Tag Archives: systems
File Processing Systems
Even the earliest business computer systems were used to process business records and produce information. They were generally faster and more accurate than equivalent manual systems. These systems stored groups of records in separate files, and so they were called file processing systems. Although file processing systems are a great improvement over manual systems, they do have the following limitations:
Data is separated and isolated.
Data is often duplicated.
Application programs are dependent on file formats.
It is difficult to represent complex objects using file processing systems. Data is separate and isolated. Recall that as the marketing manager you needed to relate sales data to customer data. Somehow you need to extract data from both the CUSTOMER and ORDER files and combine it into a single file for processing. To do this, computer programmers determine which parts of each of the files are needed. Then they determine how the files are related to one another, and finally they coordinate the processing of the files so the correct data is extracted. This data is then used to produce the information. Imagine the problems of extracting data from ten or fifteen files instead of just two! Data is often duplicated. In the record club example, a member’s name, address, and membership number are stored in both files. Although this duplicate data wastes a small amount of file space, that is not the most serious problem with duplicate data. The major problem concerns data integrity. A collection of data has integrity if the data is logically consistent. This means, in part, that duplicated data items agree with one another. Poor data integrity often develops in file processing systems. If a member were to change his or her name or address, then all files containing that data need to be updated. The danger lies in the risk that all files might not be updated, causing discrepancies between the files. Data integrity problems are serious. If data items differ, inconsistent results will be produced. A report from one application might disagree with a report from another application. At least one of them will be incorrect, but who can tell which one? When this occurs, the credibility of the stored data comes into question. Application programs are dependent on file formats. In file processing systems, the physical formats of files and records are entered in the application programs that process the files. In COBOL, for example, file formats are written in the DATA DIVISION. The problem with this arrangement is that changes in file formats result in program updates. For example, if the Customer record were modified to expand the ZIP Code field from five to nine digits, all programs that use the Customer record need to be modified, even if they do not use the ZIP Code field. There might be twenty programs that process the CUSTOMER file. A change like this one means that a programmer needs to identify all the affected programs, then modify and retest them. This is both time consuming and error-prone. It is also very frustrating to have to modify programs that do not even use the field whose format changed. It is difficult to represent complex objects using file processing systems. This last weakness of file processing systems may seem a bit theoretical, but it is an important shortcoming.
Introduction to Database Processing and Information
Database processing is one of the most important courses in the information systems curriculum. There are several reasons for this. First, databases can store large volumes of corporate operational data. Such databases become the heart of many transaction processing applications, such as order entry, inventory control, and general ledger accounting. Due to the advantages of database systems over file processing systems, many companies have converted (or are converting) their older file processing systems to database systems. Second, databases can be queried on an ad hoc basis, making them the foundation for decision-support systems (DSS). Data stored in a database can be readily accessed and processed. Consequently, users can get answers to their questions much faster if the data is stored in a database than they would if it were stored in files. Further, database query languages allow users to be more self-sufficient. Users often obtain answers to their questions without the assistance of an information systems professional. Third, databases can be implemented on computers of all sizes, making them feasible for almost any business or organization. Thus, the likelihood that you will employ database processing during your information systems or business career is almost certain. But perhaps the most fundamental reason for studying database technology is that it facilitates the production of information.
Information
The word information comes from the Latin word informare, which means “to build form” or “to give structure.” Information systems build structures from data by processing it to reveal patterns, trends, and tendencies. These patterns, trends, and so forth are the information that users need in order to perform their jobs. If we did not derive information from the huge volumes of facts we store in our computers (the data), then users would be overwhelmed with details, floundering about to find the knowledge they need. They would drown in a sea of facts. People strive to make order in their world. Think about the first time you endured the add/drop process during class registration (or the first time you went to an airport, or the first time you did anything new). If your college is like most, the room was large, hot, noisy, and chaotic. People were moving all around you and you didn’t know quite what to do. Probably your anxiety level was high as you tried to make any meaning out of the scene before you. Unconsciously, you gathered data through sight and sound, related this data to prior knowledge (such as knowing how people line up and wait their turns or take numbers and wait to be called), compared this new data to your goal (dropping a course, for example), and decided on a course of action (to get into the line marked “DROP COURSE”). The key element in this scenario is the processing of your perceptions. As you gathered data by examining the room, you built patterns and structures in your mind and tried to relate them to structures you already had. You looked for clues in people’s behavior. You might have asked somebody for help. If so, your plea was a request for information. You wanted someone who had already processed the scene and built patterns and structures to tell you what they were. As you gained information about the add/drop process, your uncertainty decreased. When you entered the room, you did not even know in which direction to turn. Once you knew which line to join, you became more sure of yourself. Information reduced your uncertainty. Computer systems provide a similar function for users. One of the main reasons for information systems is to reduce the user’s uncertainty.
Introduction to Database Processing and Information
Database processing is one of the most important courses in the information systems curriculum. There are several reasons for this. First, databases can store large volumes of corporate operational data. Such databases become the heart of many transaction processing applications, such as order entry, inventory control, and general ledger accounting. Due to the advantages of database systems over file processing systems, many companies have converted (or are converting) their older file processing systems to database systems. Second, databases can be queried on an ad hoc basis, making them the foundation for decision-support systems (DSS). Data stored in a database can be readily accessed and processed. Consequently, users can get answers to their questions much faster if the data is stored in a database than they would if it were stored in files. Further, database query languages allow users to be more self-sufficient. Users often obtain answers to their questions without the assistance of an information systems professional. Third, databases can be implemented on computers of all sizes, making them feasible for almost any business or organization. Thus, the likelihood that you will employ database processing during your information systems or business career is almost certain. But perhaps the most fundamental reason for studying database technology is that it facilitates the production of information.
Information
The word information comes from the Latin word informare, which means “to build form” or “to give structure.” Information systems build structures from data by processing it to reveal patterns, trends, and tendencies. These patterns, trends, and so forth are the information that users need in order to perform their jobs. If we did not derive information from the huge volumes of facts we store in our computers (the data), then users would be overwhelmed with details, floundering about to find the knowledge they need. They would drown in a sea of facts. People strive to make order in their world. Think about the first time you endured the add/drop process during class registration (or the first time you went to an airport, or the first time you did anything new). If your college is like most, the room was large, hot, noisy, and chaotic. People were moving all around you and you didn’t know quite what to do. Probably your anxiety level was high as you tried to make any meaning out of the scene before you. Unconsciously, you gathered data through sight and sound, related this data to prior knowledge (such as knowing how people line up and wait their turns or take numbers and wait to be called), compared this new data to your goal (dropping a course, for example), and decided on a course of action (to get into the line marked “DROP COURSE”). The key element in this scenario is the processing of your perceptions. As you gathered data by examining the room, you built patterns and structures in your mind and tried to relate them to structures you already had. You looked for clues in people’s behavior. You might have asked somebody for help. If so, your plea was a request for information. You wanted someone who had already processed the scene and built patterns and structures to tell you what they were. As you gained information about the add/drop process, your uncertainty decreased. When you entered the room, you did not even know in which direction to turn. Once you knew which line to join, you became more sure of yourself. Information reduced your uncertainty. Computer systems provide a similar function for users. One of the main reasons for information systems is to reduce the user’s uncertainty.