Add "liftoff" content.

 - Add a tentative agenda for the first meeting, though it isn't yet scheduled.
 - Create an intial directory structure with a few documents.

Charter.md

@@ -0,0 +1,55 @@
+# WebAssembly System Interface Subgroup Charter
+
+The System Interface Subgroup is a sub-organization of the
+[WebAssembly Community Group](https://www.w3.org/community/webassembly/) of the W3C.
+As such, it is intended that its charter align with that of the CG. In particular, 
+the sections of the [CG charter](https://webassembly.github.io/cg-charter/) relating to
+[Community and Business Group Process](https://webassembly.github.io/cg-charter/#process),
+[Contribution Mechanics](https://webassembly.github.io/cg-charter/#contrib),
+[Transparency](https://webassembly.github.io/cg-charter/#transparency), and
+[Decision Process](https://webassembly.github.io/cg-charter/#decision) also apply to the Subgroup.
+
+## Goals
+
+The mission of this sugbroup is to provide a forum for pre-standardization
+collaboration on a system interface API for WebAssembly programs.
+
+## Scope
+
+The Subgroup will consider topics related to system interface APIs, including:
+
+- APIs for host filesystems, network stacks, and other resources.
+- APIs for graphics, audio, input devices
+- APIs for encryption, format conversion, and other transformations
+  (particularly where hardware accelleration may be available on some plaforms)
+
+
+## Deliverables
+
+### Specifications
+The Subgroup may produce several kinds of specification-related work output:
+- Creation of new specifications in standards bodies or working
+groups (e.g. Wasm WG or TC39)
+- Creation of new specifications outside of standards bodies
+(e.g. similar to the LLVM object file format documentation in Wasm tool conventions)
+
+### Non-normative reports
+The Subgroup may produce non-normative material such as requirements
+documents, recommendations, and use cases.
+
+### Software
+The Subgroup may produce software related to Wasm system interface APIs (either
+as standalone libraries, tooling, or integration of interface-related
+functionality in existing CG software such as Binaryen or WABT). Capabilities may
+include:
+- Libraries implementing external standard APIs in terms of WebAssembly
+  System Interface APIs
+- Tools for producing code that uses WebAssembly System Interface APIs
+- Tools for implementing WebAssembly APIs
+- Tools for debugging programs using WebAssembly System Interface APIs
+
+## Amendments to this Charter and Chair Selection
+
+This charter may be amended, and Subgroup Chairs may be selected by vote of the full
+WebAssembly Community Group.
+

README.md

@@ -2,16 +2,24 @@
 
 ![WASI](WASI.png)
 
-This repository accompanies the WebAssembly WASI Subgroup,
-focused on the design of the WASI, the WebAssembly System Interface.
+This repository is for the WebAssembly System Interface (WASI) Subgroup of the
+[WebAssembly Community Group]. Its [Charter] describes the goals, scope and
+deliverables of the group. The repository may contain meeting notes, reports,
+documentation, specifications and/or software produced by the group (although
+larger projects may also have their own repositories).
 
-We'll be adding more content here, but for now, check out these:
+[WebAssembly Community Group](https://www.w3.org/community/webassembly/)
+[Charter]: Charter.md
+
+We'll be adding more content here before long, but for now, check out these:
  - https://hacks.mozilla.org/2019/03/standardizing-wasi-a-webassembly-system-interface/ - Blog post introducing WASI
- - https://wasi.dev/ - Links to more information about WASI
+ - https://wasi.dev/ - Links to more information about WASI, including
+   how to get started using it.
  - https://github.com/WebAssembly/WASI/issues - This repo's issue tracker
 
 The issue tracker is the place to ask questions, make suggestions, and start
 discussions.
 
-As a W3C CG Subgroup, we'll also be having meetings. Once we have a schedule
-for those, we'll post that here also.
+As a W3C CG Subgroup, we'll also be having [meetings](meetings/README.md).
+A tentative agenda for the first meeting is [here](https://github.com/WebAssembly/WASI/blob/master/meetings/2019/WASI-liftoff.md).
+Once we have a date and time, we'll post that here also.