File organization

1. An organized collection of data is a database.

2. The advantage of a computer database is flexibility in organizing, displaying and printing information.

3. Databases are stored on a disk.

4. Disks can be optical or magnetic.

5. Usually one record is displayed on the screen at a time.

6. A field is an item of information on the computer record.

7. A field consists of the field name and the field data.

8. There are three main types of file organization, that is, serial, sequential and random.

9. With a serial file, the records do not follow each other in any particular order.

10. For adding a record to a serial file it can be added to the end of the file.

11. With a sequential file, the records follow in certain sequence.

12. With random files, records are not stored in any order; they are found by means of the disk surface map.

13. You can access directly both sequential and random access files.

File Manipulation

1. With a computerized filing system, it is easy to sort, search, merge and update files.

2. File updating means brining a file up-to-date.

3. Processes involved in updating are insertions, deletions, amendments.

4. Sorting can be performed according to one or several fields.

5. Merging is combining files.

6. Merging is useful when we want to divide the work.

7. Databases with the same structure are merged to produce a complete database.

8. File interrogation is getting information from a file.

9. To search for data, you must first select the required fields.

10. The computer finds all the records which match the field.

11. You can analyze data of a database.

12. You can produce bar charts, pie charts and line graphs.

Graphics

1. Graphics include all types of artwork.

2. Using a graphics package we can produce diagrams, bitmap images, photographs, graphs and charts.

3. A graphic file can represent an image as a bit map or as vector graphics.

4. In a bit map each pixel on the screen is represented as a single bit of information in a file.

5. Additional bits will need to be stored if the pixel is in colour.

6. Bitmapped images are difficult to change because they are altered a pixel at a time.

7. With bitmapped graphics, if the image is enlarged, the pixels move further apart.

8. So enlarged bitmapped image will look grainy.

9. With vector graphics, lines have a vector format.

10. The main advantage of vector graphics is that it is easy to change without the loss of resolution.

11. When a vector graphics image is enlarged, the number of pixels increases in proportion but the resolution stays the same.

Robots

1. An industrial robot is a reprogrammable multi-functional manipulator designed to perform a variety of tasks.

2. An industrial robot consists of three parts: manipulator, power supply and controlling computer.

3. Manipulator is the moving part of a robot.

4. Power supply of powerful robots is the hydraulic system with a compressor.

5. Lightweight robots use electric power supply.

6. A controlling computer is a low current device, so it needs an interface to protect it from high currents of motors and solenoids.

7. .Robots navigate themselves along the tracks on the floor.

8. An ultrasonic detector emits an infrared beam.

9. If anything gets on the way of the beam, the robot stops.

10. The power supply for moving robots is a rechargeable battery.