Complex sentence: The Linux kernel's architecture was required to support a large number of independent volunteer developers, which suggested that the system portions that require the most developmentthe hardware device drivers and the file and network protocolsbe implemented in an extensible fashion.
Split into simpler sentences: The Linux kernel's architecture was required to support a large number of independent volunteer developers. This requirement suggested that the system portions that require the most development--the hardware device drivers and the file and network protocols--be implemented in an extensible fashion.