Page 153 - DCAP308_OBJECT_ORIENTED_ANALYSIS_AND_DESIGN

Unit 12: System Design

The model that Zing uses (to check for program correctness) has to be created either by Notes
hand or by translators. While some specific domain translators can be written, we have
yet to come across any complete and successful translators for native or CLR applications.
Without having translators, we believe Zing cannot be used in large software projects,
except for verifying the correctness of critical subsections of the project.

12.2.4 Allocation

You must allocate each concurrent subsystem to a hardware unit, either a general-purpose
processor or specialized functional unit. The system designer must do the following:

Estimate performance needs and the resources needed to satisfy them.
Choose hardware or software implementation for subsystems
Allocate software subsystems to processors to satisfy performance needs and minimize
inter processor communication
Determine the connectivity of the physical units that implement the subsystems.
Consider the connection between nodes and communication protocols to be used.
Consider the need for redundant processing.

Identify any interface implied by deployment.
UML deployment diagram can be used to present the above-mentioned steps. A deployment
diagram shows how the systems will be physically distributed on the hardware.

12.2.5 Management of Data Storage

There are several alternatives for data storage that you can use separately or in combination:
data structures, files and databases. Different kinds of data stores provides trade-offs among
cost, access time, capacity and reliability.
Database

These are the advantage and disadvantage using database.
Advantages

Efficient management
Multi-user support.
Roll-back support

Disadvantages

Performance overhead
Awkward (or more complex) programming interface

Hard to fix corruption
Flat Files

These are the advantage and disadvantage using File.

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