Hotwired 3 TDIG Breakout

[John Swinbank]

Hi Roy,

On 16 Nov 2013, at 11:46 , Roy Williams <roy at caltech.edu> wrote:
> On 11/15/13 5:29 PM, John Swinbank wrote:
>> - Mike introduced his proposal for a “VOEventContainer”: essentially
>> a means of bundling multiple VOEvents together with supporting data
>> such as images into a single entity. This could address both issues
>> surrounding bulk transport as well as the stated aim of the LSST
>> folks to include cut-out images with their events. The proposal
>> received a positive response from the audience, but there was some
>> quibbling over technical details. Mike will introduce his proposal
>> and kick off a discussion as to its implementation on the mailing
>> list.
> 
> I heard the opposite of this. My impression was that there was a rejection of the idea of inventing a special IVOA format for bundling content. I heard a consensus that *zip* is a perfectly good way to bundle multiple events, to bundle events with binary content such as images. That zip is well known, widely implemented, and trusted. It is the solution used in similar cases, such as epub and docx format, where an XML document is bundled with images. Try it yourself:
> 	cp document.docx document.zip
> 	unzip document.zip
> What I heard is that this is a solved problem, and there is no need to invent anything new for bundling XML files and their images.

My recollection is that we were rather sceptical of the initial proposal of embedding images etc as Base64 encoded data in a massive XML document; rather, as you say, the problem of how to store and bundle binary data has already been solved by zip (or tar, etc). However, there was still a feeling that some structure within the container was needed, so that, for example, a VOEventContainer might take the form of a zip file together with an XML-based manifest describing its contents.

Cheers,

John