unit 1

Computers are almost everywhere today, but this was not always the case. Here is a brief timeline of computers and computing.

• 1940's-1950's -The first computers began to be built. These were made with very large components and took up entire rooms and generated a lot of heat.
• 1971- The microprocessor was invented, which allowed engineers to design 'small' computers that would fit in a cabinet, but these were not affordable to small businesses or for personal use.
• 1970's- Home computers were sold in kits that had to be assembled. Often they were attached to a television instead of a monitor. These computers were considered to be a hobby.
• 1981- The PC (personal computer) was introduced by IBM (International Business Machines). These were the first computers that were affordable to small business, at about $1500. As a comparison, the cost of a new car was less than $9000.

So many of our daily activities have been changed by computers and smart devices, including:

• Travel

• Shopping

• Education

• Entertainment

  Computers are made of several different components, like the motherboard, mouse, memory, monitor, etc. These parts can be purchased separately, then assembled to make a computer. In this lesson, we will introduce different computer components. Even though laptop and desktop computers may look different, they still have many of the same components.

  Each of the items discussed below are considered hardware. Hardware consists of physical devices, like the ones shown below. Hardware does physical and electronic tasks, like displaying images, storing and retrieving data, printing, connecting to a network. By contrast, software provides the instructions to do these tasks.

Memory	All information and instructions are stored in memory before they are retrieved by the CPU. Memory is the working space for programs that are running on the computer. When the computer is turned off, anything stored in memory is lost. Only information stored on the hard drive is saved.There are two main types of memory: ROM and RAM.ROMThis is 'read only memory.'ROM does not lose data when the power is turned off, but it also does not store new information.The information stored in ROM is instructions to tell the computer what to do when it first starts running.There is only enough ROM in a computer to hold the start-up instructions.RAMThis is 'random access memory.'RAM cards are inserted into the motherboard. If there are empty slots, more memory can be addedIt stores all of the information and instructions for the programs that the computer is currently running. It loses all its data when the power is turned off.Its capacity to store data is measured in bytes. A byte is the smallest piece of information. A megabyte is a million bytes. A gigabyte is a billion bytes. A terabyte is a trillion bytes.When RAM can not hold any more data, some of it is moved to the hard drive. This is known as 'paging'.RAM is much faster at storing and retrieving data than the hard drive, but it is also more expensive.

• Hard drive storage capacity is measured in megabytes (MB), gigabytes (GB), and terabytes (TB).
• The hard drive is slower than memory at storing and retrieving data, but it is cheaper.
• The CPU does not use data directly from the hard drive, it first retrieves it into the RAM.
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Computer hardware would not be very useful by itself. Software contains instructions that tell the hardware what to do. The term 'software' covers a wide range of products. We will explain three categories:

• Operating Systems
• Software Applications
• Computer Languages

Employment in the software industry has grown much faster than most other fields. In this course, we will learn computer programming, one of the essential software skills. Another goal of this course is to help you find out if you like programming.

Kilobyte - Thousands \n Megabyte - Millions \n Gigabyte - Billions \n Terabyte - Trillions

Item Is it a peripheral? Y/N Is it input, output, both, or neither? \n CPU Not peripheral neither \n Hard Drive peripheral storage \n Memory Not peripheral storage \n Monitor peripheral Output, unless it is a touchscreen \n Mouse peripheral input \n Printer peripheral output

Device Does it hold data when \n power is turned off? Y/N \n Is this the quickest to \n access data? \n When memory is too full, does data \n get stored here until it is needed? \n Y/N \n Does this store instruct \n be used when the comp \n on? Y/N \n Hard Drive Y N Y Y \n RAM N Y N N \n ROM Y Y N Y

Characteristic Operating System Computer Language Software Application \n Moves data from hard drive to \n memory? Y / N Y N N \n Used as a basic building block to \n create programs? Y / N N Y N \n Might be used to browse the \n internet? Y / N N N Y \n Schedules time for instructions to \n run on the CPU? Y / N Y N N \n Must be compiled or interpreted to \n run? Y / N N Y N

Which software manages computer resources? operating system,only the OS has direct access to computer resources. All other applications must make requests through the OS.

Where is data stored when the CPU reads it? memory,data is moved to the memory before the CPU reads it. This makes execution faster because the hard drive is much slower to access than memory.

What is a printer considered to be?   peripheral,other examples of peripherals are hard drive, mouse, keyboard, monitor, etc.

What is Java considered to be?computer language, other examples of computer languages are Perl, Python, JavaScript, C++, etc.#

What is Microsoft Windows considered to be?   operating system,other operating systems would be mac)S, Linux, Unix, etc.

What does a programming language do? It is used to create new software applications and operating systems,all apps and operating systems are built using computer languages.

Which device can store data when the power is turned off? hard drive,

How does the computer execute instructions?The CPU executes one instruction at a time, but it does it very quickly,The CPU only reads and executes one instruction at a time. Multi-core processors have more than one CPU, but each CPU can only execute one instruction at a time.

Choose the storage capacity from least to most-kilobyte, megabyte, gigabyte, terabyte

kilo = thousand

mega = million

giga = billion

tera = trillion

Which of the following is true? The CPU is installed in the motherboard,The motherboard provides a secure location to install the CPU and the memory. In addition to that, cables to all of the peripherals are plugged into the motherboard.

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