 |
||||
|
|
|
||
|
Contents 
Introduction
A changing market
The appliance-making appliance
Do they really scale?
The ease-of-use myth
Walking the appliance road
Taking a holiday from spam
What about the disks? |
|
||
|
|
||||
|
|
||||
While appliance vendors' arguments are very similar, their products increasingly fall into two camps. "A couple of years ago an appliance was a black box," says Gartner's Asia-Pacific research director for servers and storage Phil Sargeant. "It was almost a magical thing."
Black boxes, or "pure" appliances, are still favoured by many vendors. Designed from the ground up for a particular computing task, pure appliances generally have a custom motherboard holding all components, and no moving parts other than fans and a sealed box. Software is often embedded in application specific integrated circuits (ASICs) and/or field programmable gate arrays to allow easier updates.
Of course, custom hardware development of this variety is expensive, and while appliances are a booming market they ship in nowhere near the volumes achieved by personal computers and PC-servers. Real-time operating systems are also expensive and eclectic. Yet demand for appliances is strong. Some vendors, therefore, see "hybrid" appliances.
"Now the lines have blurred between an appliance and a server," Gartner's Sargeant says. "An appliance is really just a server that does one thing." This definition is reflected in the fact that many hybrids use commodity PC or server technologies as a way into the market.
Hybrid appliances are hardened by removing certain hardware elements or using them in configurations that disable known risks. Hybrid appliances also lock down their operating systems, usually by using customised versions of Linux or Microsoft's little known program to enable "Windows Powered Specialized Servers" that uses a special cut of Windows Server 2003. Some hybrids even revert to storing the operating system on a hard disk, despite the risk of mechanical failure.
