Which are the consistency models used for distributed systems? Papers that survey the consistency models Robert C. Steinke and Gary J. Nutt. 2004. A unified theory of shared memory consistency. J. ACM 51, 5 (September 2004), 800-849. DOI=10.1145/1017460.1017464 http://doi.acm.org/10.1145/1017460.1017464 David Mosberger. 1993. Memory consistency models. SIGOPS Oper. Syst. Rev. 27, 1 (January 1993), 18-26. DOI=10.1145/160551.160553…
What are the popular / good NoSQL databases nowadays? MongoDB, CouchDB Find more at https://en.wikipedia.org/wiki/NoSQL and http://nosql-database.org/ Answered by omshivaprakash.
What are the SQL layer solution over NoSQL databases such as key/value stores? Phoenix: A SQL layer on HBase: https://github.com/forcedotcom/phoenix They also show some performance results: https://github.com/forcedotcom/phoenix/wiki/Performance F1 – The Fault-Tolerant Distributed RDBMS Supporting Google’s Ad Business: http://research.google.com/pubs/pub38125.html With F1, we have built a novel hybrid system that combines the scalability, fault tolerance, transparent sharding,…
I got a message: Package subcaption Error: `caption’ package not loaded I guess that I should install the cpaton package. How to install the caption latex package on Fedora? Fedora 19 is already shipped with the latex Tex Live 2013. You can directly install it by yum. # yum install texlive-caption For older Fedora releases,…
Any free server images? 24 Free Data Center Photos from fatcow.com 24 Free Data Center Photos: http://www.fatcow.com/data-center-photos From Wikimedia commons: Multiple servers: http://commons.wikimedia.org/wiki/File:Server-multiple.svg Server: http://commons.wikimedia.org/wiki/File:Server.svg Yellow server: http://commons.wikimedia.org/wiki/File:Server-yellow.svg Green server: http://commons.wikimedia.org/wiki/File:Server-green.svg More from clker.com: Web Virtualization Server clip art: http://www.clker.com/clipart-1826.html Small Case Web Mail Server clip art: http://www.clker.com/clipart-1902.html Inside our data centers from Google —…
What is the x86-64 calling convention by gcc? The calling convention of the System V AMD64 ABI is followed on GNU/Linux. The registers RDI, RSI, RDX, RCX, R8, and R9 are used for integer and memory address arguments and XMM0, XMM1, XMM2, XMM3, XMM4, XMM5, XMM6 and XMM7 are used for floating point arguments. For…
As a WordPress user, you may have noticed that the default HTML editor lacks some of the features that you need for your content. Fortunately, you can add custom buttons to the WordPress HTML editor to make your content creation experience more efficient and productive. In this post, we will explore how to add custom…
How to disable automatic comment insertion in Vim? Add to ~/.vimrc: au FileType c,cpp setlocal comments-=:// comments+=f:// More: http://vim.wikia.com/wiki/Disable_automatic_comment_insertion
Evolution is a great personal information management tool that provides Email, address book and calendar tools. Evolution provides many enterprise friendly feature such as native support to Microsoft Exchange connectivity for Emails, address books and calendars. Evolution uses various ways including plain files and dconf configuration systems. This post will give an introduction to the…
The encoding of x86 and x86-64 instructions is well documented in Intel or AMD’s manuals. However, they are not quite easy for beginners to start with to learn encoding of the x86-64 instructions. In this post, I will give a list of useful manuals for understanding and studying the x86-64 instruction encoding, a brief introduction…
The USB standards have evolved to 3.1 and the supported throughput have been increased too. On Linux, the support to USB standards are following the standards development. In this post, we will survey the standards that common hardware support and the support in Linux. USB standards USB 2.0: https://en.wikipedia.org/wiki/USB#USB_2.0 Speed: <= 60MB/s, or 480 Mbps…
Abstract In systems, sometimes, we use one global lock to keep synchronization among different threads. This principle also happens in QEMU/KVM (http://wiki.qemu.org/Main_Page) system. However, this may cause lock contention problem. The performance/scalability of whole system will be decreased. In order to solve this problem in QEMU/KVM, x-data-plane feature is designed/implemented, which the high-level idea is…
CentOS is a super solid Linux distro. However, its default repository’s packages are limited compared to Fedora. Even Fedora needs some additional repositories to have software packages for daily usage, such as MPlayer, ffmpeg. Fortunately, some community maintained repositories provides these software. In this post, we introduce theses additional common repositories and how to install…
It is common practice to calculate the checksums for files to check its integrity. For large files, the checksum computation is slow. Now I am wondering why it is so slow and whether choosing another tool will be better. In this post, I try three common tools md5sum, sha1sum and crc32 to compute checksums on…
Controlling the mounting of filesystems is a useful technique for managing Linux systems. The mounting configurations are mostly in the /etc/fstab file. In this post, we will discuss 2 common and useful techniques for controlling the filesystem mounting by playing with the /etc/fstab file: allowing non-root users to mount/unmount filesystems and avoiding mounting failures blocking…
You may already well know “Linux” and may also use the “operating system based on the Linux kernel” directly or indirectly (you are indirectly using it now as this site is hosted on Linux). But how should we name the OS based on Linux? You may know there is GNU/Linux naming controversy. Different people have…
Ctrl keys are important and possibly most frequently used in Emacs. However, it is painful on today’s common PC keyboards since Ctrl keys are usually in the corner of the keyboard main area. Why the key mappings in Emacs are designed like this? After it was designed, Emacs was commonly on the Lisp Machine keyboards…
Update on Oct. 9, 2014: You should be aware of the possible security problems of blowfish and it is suggested not to be used. Instead, you may consider ChaCha20 as suggested by Tony Arcieri. To use this with OpenSSH, you need to specify the Ciphers in your .ssh/config files as chacha20-poly1305@openssh.com possibly with another default…
UDP has its advantages over TCP, such as being relatively lightweight and receiving one packet per read call (recvmsg), although the programmers need to handle related issues, such as packet lost and out-of-order packets delivery. This post gives information and references on how to write UDP programs in a C/Linux environment. What is UDP Check…
It is quite common to measure the time in programs using APIs like clock() and gettimeofday(). We may also want to measure the time “accurately” for certain purposes, such as measuring a small piece of code’s execution time for performance analysis, or measuring the time in time-sensitive game software. It is hard to measure the…