[Tinyos Core WG] storage

[David Gay]

On 9/18/06, Jonathan Hui <jhui at archrock.com> wrote:
>
> Philip Levis wrote:
> > But you can mask these latencies. For example, rather than erase a block
> > when you reach it, you can erase it when you reach the previous block.
> > As it is now, it's very difficult to write a high-speed logger with a
> > circular log. There's little sense of how long the erase will take, and
> > therefore how much buffering you'd have to do.
>
> It's not obvious to me how you can mask these latencies. Whether you do
> it on the previous block or not, the flash chip will be busy for order
> seconds.

In case it wasn't clear to Phil: the flash chip can't erase one block
and write elsewhere at the same time.

> If your period between writes is a fraction of a second, then
> buffering has to happen somewhere, and how large that buffer should be
> is best left to the application to decide.

The HighFrequencySampling from 1.x used a "BufferedLog" component with
the same API as logging. I'll agree w/ Jonathan and claim that's the
right approach ;-) Should the TEP mention/include such components? For
logging only?

David