Understanding and Replacing Microsoft Exchange
Linux by itself provides a formidable set of internet applications for mainframes, which have always needed them. IBM's eServer strategy seemed incomplete without a robust set of internet tools, which it promised to provide to all of its brands. Near the end of calendar year 2000, IBM demonstrated it could host a thousand instances of Linux on a single S/390 mainframe.
Even so, IBM realized that web servers and GNU applications didn't provide a complete value proposition. IBM needed an application that made Linux a host that reached further into mainstream computing. So they made a call on us.
In April 2001, when the sales manager for IBM's zSeries, the new name for the S/390, visited our company, Bynari, Inc., I did not understand his interest. After his visit, I understood it perfectly. Bynari, Inc. became IBM's first Linux Influencer Partner.
Initially, people knew us for making Linux and UNIX clients talk to Microsoft Exchange servers. Looking to broaden our market, I found the “Exchange Replacement HOWTO” by Johnson and Mead (www.bynari.net/whitepapers_howto.html). Using their work as a guide, we built a server for our Linux client and Microsoft Outlook. Our server and its Outlook Configuration Guide caught on with the reseller channel.
We didn't know anyone at IBM when we ported our server code to a Linux instance running on an S/390 Multiprise 3000. Jimmy Lee, then with Equant, provided the resources to see if we could do it. Gary Ernst of Equant configured the S/390 instance of Linux and provided assistance in getting our server to work.
As long as Microsoft Outlook had an Internet Mail Only mode and provided peer-to-peer folder sharing, we had a product that allowed UNIX and Outlook clients to schedule meetings and delegate calendar tasks. Our server scaled nicely, and we mimicked the Exchange global address list (GAL) while providing views of users' free/busy time and a decent administrative interface.
But then Microsoft released Office XP and made major changes in Outlook. Suddenly, our products needed server-side calendaring. We feared the growing appetite of IBM enterprise customers for a low-cost server solution for Outlook might wane. Therefore, we needed peer-to-peer calendar sharing in Outlook's Internet Mail Only mode, or we needed something on the server side.
With the January 2001 LinuxWorld Conference & Expo approaching, IBM continued marketing our server, somewhat blind to the needs of Outlook XP users. I knew we had to do something and do it fast or lose IBM's trust. At that time, the person who best understood the market problem was Roger Luca of Mainline Information Systems.
Fortunately, Roger and I developed a good working relationship. With Roger at the head of sales and marketing, Mainline became the largest reseller of IBM mainframes. They also were our biggest supporter outside IBM. Roger provided us with hardware resources to help us build server-side calendaring into our product, as well as with people to support us if we ran into hardware-related problems.
Imagine having completed an exhaustive year of development. You have trips scheduled for the holidays and other plans. Then you get a call on your cell phone; your boss asks you to attend an important meeting. That's what happened in our shop. I could hear the dread in the developers' voices when they answered my call.
We met on November 7, 2001, to see if we could deliver a server-side calendar solution by Christmas. Mainline had several sales pending, and they needed that functionality. Two of my people agreed to work with me to get the solution.
As the senior developer, I provided the project framework. In theory, a project has a variety of phases and processes. To shorten the project's life, I instituted a three-step approach that called for research, invention and execution. I gave each phase a milestone. So instead of starting with code, we started browsing the Internet and any books we could find.
Following a week of intensive research, we discovered our challenges. We had to figure out how Microsoft's DCE-RFC protocol stored and moved calendar events around. We had to interpret the stored data, provide a format that we could store on an IMAP server and then forward the data to an Outlook client in its familiar schema. We also had to provide access control over those information stores to allow a user to appoint and delegate control over his or her calendar to other users with varying permission levels.
We spent another intense week researching and discovered a consensus. Every expert, newsgroup, Outlook specialist and company that tried said one could not create a Microsoft Outlook calendar store on an IMAP server. Here's how we did it.
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