Microsoft's Adrian Lannin, lead program manager in charge of "making printers, scanners and faxes work in Windows", wrote a detailed post on the "Building Windows 8 blog" detailing how the software giant is simplyfing printing in Windows 8. Lannin points to the fact that Microsoft has had to introduce a new printer driver architecture called V4 to address some challenges that Windows RT, which is essentially Windows 8 on ARM, has introduced.
A radically new hardware architecture plus the requirement to work on limited resources (both in terms of raw power and memory) means that Microsoft has had to re-engineer a few things in order not to "negatively impact ARM systems by running unnecessary services". This means, for example, that Windows 8 will ship with a core set of so-called in-box drivers that support "popular" devices with users being able to download additional drivers if needed from Windows Update.
Microsoft managed to do this by building an extensible print class driver framework that negates the need to ship hundreds of printer drivers with the OS. This means that the disk space needed for drivers to support printers and imaging devices in Windows 8 is less than a quarter of what Windows Vista needed and less than half of Windows 7's requirements.
And perhaps the most visible difference between the old printing experience and the new one will be the fact that the UI portion of the driver will be an app, a separate component rather than being part of the driver.
Source : Microsoft