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What is an Information System?

An Introduction

Generations

Computer Hardware and Software have come a long way since digital computing was first conceived. As each major technological breakthrough heralded a new hardware generation, software too progressed in sophistication:

Gen
Hardware
Software
1

Mechanical Computers

Physical switching technology (eg. "steam driven" calculating machines)

Binary

Instructions respresented as a sequence of 1's and 0's. Very low level, verbose but executed directly on transistors

2

Vacuum Tube- Based Computers

Vacuum tubes (specialised 'bulbs') perform the same job switches did in mechanical computers (2 states = ON/OFF). Huge, hot and fragile, took time to 'warm up'.

2GL-ASM

Mnemonic Binary= Assembler Language. Clusters of binary instruction codes given a name (eg. MOV, POP, AND). Low level, verbose, executed via 'instruction sets' burnt on to IC's.

3

Transistor-Based Computers

Each 'tiny' transistor did the same job as a valve (ie. provided an on/off switch). Invention heralded the 'solid state' revolution in consumer radios and other electronic goods.

3GLs

Procedural Languages - say what you want to happen and provide instructions for how you want it to be done as well (eg. Pascal, BASIC, COBOL, FORTRAN, C). Clusters of ASM codes grouped under named instructions (eg. PRINT, READ). Relatively high level english-like instructions, interpreted into ASM before executed.

4

Integrated Circuit-Based Computers

Many microscopic transistors etched onto a single silicon chip - miniaturisation with the 'computer on a chip'.

4GLs

Declaritive Languages - say what you want to happen, not how (eg. SQL, PROLOG, LISP). High level, compact english-like commands

5

Massive Parallel Processing

Multiple processors sharing the tasks, huge bandwidth (in it's infancy currently)

5GLs

Natural Language with ability to convert near normal (or formalised) communication into commands - understanding context and intention. Not available yet.

 

Database Components

There are typically 3 components to a traditional '70s style Info Sys.

  • Database = the set of stored facts or propositions
  • DBMS = DataBase Management System, that operates on the database and provides the means for retrievals, updates etc.
  • Application Programs = providing a human-computer interface, ('friendly front-end'), generally menu or command driven, provide a 'relatively' easy means of communication with the DBMS which then operates on the DB

Allied Concepts:

  • data representation - the 'physical' representation of the data (on the disk, say)
  • independence - whether the system could be run on different hardware
  • redundancy - the storage of a particular fact in more than one place, or the storage of a fact that is an amalgam of other facts - leads to update anomalies and possibly inefficient data representation.
  • query capability - an 'english' like language for 'ad-hoc' enquires and requests
  • performance - response time - application specific
  • optimization - ensuring the operational performance is as fast and as direct as possible
  • cost effectiveness - including design, implementation, population and maintenance (possibly on-going)
  • security - protection against unauthorised access
  • integrity - 'correctness' and consistency of stored facts

Fifth Generation Information Systems (5GIS)

It has been proposed that an Information System based on a 5th Generation Language could differ from it's predecessors radically.

There would be two main transaction types when using a 5GIS:

  1. Specification of the Universe Of Discourse (UoD). The UoD of an information system is the entire description, of all facts and relationships that exist in the situation being modelled by the IS

  2. Querying the system about the UoD

Although true 5GIS's don't yet exist, much work has been done towards that goal, with early DB research still aiming at the relational ideal.

When building an 'old style' database, most effort is expended in the implementation stages (the building of the storage containers, interface and controlling the DB management system and client programs).

When building a 5GIS, most of the work is done in the design stage, where a complete formal description of the UoD is complete with facts (both type and context), rules governing these facts and constraints. Implicit in the specification of the UoD are all of the constraints and derivations that would have been handled by client programs in an old style database.

Turings Test Of Intelligence

It is suggested that one of the important building blocks for a true 5GIS is an interface that displays intelligence - but how do we guage intelligence?

turings test

Alan Turing proposed a test involving humans conversing with other humans and computers. In this test, Human A 'converses' via 'chat' software with person B (male pretending to be female) on the otherside of an opaque wall (via a computer terminal) in natural language about a desired topic. Human B eventually hands over the conversation to Machine C.

IF A can tell the difference between B and C
           then the machine IS NOT intelligent
           else the machine IS intelligent

To date, NO computer has passed this test... however, on restricted topics and using some formalisation of the 'natural language' used in the conversation, some computers have performed at a 'human' level or better.

eg. Chess computers, Blood disorder diagnosis (so-called 'Expert systems' where the UoD is specified and NARROW)

Universe Of Discourse

 
           human         <------------>        human
                (natural language communication)
           human         <------------>        5GIS

Using FNL (Formalised Natural Language - which has specific conventions, syntax and allowances for cultural differences in expression), communication with a 5GIS should be similar to communicating with a human educated in that field.

 

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