[DAS2] DAS intro

[Steve Chervitz]

Ed Erwin wrote: 
> Andrew Dalke wrote:
>> The front of the DAS doc starts
>> 
>>   DAS 2.0 is designed to address the shortcomings of DAS 1.0, including:
>> 
>> That kinda assumes people know what DAS 1.0 is to understand DAS 2.0.
>> 
>> How about this instead, as an overview/introduction.
>> 
>>  ======
>> 
>> DAS/2 describes a data model for genome annotations.
> 
> In general I like this better than the original introduction.  Thanks
> for writing it.
> 
> But I agree with Andreas that the first line is better as:
> 
>> DAS/2  is a protocol to share biological data.
> 
> I definitely think of DAS as a protocol first, rather than a data model
> first.

I concur. The main aim of DAS is to define an API to allow clients to query
servers in order to retrieve bioinformatics data objects in defined response
formats. Of course, the writeback facility of DAS/2 will make DAS more of a
two-way street so we could say 'sharing and editing', but I think retrieval
is more fundamental and probably accounts for the majority of uses.

How about this for the first line:

  DAS is a protocol for sharing biological data.

No need to limit it to version 2. This applies to all versions. Use 'DAS/2'
when talking about new features in this version, such as writeback.

Steve