Andrew Lunn <andrew@lunn.ch> writes:
There has been comments that Rutgers code has too many layers. Rutger
aims to allow as much code reuse between drivers as possible, which i
think is good. Simon commented that he thinks Ross's design may result
in a lot of code stuck in HALs where it is hard to reuse without copy
paste. However Ross argued that he thinks that making code reusable is
going to be hard, there is too many different configurations of chips
and controllers, etc.
With only one supported platform on Ross's code and two with Rutgers,
i think it is too early to tell the truth. However, im generally in
favour of layers.
Just a few quick words about layering...
We have to be very careful in eCos not to over-do the abstractions.
eCos is still an embedded operating system and not a full-featured
general purpose OS. As such we must take care not to compromise code
size and performance. There are some areas in eCos already where we
have more layers than we strictly need, and performance has
suffered. Many of the target processors are relatively slow, without
caches or much fast memory and every extra call and indirection can
cost a lot of cycles.