Analytical Network and System Administration

Managing Human-Computer Networks

Mark Burgess

• Publisher: Wiley
• Year: 2012
• ISBN:
  9781118604465
• Edition: 1
• Topic: Technologie et ingénierie
• Subtopic: Ingénierie de l'électricité et des télécommunications

Networkandsystem administration usually refers to the skill of keeping computers and networks running properly. But in truth, the skill needed is that of managing complexity. This book describes the science behind these complex systems, independent of the actual operating systems they work on.

It provides a theoretical approach to systems administration that:

• saves time in performing common system administration tasks.
• allows safe utilization of untrained and trained help in maintaining mission-critical systems.
• allows efficient and safe centralized network administration.

Managing Human-Computer Networks:

• Will show how to make informed analyses and decisions about systems, how to diagnose faults and weaknesses
• Gives advice/guidance as to how to determine optimal policies for system management
• Includes exercisesthat illustrate the key points of the book

The bookprovides a unique approach to an old problem andwill become a classic for researchers and graduate students in Networking and Computer Science, as well as practicing system managers and system administrators.

Chapter 1

Introduction

Technology: the science of the mechanical and industrial arts.
[Gk. tekhne art and logos speech].

—Odhams dictionary of the English language

1.1 What is system administration?

System administration is about the design, running and maintenance of human–computer systems. Human–computer systems are ‘communities’ of people and machines that collaborate actively to execute a common task. Examples of human–computer systems include business enterprises, service institutions and any extensive machinery that is operated by, or interacts with human beings. The human players in a human–computer system are often called the users and the machines are referred to as hosts, but this suggests an asymmetry of roles, which is not always the case.

System administration is primarily about the technological side of a system: the architecture, construction and optimization of the collaborating parts, but it also occasionally touches on softer factors such as user assistance (help desks), ethical considerations in deploying a system, and the larger implications of its design for others who come into contact with it. System administration deals first and foremost with the system as a whole, treating the individual components as black boxes, to be opened only when it is possible or practical to do so. It does not conventionally consider the design of user-tools such as third-party computer programs, nor does it attempt to design enhancements to the available software, though it does often discuss meta tools and improvised software systems that can be used to monitor, adjust or even govern the system. This omission is mainly because user-software is acquired beyond the control of a system administrator; it is written by third parties, and is not open to local modification. Thus, users’ tools and software are treated as ‘given quantities’ or ‘boundary conditions’.

For historical reasons, the study of system administration has fallen into two camps: those who speak of network management and discuss its problems in terms of software design for the management of black box devices by humans (e.g. using SNMP), and those who speak of system administration and concern themselves with practical strategies of machine and software configuration at all levels, including automation, human–computer issues and ethical considerations. These two viewpoints are complementary, but too often ignore one another. This book considers human–computer systems in general, and refers to specific technologies only by example. It is therefore as much about purely human administrative systems as it is about computers.

1.2 What is a system?

A system is most often an organized effort to fulfil a goal, or at least carry out some predictable behaviour. The concept is of the broadest possible generality. A system could be a mechanical device, a computer, an office of workers, a network of humans and machines, a series of forms and procedures (a bureaucracy) etc. Systems involve themes, such as collaboration and communication between different actors, the use of structure to represent information or to promote efficiency, and the laws of cause and effect. Within any mechanism, specialization of the parts is required to build significant innovation; it is only through strategy of divide and conquer that significant problems can be solved. This implies that each division requires a special solution.

A computer system is usually understood to mean a system composed primarily of computers, using computers or supporting computers. A human–computer system includes the role of humans, such as in a business enterprise where computers are widely used. The principles and theories concerning systems come from a wide range of fields of study. They are synthesized here in a form and language that is suitable for scholars of science and engineering.

1.3 What is administration?

The word administration covers a variety of meanings in common parlance. The American Administration is the government of the United States, that is, a political leadership. A university administration is a bureaucracy and economic resource department that works on behalf of a board of governors to implement the university’s policy and to manage its resources. The administrative department of a company is generally the part that handles economic procedures and payment transactions. In human–computer system administration, the definition is broadened to include all of the organizational aspects and also engineering issues, such as system fault diagnosis. In this regard, it is like the medical profession, which combines checking, management and repair of bodily functions. The main issues are the following:

• System design and rationalization
• Resource management
• Fault finding.

In order to achieve these goals, it requires

• Procedure
• Team work
• Ethical practices
• Appreciation of security.

Administration comprises two aspects: technical solutions and arbitrary policies. A technical solution is required to achieve goals and sub-goals, so that a problem can be broken down into manageable pieces. Policy is required to make the system, as far as possible, predictable: it pre-decides the answers to questions on issues that cannot be derived from within the system itself. Policy is therefore an arbitrary choice, perhaps guided by a goal or a principle.

