Introduction to Computer Systems
Review these notes. For maximum benefit, go through these notes interactively, thinking about and answering the questions at the bottom of each page. These notes are an experiment in applying the "programmed learning" method to web-based computer aided instruction. The subject is Java Programming for beginning programmers. The content is intended to start beginning programmers out on the track to professional-level programming and reinforce learning by providing abundant feedback. Java is a programming language that is used often in professional practice.
Software
Answer:
Does the computer controlling an automobile engine have:
- Input devices? Yes — various sensors throughout the car deliver data to the computer.
- Output devices? Yes — various actuators (that perform actions) are controlled by the computer.
- Main storage? Yes — ROM holds the program and there must be enough RAM to hold the current data and results.
- Secondary storage? No — Hard disks do not hold up well next to a car engine.
Software
Computer software consists of both programs and data. Programs consist of instructions for the processor. Data can be any information that a program needs: character data, numerical data, image data, audio data, and countless other types. The distinction between programs and data is not as clear-cut as you might think, however.
Fundamental Idea: Both programs and data are saved in computer memory in the same way. The electronics of computer memory (both main memory and secondary memory) make no distinction between programs and data.
The insight that both programs and data can be saved using the same electronic methods is an important concept in computer science. Computer systems use memory for either programs or data, as needed.
Question 11:
Which of the following can be saved on a disk?
- A game program
- Accounting data (numbers)
- Audio data
- Graphics data
- Digital photographs
- Video data