Why not use the multi-layer image style

[HuKeping]

Hi there,

As the spec says , the image layout of ACI is straightforward, but why we don't use the multi-layer-style as the OCI image(or just docker image for now) defines?

Personally I prefer the former one, but wonder if there's some special consideration about this.

Sorry if I missed anything.

[jonboulle]

appc images support effectively the same thing (although it's a DAG rather than a simple chain) via dependencies - the process for assembling the filesystem is described here: https://github.com/appc/spec/blob/master/spec/ace.md#filesystem-setup