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/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
vim:expandtab:autoindent:tabstop=4:shiftwidth=4:filetype=c:cindent:
*/
/** \page overview_overview Libsmbios Overview
\section overview_reasoning Libsmbios - A BIOS Access library
Many BIOS tools exist today. However, there are few, if any, libraries for
accessing BIOS information. Libsmbios was designed with the following goals
in mind.
\subsection overview_goals Libsmbios Goals
\li Best-practice design principles
\li Extensible Access to SMBIOS Information
\li Ability to perform unit tests across multiple systems \a without \a using \a physical \a hardware
\li Centralized, data-driven exception handling for broken BIOS tables
\section overview_best_practice_design Best-Practice Design Principles
Libsmbios uses the current best-practice in design principles:
\li Abstract Factory pattern
\li Dependency Inversion Principle
\li Observer/Observable pattern
\section overview_extensible Extensible Access
Libsmbios provides two layers of access to BIOS data. The first layer uses
table numbers, address, and offsets to access data. An example is the using
table number 0, offset 5 to access the BIOS Version string inside the SMBIOS
BIOS Information table. This layer relies on the basic formats of each BIOS
interface, i.e. the table format of SMBIOS is standardized. Therefore, new
tables can be accessed through layer 1 even though the code has no knowledge
of the new table content.
The second layer uses XML to model BIOS data. The XML file contains
human-readable strings to identify table numbers, address, and offsets. To
build on the example above, the same data could be accessed as
"BIOS Information", "BIOS Version". Layer 2 uses the XML to interpret the
type of data within the table. At layer 1, the code can only provide the
integer value 0x02040020. At layer 2, the code can identify that the value
is a bit field and, according to the XML, means that PCI, ISA, EISA, and Boot
from CD is supported by the BIOS. Naturally, layer 2 accesses data through
layer 1 with the enhanced capabilities of XML modeling.
The image below shows the logical model of the Libsmbios design. This should
not be misinterpreted as a class diagram or hierarchy. For that type of
information, please see the Class Hierarchy page.
\image html InterfaceLogicalModel.jpg "Logical Model of Libsmbios"
\section overview_unittest Unit Test Design
Software-based unit testing of the Libsmbios code is one of the key features
of the library. Simply put, over 80% of the code path can
be tested without the use of hardware platforms. This is possible because
layer 1 is designed to use files or memory interchangeably when accessing
BIOS data. That means the memory of a particular server can be dumped to a
file and stored in a unit test tree. Every time the code is unit-tested it
can use memory files from multiple servers as input. There is no limit to
the number of these "virtual systems" that can be captured, stored, and tested
in the unit test framework.
The image below shows the use of multiple virtual systems within the unit test
framework.
\image html UnitTestLogicalModel.jpg "Unit Testing of Libsmbios"
*/
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