[Sois-app] Green book review comments

[Richard Melvin]

P4-18: on the ground, calibrations are typically done by configuring the
ground software with a calibration table, not extending/implementing it.
Suggest a slight rewording.

 

P4-19: XAML -> XML, presumably.

 

P4-23: I think the conclusion to be expressed here is that you need:

*         Standardised interfaces for core functionality that will be
acted on directly by software, especially onboard (e.g. AOCS).

*         Device-specific interfaces for information that will be
interpreted by humans, or simple operator-created rules, for diagnostics
and  monitoring.

 

The key point about space hardware is that everything you might need to
know about the device needs to be available through the data interface;
you can't just go up and see if the fault light is blinking.

 

Which means you can't standardise the latter without removing all leeway
in how to build a device. Which is ultimately why you need a device
datasheet in the first place.

 

P5-29: did you manage to validate the sample datasheet using the
tooling? There are a few things in the examples I wouldn't have thought
were valid, and, if they are, perhaps shouldn't be.

 

P5-29: readability would probably be improved by making the point about
xml versus EDS namespaces a footnote.

 

P5-32: I don't think it is right (although it is legal in schema; see
P5-29) that an argument have an encoding. Arguments should only have
ranges. Arguments never get encoded as they are passed over an
interface, they just get restricted to be within range; the semantics
are like a function call not a message exchange. 

You can get the same effect with IntegerBitsRangeType with numberOfBits
= 8; this is just a shorthand for [0-255], without the option to set the
byte order or anything. 

 

P5-33: I think the 'foundation' namespace duplicates/overlaps the
existing 'SEDS' one (in github). There probably should be one such,
delivered alongside the standard (although I don't see that it need to
be standardised itself).

 

P5-35: needs reorganisation, segmentation should perhaps be it's own
topic (saying 'not implemented'), not an aside.

 

P5-44: The idea of 'distribution' of calibrations is new, and maybe
unnecessary. You can get the same effect by definining the calibration
activity with an argument and using Iteration/overArray to call it on
each element.

 

P5-45: per previous discussions, I think the idea of the flag is good,
but the name 'native' is misleading. Interfaces are always going up/down
the OSI protocol stack, so I suggest OSI terminology like SDU or just
dataUnit.

 

P5-54: maybe change 'The namespaces in an EDS' to 'Semantics tags within
the body of an EDS' or similar.

 

P5-56: change example to get rid of multiple devices per datasheet, and
the 'Connect' element? Such things should probably be in some other,
rather more complicated and probably mission-specific schema or model.
One way of doing that would be to define a new top-level schema that
allowed Xincluding devices and namespaces.

 

P5-57: not sure about the example mapping two different interface
parameters to the same local variable; by the red book definition, I
think this would send values read from the device back out to it. Should
either change schema to allow  direct mapping of parameters between
interfaces, or example to use state machine and activities for at least
one of the interfaces.

 

Perhaps worth a warning from the tooling if the same variable is used by
two or more parameter-maps, as I can't see that ever working out.

 

P5-58: the state machine 'read-attitude' seems to be concerned with
setting, not acquiring, data. Definitely needs a state diagram to show
what is going on (the tooling can produce these), I am not at all
convined it is right. 

 

P5-46

>From the point of view of a state machine, it is a _sink_ to
parameters/commands  that trigger transisitons, and a  _source_ of
parameters/commands generated by activities. What that actually means is
different for required and provided interfaces. 

 

That info probably belongs in the current section 3.7, i.e. under common
concepts. 

 

P5-58 S2: I'd agree that doesn't belong here, will make document too
long.

 

richard

 

 

 

 

 

 

 

 

 

 

 



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