Re: [NTLK] [ANN] ATA Support 1.0RC6

From: Paul Guyot (pguyot_at_kallisys.net)
Date: Thu Oct 16 2003 - 21:13:46 PDT


Aux environs du 17/10/03 à 13:00 +1300, sous le titre "Re: [NTLK]
[ANN] ATA Support 1.0RC6", Tony Kan prit sa plus belle plume pour
écrire les mots suivants:
>This ATA support project has got to rank as one of the Newton developments
>which has brought a huge amount of confidence for Newton users that the
>platform will continue to be relevant as the technology environment
>involves. From my reading of the archives, not only have you conquered the
>heights of technical complexity in producing this solution but also made the
>product accessible to nontechnical types like myself by making it easy to
>install. Go you good thing!

Thanks. Actually my nightmare is users losing data (a lot of people
say that one of the great strength of the Newton is that they never
lost data). Hence the time spent on making sure the transaction
engine is as bug-free as possible. The new test suite is really
violent, it makes 20,000 random operations on the store and checks
what ATA Support does with what it is supposed to do. Previous tests
were pretty nice, I just performed regular operations on the store
like mimicing a package installation. I fixed four bugs in a row with
this and the only test I don't do yet is the power-plug test (check
that if you remove the batteries at any time, your data will be safe,
it should be).

>I am glad that you intend to include backup facilities in your version 1.0
>release.

In fact, most of it was coded. I just don't want to release something
unfinished concerning backups.

>What are the benefits of FAT support and an asynchronous driver?

You're right, I should have explained.

FAT Support means you'll be able to exchange files with cameras and
laptop computers through the ATA card. As in, you take your camera,
you shoot a picture, you insert the CF card in an adapter and the
thing in your Newton, and then you can e-mail the picture or view it.
Or you make a backup to a FAT partition and you insert the card to
your laptop and you can just copy the file somewhere on your laptop's
hard drive to have it safe (or burn it to a CD or whatever).

Asynchronous driver comes from the comparison of the following facts:
- The NewtonOS system doesn't really care when I actually write data
to the card. In fact, since it's a transactional persistent object
store, I don't have to write data until the transaction finishes
(since if the batteries are removed or the transaction was aborted,
anything that was written should be cleared, to simplify).
- the driver spends most of its time waiting for the card to do the things.

With a synchronous driver, the system in the end waits for the
driver. It has to for read operations (I cannot invent what is to be
read), but it hasn't with write operations (as long as they're
performed before I tell the system the transaction was finished with
no error). So I could intermix read and write operations to do reads
as soon as possible and write whenever I have the time to write on
the card. The whole thing would not block the system which would be
capable instead of say, reading from another card in case you're
moving something to the ATA card, listening on the network, etc.

In a nutshell, the question is: exchange files with cameras and
laptops or increase speed significantly.

Both changes are planned. The question is: what shall I do first?

Paul

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