Unix System Calls

Basically all system calls return 0 or positive numbers when they succeed, and negative values are returned when they fail. Process User ID management system call format #include <unistd.h> unsigned short getuid () unsigned short getgid () unsigned short geteuid () unsigned short getegid () int setuid (int uid) int s ...

Basically all system calls return 0 or positive numbers when they succeed, and negative values are returned when they fail. The advanced operation of the stream poll the format of the system call #include <stropts.h> #include <poll> int poll (fds,nfds,timeout) struct POLLFD fds[]; * * Flow group description structure/unsigned long Nfds; /* Flow number */int timeout; ...

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This paper is an excerpt from the book "The Authoritative Guide to Hadoop", published by Tsinghua University Press, which is the author of Tom White, the School of Data Science and engineering, East China Normal University. This book begins with the origins of Hadoop, and integrates theory and practice to introduce Hadoop as an ideal tool for high-performance processing of massive datasets. The book consists of 16 chapters, 3 appendices, covering topics including: Haddoop;mapreduce;hadoop Distributed file system; Hadoop I/O, MapReduce application Open ...

Libexplain a library that can be used to explain UNIX and Linux system call errors. This will make your application error information more informative to the user. The library is not exactly an insert replacement for strerror, but it is close to each system calling a dedicated Libexplain feature. Libexplain 0.50 This release covers 173 system calls and 547 IOCTL requests. Example: FD = open (path, flags, mode);

In the past, we have introduced some principles of software development, such as the 10 commandments of high quality code and the UNIX design principles described in the UNIX legend (next article). I believe that you can learn from middle school some knowledge of design principles, as I said in the "How Do I Recruit procedures", a good programmer usually consists of its operational skills, knowledge level, experience level and ability four aspects. Here I would like to talk about some of the principles of design, I think these things belong to the long-term experience summed up knowledge. These principles should be understood by every programmer. But...

MapReduce: Simple data processing on large cluster

The REST service can help developers to provide services to end users with a simple and unified interface. However, in the application scenario of data analysis, some mature data analysis tools (such as Tableau, Excel, etc.) require the user to provide an ODBC data source, in which case the REST service does not meet the user's need for data usage. This article provides a detailed overview of how to develop a custom ODBC driver based on the existing rest service from an implementation perspective. The article focuses on the introduction of ODBC ...

"Editor's note" Shopify is a provider of online shop solutions company, the number of shops currently serving more than 100,000 (Tesla is also its users). The main frame of the website is Ruby on rails,1700 kernel and 6TB RAM, which can respond to 8,000 user requests per second. In order to expand and manage the business more easily, Shopify began to use Docker and CoreOS technology, Shopify software engineer Graeme Johnson will write a series of articles to share their experience, this article is the department ...

What kind of virtualization technology to choose for the cloud computing platform will be a problem that cloud computing construction will face. This article compares and analyzes the architecture levels of the four mainstream virtualization technologies.