Solution Decisions for Delivery of Part One

Revision A - 11 APR 1996

Abstract

This document includes the following decision topics:

The final topic, Decisions Summary, describes the impact of the decisions made.

NOTE: After discussions with the customer an overall solution decision to use LCA was made.

1 Hardware

Alternatives
  1. Any non-Intel platform (e.g. SPARC or PowerPC).

  2. Intel platform (running WindowsNT / Windows95 or OS/2).

Decision
Due to the fact that the price differences between the alternatives were marginal, any of the above could have been chosen if the price was the major concern. In this case however, the total solution involved LCA. To our best knowledge LCA is only available for WindowsNT and Windows95. Therefore alternative 1 was out of the question. Hardware decision: Intel x86 platform.

2 Operating System

Alternatives
  1. Windows95.

  2. WindowsNT.

  3. Windows 3.x

  4. OS/2.

  5. Unix.

Decision
Once again, the choice of LCA eliminated most of the alternatives (in this case 3, 4 and 5). Due to the fact that WindowsNT 4.0 (supporting Network OLE) probably will not be released before this summer and that major problems occurred trying to run LCA under WindowsNT, alternative 2 was out of the question.

Operating System decision: Windows95.

3 Programming Language/Environment

Alternatives
Decision
Due to its major advantages, mostly different kinds of C++-clones have been considered. But also other languages such as Visual Basic and Smalltalk have been taken under consideration. However, the following advantages with Visual C++ made the decision fairly easy:

Programming Language/Environment decision: Visual C++.

4 Communication

Alternatives
  1. Shared memory.

  2. OLE2.

  3. OpenDoc.

  4. Network OLE.

Decision
Since the most attractive alternative (number 4) had about all the features needed (client/server communication and running under WindowsNT) alternative 1-3 was at first not even considered. We first took alternative 4 (running on a WindowsNT) as an obvious choice due to being a Microsoft invention (certain to survive as a widely supported standard), but pretty soon had to reconsider the choice b ecause we understood that Network OLE probably wouldn't be available in time. After a lot of consideration (read - close to delivery date) we chose to use a combination of alternative 1 and 2, in order to get as close as possible to the functionallity of Network OLE. The only problem with this decision is that it doesn't at all support the network communication functionallity intended. This probl em has been postponed.


Communication decision: Shared memory and OLE2.

5 Decisions Summary

Hardware: Intel x86.

OS: Windows95.

Prog. Lang./Env.: Visual C++.

Communication: Shared Memory combined with OLE2.

There are probably only one thing uncertain, considering our solution decision, and that is the decision to use a combination of Shared Memory and OLE2 to manage the communication taking place. As stated above this decision was taken mostly due to lack of time. The combination works like this; the WWW Interface makes use of shared memory when communicating with the Data Server, and the Data Serve r in turn communicates with LCA via OLE2. There is a problem present with this solution (see [4], "Communication"), but it only concerns future deliveries, thus doesn't affect the functionallity of the parts delivered in this delivery.

6 Terminology

LCA Echelon's product and standard for how to handle Neuron nodes. Implemented using OLE.

OLE Object Linking and Embedding. Microsoft's architecture to enable program components to cooperate and share data in a standardized way.

OpenDoc A competing standard supported by IBM and Apple.

Solution Decisions for Delivery of Part One
Abstract
1 - Hardware
Alternatives
Decision
2 - Operating System
Alternatives
Decision
3 - Programming Language/Environment
Alternatives
Decision
4 - Communication
Alternatives
Decision
5 - Decisions Summary
6 - Terminology
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© 1996, The SAIDA Project