Steve Jones wrote: > On 13/12/06, Hitoshi Ozawa <[EMAIL PROTECTED]> wrote: > >> >> Hi Steve, >> >> Walmart and their supplier may provide or use a service, but they aren't >> services. >> > > Why not? Walmart Inc provide a "service" to their shareholders. A > supplier will provide a service to Walmart at a business level. > > Just what I said. Walmart "provides" a service. I think we agree on this point.
> I'm rather a big fan of recognising business services that can't be > implemented in IT. > > >> I don't think benefit of loosely coupling is the ability to more easily >> change suppliers. >> IMHO, I think it's more of being able to change services and >> relationship between them. >> > > You are talking at a technical level here I guess? > > >> As an example, I think Walmart is experimenting with RFID. The change >> from barcode >> to RFID may involve change in how shipment/recieve/purchase order are >> processed. >> If the currently system is tightly coupled, this change in technology >> will require major >> modification to the current software/system to obtain the maximum >> benefit from the >> new technology. >> > > It might not, if the current system is one big blob of code but the > barcode is stored as an EPC standard format then there is nothing to > stop them shifting it to the RFID ID. > > Now if what you are arguing is that you might want to change the > _order_ of certain steps and the _order_ that certain services are > called then I'm 100% with that, as with introducing or removing > specific service from a process. In someways the simplest thing that > would work here is to have everyone running off the same backend > system so they share the same data and context (like the way ERPs > work), but this is massively tightly coupled and not so hot if you > want to involve things external to the system/ERP. > > As you pointed out, it isn't very difficult to just switch barcode codes with RFID IDs, but that would just increase the cost because RFID tags are more expensive than barcodes. As you pointed out, to gain benefits from the change, it is important to change the "order" or rearrange the service relationships. I think we agree on this point too. > So coupling is for me a question of "sensible coupling" rather than an > all out pursuit of "loose coupling". > > Can you expound on what you mean by "sensible coupling"? Cheers, H.Ozawa
