Please read the attached files.
This assignments contains article from chapter 1,2,3,9/appendix B
Chapter 1 – Defining Information Technology – Fluency with Information Technology
Chapter 2 – Exploring the Human-Computer Interface – Fluency with Information Technology
Chapter 3 – The Basics of Networking – Fluency with Information Technology
Chapter 9 – Principles of Computer Operations – Fluency with Information Technology (7th Edition)
Appendix B – Integrated Circuits and Semiconductors – Fluency with Information Technology (7th Edition)
I’m attaching text book but that is 6th edition all chapters are good except the appendix in 6th edition. If you have 7th edition you can see from there or use the summary for appeni B I’m writing below.
Thank you
Learning Objectives
Explain that modern software is written in a language that makes use of familiar terms and operations.
Summarize what the Fetch/Execute Cycle is and how it functions.
Describe how the Fetch/Execute Cycle is hardwired into the control subsystem and how that relates to the processor.
Explain how memory functions and what it is composed of.
Recall the function of the ALU.
Explain how the input and output units relate to peripheral devices.
Recall that machine instructions refer to the data indirectly and describe how that allows for different computations.
Explain that programmers use sophisticated programming languages in the creation of complex operating systems and applications software.
Explain the importance of integrated circuits (ICs) to modern computing and how integration and photolithography allow ICs to be made cheaply and reliably.
Explain the importance of semiconductors and how they control electrical currents to carry out computer processing.
Glossary Terms
Make sure you read and study the definitions for each of these terms provided in the back of your text in the Glossary section. The definitions are often more detailed and explanatory than what is in the chapter text which provides further understanding of the terms and concepts. These definitions are also included in the quizzes and tests.
apps
assembler
assembly code
assembly language
binary
binary code
central processor
channel
compiling
computer
core
CPU (central processing unit)
device driver
execution
Fetch/Execute Cycle
field effect
field effect transistor
gate
indirect reference
integrated circuit (IC)
integration
MOS (metal oxide semiconductor)
microprocessor
object code
operand
operating system (OS)
peripherals
photolithography
photoresist
pipeline
processor
program counter
RAM (random access memory)
semiconductor
source code
An Overview of Computers
Computers are used everywhere, all the time, as there is a continuous need for computation.
Computers are laptops, cameras, tablets, MP3 players, desktops, TVs, and basically most every electronic device.
Computer Terminology
Processor is what follows the program’s instructions.
Operating System is the program that carries out most common operations and is what makes the computer useful to us.
Software are applications or apps.
Instructions tell the processor what to do.
Fetch/Execute Cycle is what executes the instructions.
Memory is what stores the data.
Hardware are the physical parts of the computer.
Software Deeper Look
A new app is just a long sequence of bits.
Programmers created the bits but did not actually type them out themselves.
A series of instructions expressing an algorithm is a program.
There are not a lot of lines of instruction with a few symbols in each.
A typo of any size can cause a bug.
Without specialized training it is very hard to understand a program’s meaning.
Software Layers
System software is configured in layers.
Every layer utilizes services from the layer below.
Every layer also supplies services to the layer above.
There is a shared effort where new programs reuse work that already exists.
A feature can be used for numerous applications once it is written.
When there is a bug or a need for improvement, changes are done in only one place.
Instruction Execution Engine and Fetch/Execute Cycle
Instructions are constantly being executed by a computer and repeated in a ceaseless sequence.
This is done through a series of operations known as the Fetch/Execute Cycle.
Instruction Fetch (IF) – obtain instruction.
Instruction Decode (ID) – determine what needs to be done.
Data Fetch (DF) – obtain necessary data.
Instruction Execute (EX) – carry out the instruction.
Result Return (RR) – result is saved.
Repeat process at a rate of billions per second.
Computer Anatomy
All computers have only five basic parts or subsystems.
Memory
Control unit
Arithmetic/Logic Unit (ALU)
Input unit
Output unit
Memory Subsystem
Memory contains the program both while it is running and the data that the program operates from.
The organization of memory is done through a sequence of labeled containers known as locations which are each composed of 1 byte or 8 bits.
The memory locations each have an address which represents that location’s place in the sequence.
Each memory location records or stores values which are the contents of the containers.
There is a fixed amount of capacity or limited size in each memory location as the containers can only hold so much.
Memory is Composed of Bytes
Each memory location is 1 byte which can store one ASCII character or a number that is less than 256.
Four bytes, or a block, are used as one unit and are often called memory words.
Random Access Memory (RAM)
Memory on a computer is called random access memory or RAM.
Computer’s can access memory locations in any order or randomly, hence the name.
Megabytes or gigabytes measure the amount of RAM.
Programs and data take a lot of space and therefore need a lot of memory.
Control Unit Subsystem
The Fetch/Execute Cycle takes place in the control unit of a computer.
The control unit fetches the instructions and then carries out all other functions of the Fetch/Execute Cycle.
Arithmetic/Logic Unit (ALU) Subsystem
Conducts the mathematically based operations.
ALU circuits can add two numbers, multiply them, compare them and so on.
Each machine instruction is carried out with a separate circuit.
Circuits use logic gates which are simpler circuits that conduct operations like OR and AND.
Input and Output Units Subsystem
Information moves in and out of a computer through the wires and circuits in these components.
