"The other thing is that we can define and control our own upgrade path. We're not driven by things that have deadlines against them. We can stretch our assets better and we don't have to change our hardware as often.
"Integration and development tools are open source toolsets too, which has allowed us to bring down our development costs as well."
With rapid expansion of both high-street stores and infrastructure on the cards, support for open source moved up a gear in June 2007, when Specsavers migrated its in-store applications from Windows 2000 to Red Hat Linux.
The company had already asked open source services group Sirius to create a centralised access control model for their UK workstations and network services. Sirius proposed using the OpenLDAP directory, which was implemented with Samba networking software and the Gosa graphical management interface.
The final piece of the jigsaw was the Scalix enterprise email system, an open source competitor to Microsoft Exchange Server, which replaced the incumbent SunOne email system.
Khan admits that open source systems may not suit every enterprise, but encourages fellow IT directors to at least consider the options.
"I don't know if it suits everyone, but I would encourage people to look at it closely," he says. "There's a fear factor from the connotation that open source is a free-for-all and you don't know what you're getting, but if you examine it closely you are in a relatively tightly controlled environment that's not very different to a typical licence-fee environment. It's managed, it's supported and it's release-controlled. The real difference is the cost base.
"Most people would find some aspects of open source that would be relevant, and I'd say that a lot of applications will ultimately have open source components as that gives firms a level of flexibility and development capability that they cannot sustain in-house. Otherwise you end up with thousands of developers and a legacy environment that's difficult to migrate."
Following the in-store Red Hat roll-out, Khan admits he finds it irresistible to compare other retail systems with his own.