Hooks in Base Code

Clayton Jones drcjjones at gmail.com
Sat Jul 21 18:28:42 CEST 2007

Hi everybody,
Coming late into this discussion, but if i could put my 2 cents worth
(or whatever that is in euros these days..)...

I like the ideas presented here, but i have some experience designing
& building real time & embedded systems so some points to think about:

1) The Event Router should also have some sort of priority mechanism
to decide who gets the events first, otherwise it's whatever order
shakes out from order of registration + rule evaluation.  For example,
you might not want a bunch of other processes who happen to come first
on the notification list causing the gui to have a large lag time
between notification of incoming call and actual display on the screen
(or playing of ring tone, etc.).  We have to remember this is a phone
first and all other things second - the carrier network won't wait
while we figure out what to do with the call.

2) We have to be careful about race conditions in event notification
latency and order. Two examples:  a) one event causing a process to
generate an event which eventually circulates thru the system and ends
up generating the original event.  b) an event that, simply by
arriving at one process later than another, causes a series of events
or actions that conflict or feed one another causing endless event
generation or system hang.  Much of this is application-dependent, but
the Event Router could have some rules built-in to stop the event
chain if it sees things getting out of hand (e.g. the same event
generated 500 times in a second).

3) Finally, we have to keep in mind that this is a small-form factor,
battery-powered system - we'll always be behind on the power/resource
curve from our desktops, so we have to be aware of speed and
resources.  One of the things that absolutely drives me up a wall
about my Motorola Razr is the lag time between pressing keys and
seeing a response - especially in my address book or when pressing
"answer" for incoming call.  This frustration is one of the reasons i
can't wait to get my hands on a Neo  so i can make the phone behave
the way i want!  Also, FWIW, some friends of mine who've played with
an iPhone report that Apple seems to have paid attention to this as
well - they say they're impressed with how responsive the phone is.

Hopefully this all isn't so obvious that i get flamed for wasting
everyone's time....


On 7/21/07, Jim McDonald <Jim at devzero.net> wrote:
> Hans L wrote:
> > Hey folks,
> >
> > Great discussion going on here.  I've been putting a lot of thought
> > into the issue too, so I  figured I'd add my two cents.
> [...]
> Yep this is very similar to what I'm thinking of.  Given that we're all
> pretty close to what we think we need it's probably time to put
> something on the Wiki.  I've put an initial page at
> http://wiki.openmoko.org/wiki/Wishlist:Extension_Framework so if people
> can make any additions that they wish there it would be easier to track
> and get us to the stage where we can get the buy-in of the openmoko team
> and start laying down some code.
> There are a few things that you mentioned here that I haven't yet
> covered in the Wiki such as profiles, use of the configuration GUI and
> the like so if you want to flesh them out on that page it would be much
> appreciated.
> Cheers,
> Jim.
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