

Scaling Out Bioinformatics in the Data Center

Sam David Whitlock

Whole Genome Sequencing is a process in the field of bioinformatics that transforms biological samples of DNA into an electronic dataset of genetic bases. The process consists of two sequential components. First, the laboratory process of sequencing transforms the biological DNA samples into a digital format by transcribing the sequence of bases that make up short snippets of DNA. Second, a genomic workflow uses software to transform this data into a representation that is useful for genomic analysis. Recent advancements in High-Throughput Sequencing technology enable the laboratory phase to produce data faster and at a lower cost than prior techniques were capable of. The applications and file formats used in workflows have not undergone commensurate technological advancement in order to accommodate this deluge of genomic data. This thesis introduces a redesign of genomic workflows, their component applications, and the underlying file formats in order to scale out workflows across a data center. The design builds upon on two design components. First, a unified file format supplants the myriad existing formats in order to accommodate scale-out multi-machine I/O. The file format imposes minimal feature requirements upon the storage system, thereby enabling its use in high- performance systems for processing and cost-effective cold storage systems for long-term storage. Second, a new cloud computing framework provides an API for composing workflows in an abstract logical description and delegating the execution of the logic to a common runtime. The framework's runtime executes the logical workflow description on scale-out hardware resources while abstracting the execution details. We combine the file format and framework to build a new set of workflows that scale out across data center resources. These scale-out workflows incorporate existing workflow applications (compartmentalized into libraries that the framework invokes) and new applications that leverage the features provided by the scale-out architecture. All workflows delegate work distribution and task concurrency to the framework's runtime and utilize a common set of subcomponents for auxiliary code (e.g., I/O with various storage systems, processing different file formats). These workflows are able to scale out across a data center to the point of saturating the throughput of one or more hardware resources.

EPFL2019

Assemblage form

Trevor Patt

The thesis proposes a projective theory for contemporary urbanism that equates the active processes of the city and a new orientation for procedural urban design within a single line of thought that delineates the concept of a generic organizationâone that derives from unitary operations acting in series, forming heterogeneous assemblages, but resisting the tendency to totalizing systematization. Such a description characterizes the urban condition as an open phenomenon, such as that described by theorists of assemblage urbanism. This thesis extends this work from an analytical or empirical theory to an operative one that can be applied to design practice by combining it with an ontology of encapsulation and object-based agency. I will argue that computational processes are unique in the way that they enable urban design to operate in the same manner as the city with regard to enaction and representation while drawing attention to the rhetorical dimension of interactive systems like urbanism and procedural models. These parallels are further explored through a series of themes that bridge between urban studies and urban design and that connect to historical concerns in computation and urban design. The four themesâInteractive, Generative, Reflexive, Entropicâcoalesce around a coherent, integrated theoretical schema. Within this framework, I also argue for an increasingly involved role for architecture as an active agent in the urban design process. Illustrations of how this might occur (as functional code and software screenshots) are presented alongside the arguments to underscore the fact that the material basis of the computational model is as significant a determinant of design practice as the material realities of the city are to the urban experience. Finally, these lessons are imported back into urbanism with architecture serving as an interface to the city. Procedural engagement allows architecture to participate in urbanism through an inextricably and mutually contingent interaction. In cases where this occurs, the city continuously prompts architecture to carry out new inquiries into the changing potential of the urban situation, without providing a terminal condition. Rather, by allowing the the outcome of the situation to remain undecided, both urbanism and computational modeling can be seen to offer the same productive irreality and alterity: an urban generic.