The arbitrary aspect of policy cannot be disregarded from the administration of a system, since it sets the boundary conditions under which the system will operate, and supplies answers to questions that cannot be determined purely on the grounds of efficiency. This is especially important where humans are involved: human welfare, permissions, responsibilities and ethical issues are all parts of policy. Modelling these intangible qualities formally presents some challenges and requires the creative use of abstraction.

The administration of a system is an administration of temporal and resource development. The administration of a network of localized systems (a so-called distributed system) contains all of the above, and, additionally, the administration of the location of and communication between the system’s parts. Administration is thus a flow of activity, information about resources, policy making, record keeping, diagnosis and repair.

1.4 Studying systems

There are many issues to be studied in system administration. Some issues are of a technical nature, while others are of a human nature. System administration confronts the human–machine interaction as few other branches of computer science do. Here are some examples:

• System design (e.g. how to get humans and machines to do a particular job as efficiently as possible. What works? What does not work? How does one know?)
• Reliability studies (e.g. failure rate of hardware/software, evaluation of policies and strategies)
• Determining and evaluating methods for ensuring system integrity (e.g. automation, cooperation between humans, formalization of policy, contingency planning etc.)
• Observations that reveal aspects of system behaviour that are difficult to predict (e.g. strange phenomena, periodic cycles)
• Issues of strategy and planning.

Usually, system administrators do not decide the purpose of a system; they are regarded as supporting personnel. As we shall see, this view is, however, somewhat flawed from the viewpoint of system design. It does not always make sense to separate the human and computer components in a system; as we move farther into the information age, the fates of both become more deeply intertwined.

To date, little theory has been applied to the problems of system administration. In a subject that is complex, like system administration, it is easy to fall back on qualitative claims. This is dangerous, however, since one is easily fooled by qualitative descriptions. Analysis proceeds as a dialogue between theory and experiment. We need theory to interpret results of observations and we need observations to back up theory. Any conclusions must be a consistent mixture of the two. At the same time, one must not believe that it is sensible to demand hard-nosed Popper-like falsification of claims in such a complex environment. Any numbers that we can measure, and any models we can make must be considered valuable, provided they actually have a sensible interpretation.

Human–computer interaction

The established field of human–computer interaction (HCI) has grown, in computer science, around the need for reliable interfaces in critical software scenarios (see for instance Sheridan (1996); Zadeh (1973)). For example, in the military, real danger could come of an ill-designed user interface on a nuclear submarine; or in a power plant, a poorly designed system could set off an explosion or result in blackouts.

One can extend the notion of the HCI to think less as a programmer and more as a physicist. The task of physics is to understand and describe what happens when different parts of nature interact. The interaction between fickle humans and rigid machinery leads to many unexpected phenomena, some of which might be predicted by a more detailed functional understanding of this interaction. This does not merely involve human attitudes and habits; it is a problem of systemic complexity—something that physics has its own methods to describe. Many of the problems surrounding computer security enter into the equation through the HCI. Of all the parts of a system, humans bend most easily: they are often both the weakest link and the most adaptable tools in a solution, but there is more to the HCI than psychology and button pushing. The issue reaches out to the very principles of science: what are the relevant timescales for the interactions and for the effects to manifest? What are the sources of predictability and unpredictability? Where is the system immune to this interaction, and where is the interaction very strong? These are not questions that a computer science analysis alone can answer; there are physics questions behind these issues. Thus, in reading this book, you should not be misled into thinking that physics is merely about electrons, heat and motion: it is a broad methodology for ‘understanding phenomena’, no matter where they occur, or how they are described. What computer science lacks from its attachment to technology, it must regain by appealing to the physics of systems.

Policy

The idea policy plays a central role in the administration of systems, whether they are dominated by human or technological concerns.

Definition 1 (Policy—heuristic) A policy is a description of what is intended and desirable about a system. It includes a set of ad hoc choices, goals, compromises, schedules, definitions and limitations about the system. Where humans are involved, compromises often include psycholo...

Table of contents

• Cover
• Half Title page
• Title page
• Copyright page
• Foreword
• Preface
• Chapter 1: Introduction
• Chapter 2: Science and its methods
• Chapter 3: Experiment and observation
• Chapter 4: Simple systems
• Chapter 5: Sets, states and logic
• Chapter 6: Diagrammatical representations
• Chapter 7: System variables
• Chapter 8: Change in systems
• Chapter 9: Information
• Chapter 10: Stability
• Chapter 11: Resource networks
• Chapter 12: Task management and services
• Chapter 13: System architectures
• Chapter 14: System normalization
• Chapter 15: System integrity
• Chapter 16: Policy and maintenance
• Chapter 17: Knowledge, learning and training
• Chapter 18: Policy transgressions and fault modelling
• Chapter 19: Decision and strategy
• Chapter 20: Conclusions
• Appendix A: Some Boolean formulae
• Appendix B: Statistical and scaling properties of time-series data
• Appendix C: Percolation conditions
• Bibliography
• Index