1 / 18

Lecture 1

Lecture 1. Computers and Society – Past and Present. Define the term computer. Here are two definitions: A computer is a device or set of devices which works under the control of a stored program (which can be changed), automatically accepting and processing data to produce information.

barb
Download Presentation

Lecture 1

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Lecture 1 Computers and Society – Past and Present

  2. Define the term computer Here are two definitions: • A computer is a device or set of devices which works under the control of a stored program (which can be changed), automatically accepting and processing data to produce information. • A computer is an electronic device, operating under the control of instructions stored in its own memory, that can accept data, process the data according to specified rules, produce results, and store the results for future use.

  3. Types of Computers • There are three ways in which computers process signals: • Anolog • Digital • Hybrid Note: For this course, it is important not to confuse types of computers with categories of computers (e.g. micros, mini, mainframe etc to be discussed later).

  4. Types of computers (continued) • Data is processed in one of two ways: analog or digital. People generally process analog data (i.e. continuous wave patterns). The sight and sound of a motor vehicle transmits to your ears and eyes as sound and light waves, or smooth up-and-down patterns (see next slide). A computer, by contrast, is digital, which means computers process data in two discrete (measurable) sates: positive (on, or 1) and non-positive (off, or 0).

  5. Types of computers (continued)

  6. Types of computers (continued) • The 1 and 0 represent the two digits used by the binary number system. While this system is at the heart of digital computing, binary digital impulses appear as long strings of 1s and 0s. • If sound and light waves are analog and a computer is digital, how does a computer record audio clips, play music or show a movie? How can a digital computer use an analog telephone line to dial up to access the Internet?

  7. Types of computers (continued) • The key lies in analog-to-digital conversions. For example, the computer’s sound card allows you to record sounds and playback sounds. The sound card performs these conversions to record a digital audio clip of your analog voice. The sound card connects to the microphone, which is an analog input source. The diaphragm in the microphone converts the analog sound waves into an electrical signal.

  8. Types of computers (continued) • This signal flows to the sound card’s analog-to-digital converter (ADC), which converts the signal into digital data. The digital data flows to the digital signal processor (DSP), compressing the data to save space. Finally, the compressed data is stored in an audio file format. To play a recorded sound, the computer reverses the process. The processor retrieves and sends the digital data to the DSP to be decompressed.

  9. Types of computers (continued) • The DSP sends the decompressed digital data to the sound card’s digital-to-analog converter (DAC), which converts the digital data back to an analog voltage for output via a speaker or headset. In other words, a DAC takes that long binary number string of 1s and 0s and turns it into an electronic signal that the sound output devices can decode and use.

  10. Don’t Panic! • The previous slides could be simplified to say computers can process digital or analog data and if the computer is capable to processing both then it is called a hybrid computer.

  11. Brief History of Computers • The very first computer was used in 3000 B.C. and was called the abacus.

  12. Generation of Computers There are four generation of computers: • First generation (1940s) – consisted of vacuum tubes. • Second generation – Transistorsreplaced vacuum tubes. • Third generation – utilised Integrated Circuits (IC) • Fourth generation – utilised Very Large Scale Integrated Circuits (VLSIC)

  13. Vacuum Tube

  14. Transistors

  15. Integrated Circuits

  16. Categories of Computers Discovering Computers 2010: Living in a Digital WorldChapter 1 Page 19

  17. Computers in Industry and Sectors • We will switch to Chapter 1 and discuss the rest of lecture 1.

More Related