AlphaMail Is Scalable and Accessible Web Mail
AlphaMail is a high-performance, feature-rich, open-source Web mail system created at the University of Oregon. The interface includes message snippets in indexes, UTF8 composition and numerous viewers for attachments (such as image icon preview and file listings from tarballs). It also tries to strike a balance between desirable features and too much interface noise. It was created to address several problems that exist with other open-source and commercial Web mail systems.
The first concern AlphaMail addresses is performance. Almost all Web mail systems (such as Horde's IMP Web mail Client and SquirrelMail) use IMAP from within the Web server, which is incapable of persisting an IMAP session.
The IMAP protocol is designed to optimize access through persistent access, so this is an inherent and recognized problem. The problem is usually mitigated with an IMAP proxy that maintains a persistent connection. The problems with this solution are multifaceted.
One problem is that the code in the Web mail client itself cannot depend on the state of the IMAP connection and must repeat commands as if each mouse click were a new IMAP session. This is a problem, because the sequence of required events for a new session in the IMAP protocol include authenticating and selecting the desired folder. The benchmarks of several IMAP servers indicate that the repetition of the folder selection command, even if the folder is already authenticated and selected (that is, through a proxy), can cause significant extra server load.
These inefficiencies could be addressed through improvements in the IMAP server and proxy algorithms, but another problem is intractable: a proxy cannot improve the protocol. The fact that the Web mail client is using IMAP forces it to behave as a complete standalone client. If the developers want to add a complex feature, such as conversation views (à la Google mail), which requires complex message cross-referencing across several folders, the protocol itself becomes a major impediment.
AlphaMail solves these problems by including a middleware layer that uses a simplified and extensible protocol for the Web application and is responsible for optimizing access to the mail servers. The protocol supports highly specialized commands that allow the Web code to ask for the information needed for a page directly, without having to make any assumptions about the state of the IMAP connection.
This has the additional advantage that the IMAP protocol handling in the middleware layer can be written in a high-performance language (in this case C++), can cache results and can optimize the interaction. The middleware program is known as the imap_webcache, because it caches both data and network connections for the mail interaction.
AlphaMail supports GNU autoconf and has been built cleanly on many Linux variants, FreeBSD, Solaris and Darwin (OS X). The easiest platform to install is Fedora Core 5 via yum(1), as described on the AlphaMail home page.
I highly recommend using Fedora Core 5 on a test machine to avoid the headaches of dependency resolution for your initial trial run. The actual build is pretty much what you'd expect, but solving runtime dependencies can be challenging.
If you decide on a source build, first you need to install the Boost C++ libraries (see Resources).
You need the Boost Jam utility (usually named bjam) as well as version 1.33 or better of the Boost C++ libraries. Jam is sort of a combination between GNU autoconf and make. Follow the instructions from the Boost Web site for details, but essentially, extract the files and run:
# bjam install
In rare circumstances, you may want to pass options (such as an installation prefix). See the Getting Started guide on the Boost Web site if you have special needs.
Practical Task Scheduling Deployment
July 20, 2016 12:00 pm CDT
One of the best things about the UNIX environment (aside from being stable and efficient) is the vast array of software tools available to help you do your job. Traditionally, a UNIX tool does only one thing, but does that one thing very well. For example, grep is very easy to use and can search vast amounts of data quickly. The find tool can find a particular file or files based on all kinds of criteria. It's pretty easy to string these tools together to build even more powerful tools, such as a tool that finds all of the .log files in the /home directory and searches each one for a particular entry. This erector-set mentality allows UNIX system administrators to seem to always have the right tool for the job.
Cron traditionally has been considered another such a tool for job scheduling, but is it enough? This webinar considers that very question. The first part builds on a previous Geek Guide, Beyond Cron, and briefly describes how to know when it might be time to consider upgrading your job scheduling infrastructure. The second part presents an actual planning and implementation framework.
Join Linux Journal's Mike Diehl and Pat Cameron of Help Systems.
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With all the industry talk about the benefits of Linux on Power and all the performance advantages offered by its open architecture, you may be considering a move in that direction. If you are thinking about analytics, big data and cloud computing, you would be right to evaluate Power. The idea of using commodity x86 hardware and replacing it every three years is an outdated cost model. It doesn’t consider the total cost of ownership, and it doesn’t consider the advantage of real processing power, high-availability and multithreading like a demon.
This ebook takes a look at some of the practical applications of the Linux on Power platform and ways you might bring all the performance power of this open architecture to bear for your organization. There are no smoke and mirrors here—just hard, cold, empirical evidence provided by independent sources. I also consider some innovative ways Linux on Power will be used in the future.Get the Guide