1. Introduction to Computers Chapter 2 §Computers are common in every facet of human activity. §They overcome the shortcomings of conventional radiography systems l computers offer several advantages §1. They process information §2. Store that processed information §3. Retrieve what has been stored §4. Communicate information quickly and accurately

2. §Define computer… §A machine for solving problems. §What is a computer system? §Hardware, software, and computer users. §What is hardware? §The physical components of the machine. §What is software? §The instructions that make the hardware work to solve problems. §Why are computer users important? §They design, develop, and operate the hardware and software.

3. History §Computers date back over 2000 years §Today CT scanners are in their 5th generation §They are classified according to their processing capabilities, storage capacity, size, and cost. §There are four main groups...

4. Supercomputers §Processes data at extremely high speeds §Used in oil exploration §weather forecasts §research (especially in weapons)

5. Mainframes §Capable of rigorous computations at high speeds §Large primary memories and can support many pieces of peripheral equipment §Used in banks §Universities and Colleges §Large businesses and the government

6. Minicomputers §A midlevel computer §performs complex computations while dealing with a high level of input and output from the users §frequently connected to other minicomputers on a network §CT Scanners and MRI Scanners

7. Microcomputers §Personal computers - PCs §Small digital computers such as laptops and notebooks.

8. Binary System §Decimal system has a base of 10 l values are represented as 0 through 9 l any decimal number can be written as a sum of these digits multiplied by a power of 10. §The binary system has a base of 2 l values are represented as 0 and 1

9. Terminology §A binary digit, or a bit, is a single binary number §4 bits = nibble §8 bits = byte §16 bits = word §32 bits = double word §Memory capacity is measured in bytes...

10. §1 thousand bytes = 1 kilobyte KB §1 million bytes = 1 megabyte MB §1 billion bytes = 1 gigabyte GB §1 trillion bytes = 1 terabyte TB

11. Analog to Digital Conversion §The ADC converts the analog signal into a sequence of numbers having finite precision §Converts the analog signal into digital data for processing

12. Digital to Analog Conversion §Outputs digital data that are converted into the analog signals needed to operate analog display devices such as television monitors.