Messages

1

General Board / Re: Where did "instance" go?

« on: November 29, 2019, 11:02:13 am »

I don't know where Modesto or Rhys are located (I suspect the UK), but they and I (as examples) have never met and need to be able to communicate unambiguously using only the written word.

I have existed in the UK, but at the time of writing I could not be much further from the UK without being on a boat.  Which is perhaps an interesting example of the need to add a temporal dimension to the representations of modelling, because structural and behavioral dimensions would only be sufficient in a presentist view of reality.

So, let us accept that the things we are modelling can be characterised by their features.
...
Some things are specializations of other things.

This is a useful approach for considering the taxonomy of modelling, but reality is in the opposite direction, where certain things can be considered to exist, and our models abstract away details to either:
1. Create patterns that are sufficiently vague that they can be usefully applied to multiple realities, or
2. Chronicle our journey from optimistic planning free of the burdens of detail through to the robust compromises of delivery

Inheritance and specialization are relevant to that second situation where the journey from platonic ideal to reality may branch to multiple realities (eg. Site A vs. Site B, UAT vs. Prod, Phase 1 vs. Phase 2...)

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General Board / Re: Where did "instance" go?

« on: November 12, 2019, 12:02:52 pm »

Of course, being a Kiwi, you'd mispronounce 'Strine.  But you're forgiven... 

There's a class differentiation.  A person who says 'Strun probably went to a better school than a person who says 'Stroine

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General Board / Re: Where did "instance" go?

« on: November 11, 2019, 11:34:00 am »

many pedants here would say I'm an absolute pedant 

"Absolute" in the sense of undiminished, independent of other things, or a pedant for things that are themselves absolutes?

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General Board / Re: Where did "instance" go?

« on: November 11, 2019, 10:37:53 am »

I'll bite.  What's a "Child Generalization"?  In normal modelling usage, that would be an oxymoron.  Generalization is a directed relationship from the origin (so-called child) to the destination (so-called parent).  Specialization is the antonym of Generalization and therefore directed from the more general to the more specific.

That really is the life blood of this thread.  On the one hand is the canonical forms suggested by the Archimate standard, and on the other is the things that actually happen when you drag Archimate objects from the project browser onto a diagram.

As it stands, if I drag an Archimate technology object (Node, Device, Equipment etc.) onto a diagram I have two choices: Link (ie. put the existing one onto the diagram) or "Child (Generalization)", which is the only way to create a relationship from the existing object to the new thing that is to be represented on the diagram. 

I suppose that another way around the problem would be drag the first object onto the diagram, create a new object of a suitable type, then connect them with a relationship from Toolbox, then remove the first object from the diagram.  However this won't visually embed the relationship in the new object.

Which returns me to my original question, "Where did "instance" go?"

5

General Board / Re: Where did "instance" go?

« on: November 11, 2019, 07:44:33 am »

Just to get this clear in my head out of curiosity:
- Do you have a Node element for the Cisco SGE2000P 24-Port Gigabit Switch without a serial number in the blue or 1st green diagram?
- Do you then create (or want to create) green diagrams where the Cisco SGE2000P 24-Port Gigabit Switch without the serial number is replaced by an instance of it and add the serial number to it?
- What object type does Sparx EA use (or would you Like Sparx EA to use) for the instance?

It varies by how much of the full set of possible documents a project requires.  In the 1st green diagram I used a lot of nodes, but have also started using devices and equipment a lot more lately.

If I am creating a few instances of a thing, then I will make a Node, Device, Equipment or Technology Object in a special folder called "Types".  At the moment I have an Archimate_Node in that folder called "Switch", but if I were doing that again I think it would be a Device.  When I have a diagram with one or more particular switches, then if they are older diagrams they are Instances of that type, and for newer ones they are now Child Generalisations.

Otherwise I often create the instances of the 2nd level green diagram from the objects of the 1st level green diagram.

When it comes to real-world project documentation there are a variety of ways that it will diverge from the idealised set, but they are centred around that ideal even if they are not all carbon copies.

One of the huge advantages of using instances or generalizations rather than raw Archimate objects is that they assume the visual properties of a Class, and you can view or hide the tags.  So for almost every instance I have a tag "IP" that has it's IP address.  Other types of device have other things that are useful to include in tags, such as type (eg. IE-4000-8T4G-E).  That way you can toggle the Tag feature for a diagram to have a clean "just what's there" view, or a more detailed "tell me everything" view that includes details about each box.

6

General Board / Re: Where did "instance" go?

« on: November 08, 2019, 09:41:43 am »

... as a Cisco SGE2000P 24-Port Gigabit Switch - PoE with serial number 123456789-0986 is only persisted on something like the ServiceNow database ...

Not necessarily.  At a large site it is important to plan these things ahead of time so that when the deployment team goes out they put the right thing in the right place.  The first round of planning is "what do we need?", which is the yellow and blue diagrams.  Then there is the "what technical solution are we going to roll out to solve that need?", which is the technology layer (1st green diagrams).  And finally there is the "what is the field technician going to deploy at site #3?" plan which is the equipment/device layer (2nd green diagrams).

Then in the subsequent months or years when people ask, "what ended up at site #3?" you pull out the diagram to show what is there.

Speaking of full circle, it's the 1st to 2nd layer green diagrams where the instance functionality was useful.  I have started using the Child Generalisation option in EA, which may not be canonical Archimate but produces readable diagrams.

7

General Board / Re: Where did "instance" go?

« on: November 06, 2019, 07:56:35 am »

In a rather dramatic development it appears that the Open Group has published a new version of the Archimate standard and has included the new Directed Association relationship https://blog.opengroup.org/2019/11/05/archimate-3-1-specification-the-new-version-of-the-standard/amp/.

