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Weekly Meeting: 2014-04-15
By Dave Scott - 2014-04-15


  • GSoC/OPW
  • OCaml-Conduit
  • Vchan
  • Irminsule status
  • ARM
  • Mirage tutorial day
    • Using Codio

Attendees: Amir Chaudhry (chair), Jonathan Ludlam, Anil Madhavapeddy, David Scott, Thomas Leonard, Thomas Gazagnaire



We have 2: (a) and (b). For (a): shall we do IPv6 or fuzz testing? Thomas points out that IPv6 is good marketing. JonL described his xen-testvm which can be used to emit packets, read and write block etc. (b) will probably work on the cloud API bindings (mainly mentored by Dave). Claims were made about Dave being the God of clouds.s


Anil wrote ocaml-conduit (source), which is a nice API to open SSL connections. Abstracts a layer and allows us to swap something else in the back. In future it will support other types of connections and clean-slate SSL stacks (e.g OCamlTLS). It was quite a big rewrite. We should use it everywhere were we want to open connections (e.g. SSL clients). David Sheets is back soon so will resume some of his SSL work too.


Currently only used by xen-testvm, which isn't currently building because it's pre-Mirage 1.0. Anil points out that the magic conduit library can could also have vchan support but needs someone to look at this. JonL has agreed to this and will add vchan support to ocaml-conduit.


Thomas reports that merging is working (more or less). He's started to work on a dispatcher, where you can assemble together different backends (memory, disk, ...). You will be able to decide which backend to use based on the key, provided first class modules are up to the task.

This means we can (almost?) do logging now. Can run a VM with a collector for this. Anil is keen to try putting together an IRC bouncer. Dave has tried Irminsule on Xenstore. Git push is still outstanding although Irminsule push somewhat works. Just need to get core_kernel compiling with it. Everyone is invited to try it out and please submit feedback via the bug tracker.


Thomas Leonard has been getting Anil's stuff to work on the Cubieboard. Hit a bug in Xen causing the hypervisor to crash. Now that's fixed, the miniOS VM is running and printing stuff on the screen; it could be replaced with Mirage. ThomasL has started looking at FreeBSD.

Anil suggests hooking up the console ring to MiniOS to log on the regular console rather the debug console. Anil suggested that it might be a good time to re-integrate the OCaml runtime with miniOS, since the current integration is a little bit hacky. Perhaps after FreeBSD it would be good to figure out the easiest strategy.

Mirage Tutorial day

Amir says: We need to discuss a date.
Anil: We don't have a location!
Anil says: Why not just say Jun 11?

The date needs to be discussed and confirmed so this is not final. Venue is likely to be the Computer Laboratory and previous discussions regarding the content and target audience can be found in earlier notes (i.e 2014-04-01 and 2014-03-18).

Using Codio

Amir was due to try out Codio for this meeting but hasn't had time yet. It seems to work well enough for the RWO guided tour so he's not anticipating any issues. Will try and work through a complete example for next time (e.g building the mirage website).


Amir proposed using the Mirage-www repo wiki to keep track of upcoming agenda items. Will save Dave from having to dig through his email between calls and thus avoid agenda items being forgotten. Amir will set this up and then hand over to Dave to maintain.