Each picture is a graph with a list of system calls (syscalls). "In computing, a system call is the mechanism used by an application program to request service from the operating system.". In other words, it will involve the execution of highly privileged code, typically residing in an interrupt service routine.
For the security minded people, this provides a point of vulnerability for malware to exploit. During a syscall, operation is transfered from the application to system. So, if control can be transfered to corrupted code, the malware can exploit it to escalate privileges and wreak havoc on the computer system.
For the regular people, each time a syscall is performed, the software will need to do some housekeeping before transfering control over to another code. More housekeeping needs to be done before transfering control back to the original code. All these extra housekeeping is essentially a waste of computing resource as the main task is not being performed.
Each graph represents the syscalls made by the leading webserver to each operating system (ie, Windows + IIS and Linux + Apache). On both graphs, each syscall routine is represented by a node in the graph. Each connector represents the caller/callee relationship between the routines. I won't give you any prize for correctly guessing which graph represented which OS.
Now, if we take this as a sample representation of the kind of coding practice/style used for the rest of the applications and OS, we come to a very sad conclusion. There are no more gifted people working inside Microsoft. Gifted people do not design software that looks like a friggin' spiderweb. Gifted programmers KISS!
"Any intelligent fool can make things bigger and more complex... It takes a touch of genius and a lot of courage to move in the opposite direction." --- Albert Einstein. So, do not trust your most important tool in life to a bunch of intelligent fools. Vista has been getting nothing but bad press for the last few weeks. Friends, it's time to embrace change!