“We left the meeting with a list of open issues, not a handshake.”
David Sacks.
“Best-of-breed versus single vendor” is an age-old discussion point between OSS exponents.
There is no right answer to this argument, with every customer having different needs. However, when speaking about the best-of-breed model, I sometimes use the handshake analogy to describe why we should aim to limit the number of disparate systems to as few as possible.
The theory equates to the (number of people at a gathering to the number of handshakes required to greet them all) with (the number of systems to interfaces (and associated complexity)).
1 person (system) = nobody else to shake hands with (0 interfaces).
2 people (systems) = 1 handshake (1 interface)
3 people = 3 handshakes
4 people = 6 handshakes
5 people = 10 handshakes
As you’re noticing, one progressively additional system adds an increasing number of additional interface plus associated complexity.
[Yes, I know that not all systems will interface with all other systems in an OSS. Yes, I also know that single vendor solutions will invariably have internal interfaces too. But I’m sure you’ll be prepared to humour me and acknowledge the concept :)]