Required reading
	---------------------------------------------------------
	Textbook	Laudon & Laudon 1995 Ch. 6, pp. 178-189, 205-210 Ch. 7, pp. 220-233
	---------------------------------------------------------

Overview

In Chapter 6 in Laudon and Laudon you are given an introduction to systems software and applications software. Later in this unit you will be required to do some simple programming yourself in the Basic language. That experience should make the concepts explained in this module more concrete. You will be carrying out the processes described on pages 188 and 189-writing source code in the Basic language, then using a Basic language interpreter to produce and run machine code.

In Chapter 7 you are given an introduction to different types of file organisation and databases. A knowledge of file organisations and processing is important if you ever do any programming. This knowledge is also important if you are using a database package (like dBase) as the database structure is still based on a number of individual 'files'. You should appreciate why the creation of an index for a file (or table) will speed up processing.

You will do more on databases, including practical work, in a subsequent unit, 25232 Information Systems IB.

Review questions

REVIEW QUESTION 4-1	Textbook	Laudon & Laudon 1995 p. 216, Discussion question 2.
REVIEW QUESTION 4-2	Textbook	Laudon & Laudon 1995 p. 252, Review questions 1 to 7.
REVIEW QUESTION 4-3	Textbook	Laudon & Laudon 1995 p. 253, Discussion questions 1, 2.

Quiz

Mark the correct answer.

QUESTION 1

Which list is in the correct order?
(a) application software, people, system software, hardware
(b) people, application software, system software, hardware
(c) hardware, application software, system software, people
(d) hardware, people, application software, system software
(e) system software, application software, hardware, people

QUESTION 2

A master control program that oversees computer operations and coordinates all of the computer's work is called the:
(a) supervisor
(b) compiler
(c) utility
(d) modem
(e) multiplexer.

QUESTION 3

When multiple programs employ the computer's resources at the same time through concurrent use of the CPU, it is called:
(a) multiplexing
(b) multiprogramming
(c) multiprocessing
(d) multifiling
(e) multiresourcing.

QUESTION 4

Processing a key mathematically in order to find a storage location is:
(a) verifying
(b) hashing
(c) sequencing
(d) packing
(e) blocking.

QUESTION 5

The randomizing algorithm makes use of what mathematical concept?
(a) calculus
(b) algebra
(c) binary numbers
(d) hexadecimal numbers
(e) prime numbers

Put a tick in the appropriate box.	True	False
QUESTION 6
The operating system allocates and assigns system resources.
QUESTION 7
Multiprocessing is the use of two or more CPUs linked together to work in parallel.
QUESTION 8
A collection of related fields is a record.
QUESTION 9
An index permits faster access to data in a large file.
QUESTION 10
When using a database, data are independent of application programs.

Answers to quiz

Question 1.	(b)
Question 2.	(a)
Question 3.	(b)
Question 4.	(b)
Question 5.	(e)
Question 6.	T
Question 7.	T
Question 8.	T
Question 9.	T
Question 10.	T

Answer pointers to Review questions

Taken from Simmons (1995).

REVIEW QUESTION 4-1

2. The trend in software has been toward increasing ease of use by nontechnical people. Some "fourth-generation" software already in use has natural language features, where commands are expressed in English language form. Voice recognition software allows users to communicate with computers through spoken commands. In the future, software will feature more prominent use of such natural language tools as well as graphic interfaces, touch screens, the computer mouse and other features that will make software "friendlier" to nontechnical specialists. However, sophisticated voice recognition software will be more difficult to develop because current products can only handle limited vocabularies.

REVIEW QUESTION 4-2

1. File organization and management allows users to organize and structure data so that it can be utilized effectively for problem solving. Without organization, data may not be easily available or in the right form. When this happens, the information system cannot achieve its purpose.

2. In order from simplest to most complex, they are:

   Bit: The smallest unit of information in a computer system.

   Byte: A single character, which can be a letter, number, or other symbol. Each byte is composed of a unique string of bits.

   Field: A grouping of characters into a word or complete number. Each field consists of a series of bytes.

   Record: A collection of related data fields describing the subject of the record such as course number, professor's name, and room number.

   Database: A group of related files such as the registrar's file, the bursar's file, and the admissions file.

3. Key fields provide a means of uniquely identifying records so that they can be located, retrieved, updated, and sorted. Indexes are listings of key fields showing where the associated records are physically stored. Without these tools, it is extremely difficult to utilize stored information.

4. The indexed sequential access method (ISAM) allows for direct access of individual records, without searching the preceding records, by employing an index of record addresses while the sequential access method requires that records be searched one by one in their physical order.

   Both ISAM and the random access method allow direct access to individual records. As its name implies, the indexed sequential access method uses an index of key fields to accomplish this. The random access method does not use an index. Instead, it uses a mathematical formula called an algorithm to calculate the physical storage location of a record.

5. A database is a collection of data arranged so that it can be accessed and utilized by many different application programs by centralizing the data in one physical location. A data base management system is the software which makes access by multiple applications possible. The DEMS acts as a link between the database and the application programs.

6. File organization determines how rapidly data can be accessed from an information system, and it determines how quickly data can be entered and processed. In sequential file organization, access can only be made in sequential order. Batch processing works well with sequential file organization. Transaction data can be organized in a pre-set order and then be efficiently matched to the sequential order of previously stored data. On-line transaction processing requires direct access to stored data, and the associated file organization must allow for this type of access. If data were stored in sequential fashion in an on-line processing environment, data access would be incredibly slow since the search for a particular data item requires a pass through multiple data items in sequence to reach the desired data.

7. A DBMS facilitates problem solving by eliminating data redundancy, which is the presence of the same data in more than one data file. This condition hinders problem solving because, over time, different groups in the firm may update one version of the duplicated data without changing the others. This creates a situation known as data confusion, wherein data in one system become inconsistent with data in another system. A DBMS also makes the application programmer's work easier by eliminating the need to specify in detail how and where the data are found. Finally, a DBMS provides for more flexible access to data from diverse applications.

REVIEW QUESTION 4-3

1. The primary advantage of the traditional approach is its simplicity compared to the database approach. For stand-alone applications, which do not require the advanced capabilities of database file management, the traditional approach is less expensive and easier to use. An example of such an application is a payroll system, which uses batch processing to update records at the end of each pay period.

   However, when an organization has numerous applications that are related, or when many departments need simultaneous access to the same data, traditional file management tends to create data redundancy, program/data dependence, and data confusion. These conditions lead to high costs, poor performance, and inflexible response to nonstandard information requests. In this situation, database file management makes information easier to access and utilize, reduces complexity, eliminates data redundancy and data confusion, and allows end users to access information without the intervention of technical professionals. Disadvantages of a database approach are that it is costly, requiring a long-term effort to analyze data relationships and design databases, and that implementing a database approach requires organizational discipline and change.

2. The primary shortcomings of traditional file management (data confusion, data redundancy and program/data dependence) are not technical flaws of the system. They are the result of poor planning and mismanagement of data. The advantage of a database approach is that it facilitates planning and data management. This can be done without database management software.

   Data redundancy and data confusion could be eliminated if the various departments in the firm agreed on common definitions for data and agreed to share the data they used in common. Most problems with traditional file management have stemmed from departments developing separate applications and files, one at a time, as the need arose.

   Note that database management software alone can't eliminate the problems of the traditional file environment. One often finds businesses using DBMS to build independent applications rather than shared databases, with the DBMS software being used merely as an improved file access method.