Specsavers sees clear benefits in open source

It has become a commonplace perception that the UK is rather unenlightened when it comes to open-source software.

According to Alfresco's Open Source Barometer, Britain is behind the US, France, Germany, Spain and Italy when it comes to adopting community-developed software, and, whatever its procurement rhetoric, central government seems content to continue entering into IT framework agreements with the likes of Microsoft and Oracle.

Mike Banahan, chief technology officer of OpenForum Europe, once described the UK as a "third-world country" compared with the rest of Europe when it comes to public- and private-sector interest in open-source software.

But some UK companies provide evidence that tells a different side of the story, and one of these is Specsavers Optical Group with its recent deployment of the open-source tools OpenLDAP, Samba and Gosa to handle directory services for its worldwide chain of optician stores.

Anyone looking for real-world, large-scale, business-critical enterprise uses of open source need look no further. Specsavers is one of Britain's fastest-growing retailers and is the largest privately owned chain of optician stores in the world, with more than 1,000 outlets across the UK and Europe, a figure that has doubled over the past four years. Turnover for 2007 exceeded £1bn and the company is still growing fast, with 100 stores about to open in Australia.

The expanding Specsavers has an official corporate policy to use open-source software and open standards by default.

While the Guernsey-headquartered company relies on Windows desktops, it uses open-source software elsewhere in the business, including Scalix, an enterprise email and groupware server that runs on Linux. In-store terminals use an in-house application, Socrates, that runs on embedded Linux, and Specsavers operates Red Hat Enterprise Linux servers alongside Windows and proprietary Unix.

Specsavers group IT director Michel Khan has no fears about the ability of open-source software to handle large-scale, quick-growing corporate systems — quite the reverse, in fact. The low upfront cost of open-source software and lack of licensing complications were important to the directory services deployment, he said.

"The scale of this deployment has been a real challenge in terms of the economics of the investment," Kahn said. "Pursuing an 'open source, open standards' strategy has allowed us to meet that challenge."

Timeline
The process began in June 2006, when Specsavers asked Sirius — a UK-based, open-source services group — to create a centralised model of access control for their UK Windows workstations and network services.

The company was initially using a proprietary LDAP (lightweight directory access protocol) implementation, but Sirius suggested using OpenLDAP instead and Specsavers quickly saw the advantages of going with the open-source alternative.

One of these advantages was scalability: Specsavers had decided to expand the project from the UK to its worldwide business, which was growing rapidly, partly as a result of a number of acquisitions in Europe — a factor that can often present IT integration headaches.

OpenLDAP was initially implemented with Samba networking software and the Gosa graphical management interface running on Red Hat servers, to authenticate Windows PCs and other network services in Guernsey and the mainland UK.

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The deployment was then expanded internationally, with the global OpenLDAP master running in Guernsey, and delegated and replicating OpenLDAP masters in the UK, Finland, Hong Kong and Australia. This modular architecture allows users within one country domain to access network services in other countries using inter-domain trusts.

The global system went up and running at the end of 2007. "The back was broken in the last quarter of last year. It was effectively a three-month project," said Sirius chief executive Mark Taylor.

OpenLDAP, Samba and Gosa
LDAP was originally developed as a way of accessing X.500 directory services over TCP/IP, which is more "lightweight" than the open systems interconnection (OSI) protocol stack required by the X.500 directory access protocol (DAP).

LDAP made its debut in the early 1990s, put together by developers from the University of Michigan, Isode and Performance Systems International, with more recent development handled by the Internet Engineering Task Force (IETF).

It is a firmly established standard, defined in IETF requests for comments (RFCs), and has been implemented in a wide variety of more or less proprietary systems, one of the best known being Microsoft's Active Directory.

OpenLDAP was initiated in 1998 by Kurt Zeilenga, and started as a clone of the reference source code from the University of Michigan. It is released under its own OpenLDAP Public License and...