Computing appliances are gaining a foothold in enterprise IT systems because of their simplicity, reliability, ease of use and lower cost compared with general purpose computers.
The appliance is basically a self-contained IT system that can be plugged into an existing IT infrastructure to carry out a single purpose, making it comparable to a consumer appliance such as the toaster.
The appliance is designed to address a specific IT operation from within a closed architecture that may contain an operating environment, storage and specific applications. The appliance's purpose could be to provide additional processing power, network storage or monitoring, or anti-virus and security.
As a concept, the computing appliance is not new in fact, home users were the early adopters of many appliances with such things as games consoles, the iPod, or TV set-top boxes.
Among businesses, appliances have largely been adopted to carry out networking functions. For example, special-purpose router appliances from suppliers such as Cisco and Nortel have almost entirely replaced general purpose computers for packet routing.
Other examples of network appliances include network fax servers and network back-up servers. The modern printer can be viewed as a network appliance, plugging into the network rather than into a general-purpose computer.
Appliances have also become popular for network storage, with firms like Network Appliance (NetApp) producing the Windows or Unix-based network storage appliance, formerly referred to as a filer.
There are now signs that the appliance is ready to evolve as software firms such as SAP, Oracle and Microsoft are starting to show interest in them.
John Enck, a vice-president and research director at analyst firm Gartner, said that this year, "IT managers should expect to be deluged with a new wave of server appliances offering everything from simple single-function operations - for example, file servers, Java Virtual Machine processing and so on - to completely integrated applications, operating systems and hardware systems."
According to Enck, after an unsuccessful run in the early 2000s, application and hardware suppliers are now returning to the appliance model for financial reasons. Software suppliers are eyeing the hardware revenues, and hardware suppliers are looking to gain some application and operating system revenues.
Gartner's main advice to users evaluating appliances is to ensure that the devices integrate into their current management systems. Second, users should ensure that the upfront cost savings of an appliance model offset the ongoing, often higher administration costs of the appliance.
Despite these management issues, many users across the sectors have some experience of appliances.
One of the most popular appliances is the remote access security appliance, which provides secure virtual private network (VPN) browser-based access to applications and data from any remote computer, encrypting traffic at both ends so it remains secure.
Virgin Atlantic, the Labour Party, Birmingham City Council, games manufacturer Hasbro and utility firm EDF Energy are among those using VPN appliances.
According to a Forrester Research report on enterprise gateway security appliances, the main suppliers of virtual private network appliances based on Secure Sockets Layer (SSL) data encryption technology are Juniper Networks, Aventail and Citrix Systems.
Robert Whiteley, a senior analyst at Forrester, said, "Juniper Networks maintains its SSL VPN leadership thanks to its superior reverse proxy technology (which only allows access to specific corporate applications and data) and focus on secure mobility.
"Aventail trails close behind with its fully integrated end-point security and similar strength in mobile device access. Citrix Systems and Microsoft also provide leading technology that focuses on access and acceleration for corporate applications."
Microsoft entered the SSL VPN system market last year when it acquired Whale Communications, the developer of the popular e-Gap SSL VPN appliance.
Caymas Systems is another supplier of SSL VPN appliances. Caymas Systems has an innovative approach that combines remote and local network access control in a single appliance, an approach also taken F5 Networks, Cisco and Nortel. Cisco and Nortel combine two secure VPN technologies - IP security and SSL - in a single appliance.
Enterprise gateway security appliances can be used to authenticate users in combination with two-factor authentication tokens such as RSA Security's SecurID, which provides one-time passwords to remote workers.
Another popular type of appliance are those that plug into the network and monitor all network traffic to ensure it remains secure.
Arcadia Group implemented a network monitor in May this year. Arcadia is one of the largest clothing retailers in the UK, with more than 25,000 employees and over 3,000 staff using the IT system.
Arcadia installed Secure Computing's Webwasher enterprise gateway appliance to protect employee and customer data from being inappropriately accessed or transferred, and also to help enforce its internet access policies.
These policies include blocking inappropriate material, regardless of whether it is encrypted via SSL. Webwasher is one of the few security appliance products that can scan encrypted SSL traffic.
The choice of anti-virus and anti-spam appliances is also growing as security suppliers including Trend Micro and Finjan develop hardware appliance versions of their software products.
Earlier this year, global consumer packaging group Rexam piloted Trend Micro's new Interscan Messaging Security Appliance (IMSA).
Rexam had been using Trend Micro's Scanmail and Interscan Messaging Security Suite software products to protect its 8,000 users around the world. However, the firm opted to trial IMSA because it was simpler to deploy, supported a high throughput of data traffic and had hardware redundancy to ensure it worked around the clock.
Antonio Traetto, global messaging manager at Rexam, said that the trial went well, and that adopting the appliance meant the firm could continue its Linux strategy.
"We are looking at switching from a Windows-based system to Linux, and IMSA runs on Linux too. Our objective is to make internal support and management easier, so if the hardware and software come from Trend Micro it will save doubling up on support and also warranty costs," said Traetto.
Another class of server appliance that is gaining in popularity is the network attached processing (Nap) or "compute" appliance, which can offload computing operations onto a dedicated box.
Azul is one such Nap appliance supplier, and released the first box, the Vega 1 compute appliance, in 2005, specifically designed to help with Java application performance.
Last year, Azul issued the more powerful Vega 2 device, boosting the processor and memory specification from 24 core processors with 96Gbytes of Ram, to 48 cores. The latest Vega 2 appliances will feature multi-way processor systems with a total of 768 core processors, supported by 768Gbytes of Ram.
"The proposition that Azul's device offers is to transparently offload applications from the Java Application Server to the compute appliance, where multiple processor cores and large memories are at the disposal of the application, all managed by the Azul Virtual Machine with no change to the original applications," said Michael Azoff, a senior research analyst at Butler Group.
"An important endorsement of compute appliances is Azul's recent deal with BT, which has allowed the telecoms company to reduce datacentre costs for its gateway infrastructure, helping to meet a massive growth in business with cost-effective systems. Reductions in power consumption and cooling requirements are also a factor in the savings."
It is clear that network, storage, computing, security and other types of appliances are fast becoming part of the IT infrastructure.
However, Enck offers a warning to users. "Although the appliances are certainly more attractive in this new wave of offerings, they still pose the problem that was a barrier to the first wave: non-integrated management. Simply put, these appliances will contain their own administrative and management interfaces that may or may not tie into broader datacentre management tools.
"As attractive as these appliances may seem, IT managers must assess the impact they have on existing datacentre management systems. By 2010, lack of integrated management features will limit single-function workload appliances (carrying out database management, data warehousing, Java execution, file serving and SSL encryption) to tactical deployments of less than 10% penetration in the datacentre."
By adopting more and more single-function appliances, could we, as Gartner warns, be storing up serious IT management issues for the future? If we are, we had better be ready for another wave of hardware consolidation further down the line.