Chapter 1 - Sections 1.1 and 1.2

Without Software

A computer can do nothing...

A Programer of Software Developer

A person with the training and skills necessary to design, create, and test computer programs.

Program

A set of instructions stored in the computer's memory that a computer follows to perform a task.

Output Device

Any information that the computer needs to send to the outside world is released from the computer sends to then formats and presents through these.

Binary digit (inside RAM)

Bits

Without it a computer could not run software

CPU

The typical components of a computer:

CPU, Main memory (RAM), Secondary Storage Devices, Input Devices, Output Devices

Two Parts of the CPU

Control Unit & the Arithmetic and Logic Unit (ALU)

The Control Unit (in CPU)

Coordinates all of the computer's operations. Determines where to get the next instruction. Regulates the other major components of the computer with control signals.

CPU process when a computer is running a program:

Fetch / Decode / Execute cycle

The CPU's Job

Fetch instructions, follow the instructions, and produce some result.

Optical Devices (Secondary Storage)

Include CD (compact disc) and DVD (digital versatile disc) drives. Data is not encoded magnetically, but is encoded as a serial of pits on the disc surface. A laser in the drive will detect the pits and read the encoded data

RAM is volatile because

It is only used for temporary storage while a program is running. The contents of the RAM stored inside of your computer on small chips are erased when the computer is turned off.

Common Types of Output Devices

Monitors, printers, and speakers. CPU sends information to Disk drives, USB drives, and CD/DVD recorders to be saved, so they can also be thought of as...

Operating Systems (system software)

Most fundamental set of programs on a computer. It controls the internal operations of the computer's hardware, manages all the devices connected to the computer, allows data to be saved to and retrieved from storage devices and allows other programs to run on the computer.

One byte can store: (inside RAM)

One letter of the alphabet or a small number. (Most computers today have millions or billions of bytes)

Types of programs included in system software

Operating systems, Utility Programs, and Software Development Tools.

Utility Programs (system software)

Performs a specialized task that enhances the computer's operation or safeguards data. Examples include virus scanners, file-compression programs, and data-backup programs.

The Arithmetic and Logic Unit (ALU) (in CPU)

Performs mathematical Operations in the CPU.

USB (universal serial bus) Drive (Secondary Storage)

Plugs into a computer's corresponding port and appears to the system as a disk drive.. They use flash memory to store data.

Software

Programs are commonly referred to as:

Application Software

Programs that people normally spend most of their time running on their computers that make a computer useful for everyday tasks. Examples include the Microsoft Office programs, web browsers, e-mail programs, and game programs.

The Central Processing Unit (CPU)

Runs, or executes, computer programs. Makes the computer perform tasks that a program tells it to do.

Bits (inside RAM)

Smaller then a byte. Each byte is composed of 8 of these smaller storage locations.

Programs are (storage)

Stored in secondary memory and loaded into main memory as needed.

Reason behind the name of Random Access Memory

The CPU is quickly able to access data stored at any random location in the RAM.

Fetch (in CPU)

The CPU's control unit fetches, from the main memory, the next instruction in the sequence of program instructions.

An address

The assigned unique number inside of RAM in order of lowest to highest that a byte is identified as. These are thought of as post office boxes or storage cells for each bytes of data.

Main Memory (RAM) Random Access Memory

The computers work area where programs and data are stored in the computer while programs are running.

Input Device

The device that collects the information and sends it to the computer.

Decode (in CPU)

The instruction of encoded in the form of a number. The control unit decodes the instruction and generates an electronic signal.

Disk Drive (Secondary Storage)

The most common type of secondary storage. Stores data by magnetically encoding it onto a circular disk mounted inside of the computers case.

Bytes (inside RAM)

The name of the tiny storage locations inside of a computer's memory.

Hardware

The physical components that a computer is made of.

System software

The programs that control and manage the basic operations of a computer.

Execute (in CPU)

The signal is routed to the appropriate component of the computer, such as the ALU, a disk drive, or some other device. The signal causes the component to perform an operation.

Software Development Tools (system software)

The software tools that programmers use to create, modify, and test software. Examples include compilers and integrated development environments.

Secondary Storage

The type of memory that can hold data for long periods of time, even when the computer is turned off with no power.

The ENIAC

The world's first programmable electronic computer, built in 1945 for the U.S Army.

Bits are thought of as switches because: (inside RAM)

They are tiny electrical components that can hold either a positive or negative charge . The thought of On is positive and Off is Negative.

Microprocessors

Today's small CPU chips

External disk drives (Secondary Storage)

Used to create backup copies of important information or move information from computer to computer. Includes floppy disk drives, USB drives, CD, and DVD drives.

Common types of Input Devices

keyboard, mouse, scanner, digital camera, and microphone. Programs are retrieved from Disk drives, CD/DVD drives, and USB drives and loaded into the computer's memory, so these can also be thought of as ...

Two general categories of software

system and application