Computer Peripheral Devices and Memory Concepts

### Computer Peripheral Devices

- CPU is not a peripheral device.  Peripheral devices are input/output (I/O) devices.
- Keyboard, monitor, and mouse are peripheral devices.


### System Unit Components

- A port is a place that allows transfer of data between different devices and a computer.


### Computer Memory

- ROM (Read-Only Memory) is a type of memory in which users cannot write new information or instruction.
- RAM does allow users to write new info or instructions.


### Data Representation

- A group of 8 bits is equal to a byte.
- A megabyte is equal to 1,024,000 bytes.


### Input/Output (I/O)

- Device drivers allow input/output devices to communicate with the rest of the computer system.


### Memory Types

- Primary memory consists of primary and secondary memory.
- CD is a non-erasable disk for storing audio information.


### Functions of the Output Unit

- The output unit converts the data entered by the user to a computer-understandable format.
- The output unit makes the computer results easy for the user to understand.
- The output unit does not supply data and instructions to the computer for further processing.


### Data Types

- Data, in computer terminology, is the raw input used by a computer system for processing to generate output of the form of information.


### Computer Characteristics

- Computers are fast, and accurate, but not intelligent.


### Memory and Storage

- Memory is the space where data is held temporarily.
- Storage is where data is held permanently when not needed.


### Memory Capacity

- Memory capacity is measured in megabytes.


### CPU Chip

- L1 cache is built into the CPU chip.


### Processor Speed

- Processor speed is measured in megahertz.


### Display Properties

- Dot pitch refers to the distance between pixels on a screen.


### Screen Elements

- An icon is a pictorial symbol that represents a computer activity on a screen.


### Copy Operations

- Duplicating a file in another location is often called copying.


### Operating System

- A single-tasking operating system can only run one program at a time.
- Multitasking operating systems allow more than one program to run at a time.
- Windows 2000 is an example of a preemptive multitasking operating system.
- Booting is the process of loading an operating system.
- The operating system's primary program is a kernel.
- A computer operating environment is also known as a shell.
- The GUI is a graphical user interface.


### Storage Devices

- Optical disks are a medium that's used for high capacity secondary storage.
- Laser-beam technology is used to read/write data on optical disks.
- The storage capacity of an optical disk is determined by multiplying the number of sectors by the number of bytes per sector.
- Rotational speed of a disk varies inversely with its radius.
- Sectors on a disk have fixed size—not increasing or decreasing in size.
- Access times for optical disks generally fall between 100 and 300 milliseconds.


### Input/Output Devices

- A scanner is a device that converts printed paper into digital data.


### Data Representation

- A bit is the smallest possible unit of information.
- A byte is 8 bits.
- A kilobyte (KB) is equal to 1,024 bytes.


### Data Types

- Data that is processed by computers is converted into Information
- Instructions are given to the CPU which results in changes that occur to data.
- A computer follows steps to process data into information.


### Software Types

- Packaged software is software that's widely available, usually for sale or download.
- Custom software may include special programming functions and or code written specifically for business users.
- Vertical market software provides software solutions for industries.
- Groupware software is a program used for collaborative work.
- The operating system is the fundamental software.


### Special Types of Software

- Public domain programs are usually free of charge and not copyrighted.


### Data and Program Storage

- Additional data and instructions that are not immediately needed for processing are stored in secondary storage.


### Computer Literacy

- Knowing what computers are and how they work are key elements in being computer literate.


### Components of a CPU

- **Control Unit (CU):**  Direct the system to carry out stored programs.
- **Arithmetic Logic Unit (ALU):** Performs arithmetic operations (add, subtract, multiply, divide) and logical operations (comparing, etc.)