Regarding operating system structures, which of the following statements is NOT true? $($Chapter $1)$

The exokernel architecture is designed to separate resource protection from management to facilitate application$-$specific customization

A microkernel architecture is called a plugin architecture because of the way capabilities and functionality are added to a minimal core OS

The client$-$server model works over a network. All the machines in this model must have the same operating system

The layered architecture style is one of the most common architectural styles