[evla-sw-discuss] RTOSes ?

[Kevin Ryan]

Thank you for your comments John.  I don't believe we've met; my
name is Kevin Ryan and I'm a programmer in the ASG group.

At the risk of straying away from the multiple RTOS subject, I
would like to explain some of where we are with the MIB.  Keep in 
mind that nothing is set in stone and lively debate is ongoing.

You wrote:
> 
> I also think that the MIB should be more like the VLBA SIB and less
> like a full-blown station computer.  There are many reasons, but chief
> among them is that hardware developers need a simple reliable
> interface to attach to their designs *early* in the project, so that
> they can do useful debugging and testing of their designs without a
> lot of software support.  I would err on the side of making the MIB
> dumber, rather than smarter.
> 

This is a good point and is echoed by the hardware folk.  It is
intended that the MIB will start out as a simple 'get/set' memory-
mapped type interface to the hardware component being developed.
This simple interface will evolve into the permanent Module Driver
portion of the MIB software; one of three proposed sections of MIB 
software.

One important requirement imposed on the MIB is that it be able to
speak some sort of internet protocol (such as TCP/IP) over Ethernet.
This means that our MIB will begin life as an already complex device.
However, this is not a bad thing because it will give the hardware
engineers a powerful interface to the MIB during development.

The Ethernet driver (MIB Frontend) is the second of the three 
sections of software.  The third is the hardware component 
functionality (personality?) software which will utimately 
represent the hardware component to which the MIB is attached.

The MIBs will probably be developed in two phases.  The Module and
Ethernet drivers will be developed first so that the hardware 
engineers can get to work.  The h/w engineers will probably 
develop their own backend software while the ASG group does the 
frontend.  

The second phase will be the personality software and it is here
where most of our opinions differ.  Some want little or no 
functionality at this point and want to move it up into the Antenna 
Control Computer or even the Array Control Computer.  Others want 
to keep the expert knowledge of the controlled device in this layer 
of software.

So, no matter how we do the second phase, our MIBs will have to 
be at least complex enough to support the frontend and backend
drivers - with the Ethernet frontend being the most demanding.

Kevin