If I read this correctly, they have enhanced the "it means anything you like" relationship to allow an arrow and a stereotype, with the ominous warning,

Now you do need to exercise some caution in using this feature. It would not be very helpful, for example, to define your own relationship if something very close is already offered natively by the standard.

  We wouldn't want that to happen now, would we?

I can also picture a scenario where EA including the derived relationships by default would save a lot of "hide this connector in other diagrams" admin.

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General Board / Re: Where did "instance" go?

« on: November 06, 2019, 07:49:02 am »

What is matter anyhow? Do we exist at all? Did(/will) all philosophers die in vain?

I think what Paolo is saying is that there is the real you (probably only known to yourself) and then there is the mythic you - the story you tell the rest of the world.

This is really getting back to Theseus' Ship.  The original ship was an instance of the Platonic ideal of Theseus' Ship, and then at every point where another plank was swapped out it created a new instance of the ship that shared some substance with prior and subsequent instances.  The instances themselves were not the ship itself, which was a technology node rather than a device.

If you were to take the gradual degradation that caused the planks to need to be replaced, then there is an almost infinite series of instances of the ship, so the instances recorded at the swapping of the planks could be determined by a swinging door algorithm on a time series of the decay.

Hope that's helpful.

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General Board / Re: Where did "instance" go?

« on: November 01, 2019, 02:28:26 pm »

I've just learned an embarrassingly large thing via this thread:

Nuance 1 - Technology and physical equipment are not the same thing

Up until now I have conflated the Archimate Technology and Physical layers into one by assuming that they map to the TOGAF D: Technology Architecture domain.  In the words of Job, I will place my hand over my mouth at this point.

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General Board / Re: Where did "instance" go?

« on: October 31, 2019, 09:02:48 am »

Did I say "argument"?  I think I meant "meeting".

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General Board / Re: Where did "instance" go?

« on: October 31, 2019, 08:57:15 am »

In the IT world, the yellow diagrams are for sales people and the project sponsors.  The blue diagrams are the ones that you draw on the whiteboard at the beginning of each argument.  The green ones are what the vendor was supposed to build, and they grow in number and detail as you iterate through the delivery mistakes.

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General Board / Re: Where did "instance" go?

« on: October 31, 2019, 08:47:22 am »

I don't think it's a good idea to jump straight from a business object "BMW X1" to the technology element equipment for "BMW X1 with VIN# 12345".

Personally I prefer to have business objects at the highest level of abstraction (Driver role, Driving function etc.), solution patterns in the application layer (Vehicle has transportation function), and physical implementations in the technology layer (BMW X1 #12345 implements or realises the Vehicle Application Component).

Perhaps the confusion here is the problem of types of implementation.  If we model the driving solution at an application layer, it should be generic enough to be implemented in a variety of ways.  An abstraction in the technology layer is a way of grouping implementation solutions rather than having direct links from the concrete technology implementation back to the abstract application layer (and certainly not directly back to the business layer).

So filling that out, with simplifications and omissions for clarity:

Business Layer - Driver Role carries out the Driving Function as part of the Transportation Process
Application Layer - Motor Vehicle Component realizes the Driving Function, and the Pathway Component is used by the Motor Vehicle Component
Technology layer: Off-Road Pattern - Offroad vehicle device realizes Motor Vehicle Component and uses Muddy Road Node that realises the Pathway Component
Technology layer: On-Road Pattern - On-road vehicle device realizes Motor Vehicle Component and uses Asphalt Road Node that realises the Pathway Component
Technology layer: Off-Road Implementation Pattern - BMW X1 device is a specialization of On-road vehicle device and uses Muddy Road with < 200mm puddles Node that is a specialization of the Muddy Road Node
Technology layer: X1 #12345 Implementation - BMW X1 VIN #12345 device is a realization of BMW X1 device and uses Woodhill Forest Road #2 Node that is a realization of the Muddy Road with < 200mm puddles Node

The other comments will require a bit more reading before I can say something sensible about them.

Note that this is also just a restatement of

The Theseus' ship problem is about levels of abstraction,

• a Switch is a concept, it does not belong to the technology or physical views (though) with a somersault you may be able to squeeze it into the the logical view)
• a Switch in a guard house is a logical element, it belongs to the technology view
• the Switch in the guard house of Bishop Rock in the Isles of Scilly (assuming there is one) is physical equipment and belongs to the physical view

13

General Board / Re: Where did "instance" go?

« on: October 29, 2019, 07:00:44 am »

Do you remember the name of the tool or the company?  It doesn't appear on the 3rd party list:  https://sparxsystems.com/products/3rdparty.html

14

General Board / Re: Where did "instance" go?

« on: September 26, 2019, 11:36:07 am »

The more tangible entity (source) realizes (makes real) the more abstract entity (target).

So in the passive voice convention of ArchiMate, the Realized by arrow goes from abstract to tangible to show the relationship you have described?

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General Board / Re: Where did "instance" go?

« on: September 26, 2019, 11:04:21 am »

So does the "Realized by" arrow point from the logical switch to the technology one, or the other way around?

ArchiMate relationships should form a coherent English sentence when read from source to target.  They're also generally the opposite direction to UML.

I always thought that too.  So the "Realized by" arrow should point from blue (logical) to green (technology).  Ie. The switch in the guard room instance of the camera plus switch logical pattern is realised by a IE-4000-4T4P4G-E.

However I have seen a lot of green to blue "Realized by" arrows, including in Gerben Wierda's Mastering Archimate, so I am beginning to doubt my understanding of it.