A computer that does not have input or output serves no purpose to us.
Peripherals
The computer is connected through the input/output (I/O) ports by peripherals.
Peripherals supply input or receive output.
They are not considered to be part of the processor.
Peripherals are gadgets that serve a specific purpose that either encodes or decodes information traveling to and from the processor.
Operating the Physical Part of the System, Peripherals
Keystrokes from the keyboard are turned into binary for the computer to understand.
The computer’s memory is decoded by monitors to display information in a way we can read it.
Peripherals can also serve to store information and are used by computers for both input and output.
Examples are USB memory sticks or hard disks and drives.
Device Drivers for Peripherals
Only basic translation to or from binary is done by peripherals.
The computer must provide additional information to make the peripheral operate in a useful way.
Peripherals all have software called device drivers to give the input and output of the peripheral meaning and to dictate its behavior.
Machine Instructions
Instructions that the computer follows is a lot simpler than what is typed by programmers.
As an example, ADD 4000, 2000, 2080
The instructions command the computer to add the numbers stored in the memory locations 2000 and 2080 then save that total in the memory location 4000.
The memory address is what is encoded by the computer instructions and not the numbers themselves. This is called indirect reference.
The Program Counter of the PC
The next instruction a computer is to execute is determined by using that instruction’s address.
The address, called the program counter or PC, is used by the computer to track the next instruction.
It is assumed that the next instruction is the next one in the sequence.
Instructions use 4 bytes of memory which means the next instruction in the sequence is found at memory address PC + 4 and the processor simply increases the PC by 4 to get to it.
Branching and Jumping in the Program Counter
Instructions are not always in a strict sequence.
The instruction could have a memory location, or address, that it should go to next.
The PC, instead of automatically going PC + 4, changes and the computer jumps or branches to the location given to continue its execution process.
Instruction Fetch Example: ADD 4000, 2000, 2080
The instruction execution starts with the address given by the PC (PC 800) being moved from memory to the control unit.
Instruction bits are then placed in the CU in the decoder circuit.
The PC has fetched the instruction and is now prepared to fetch the next instruction.
Instruction Decode Example: ADD 4000, 2000, 2080
The next operation makes use of the Arithematic/Logic Unit (ALU).
The memory address of the instruction’s data, called source operands, is found by the decoder.
Two data values are usually stored in the memory for instructions (using ADD for example) which means most instructions contain addresses for two source operands.
In the next step the addresses are sent to the circuit that fetches them from the memory.
The destination address for the Result Return step is located by the decoder and that address is placed in the RR circuit.
The operation that the ALU will perform is determined by the decoder which also sets the ALU up.
Data Fetch Example: ADD 4000, 2000, 2080
The data needed to carry out the operation is pulled from memory.
Memory location bits are copied to the ALU circuitry.
The data values are not destroyed and instead remain in the memory.
Instruction Execute Example: ADD 4000, 2000, 2080
The addition circuit adds the two source operands together to get their sum and carry out the ADD instruction.
The sum is retained in the ALU circuitry.
The actual computation is performed here.
Result Return Example: ADD 4000, 2000, 2080
The result of the Instruction Execute is received from the Result Return and placed in the memory location stated by the destination address.
The cycle begins again after the result is stored.
Numerous and Quickly Done Operations
Computers only understand a limited number of instructions. The controller’s decoder hardware recognizes, and the ALU performs, only about 100 different instructions, but there is a lot of duplication.
Operations like ADD are part of only about 20 total operations.
Anything a computer is programmed to do has to make use of a combination of these primitive and hardwired instructions.
Speed is what allows computers to be useful to use by executing these instructions many times per second.
The computer’s clock determines the rate and is measured in megahertz, or millions (mega) of cycles per second (hertz).
A 1GHz clock takes only one billionth of a second, or nanosecond, to run the Fetch/Execute Cycle between one tick on the clock and the next.
Translation
Source code written by a programmer looks like this: Opacity += 0.02
The processor needs bits known as object code, binary code or binary.
Source code is first translated into assembly code then into binary.
Assembly Language
Simple programming language uses words instead of Os and 1s: ADD Opacity, TwoCths, Opacity
The source code is compiled by the compiler to convert it into assembly.
Compilers
A computer program that translates a computer program into assembler language is called a compiler.
Every compiled language needs its own compiler.
Yet another program, the assembler, is used to convert the assembly language to machine language.
Integrated Circuits and Semiconductors
Computers cannot function in the way they do without the use of two critical pieces of technology; integrated circuits (ICs) and semiconductors.
Integrated circuits allow for complex devices to be made in a very reliable and inexpensive way.
Semiconductors control electrical currents efficiently which includes controlling signals that are critical for computer processing.
Properties of ICs
Miniaturization allows computer clocks to run faster.
Integration allows all parts of a circuit to be made together.
Photolithography allows chips to be printed cheaply and efficiently.
Miniaturization
The ability to make chips smaller allows computers to run at speeds in the GHz.
This is because it takes time for an electrical signal to travel its path.
The less distance the signal must travel means the quicker the operation can be completed.
GHz speeds mean that each step of the Fetch/Execute cycle will occur in less than one nanosecond which could not be possible if chips or computer parts were bigger.
Integration
Integration was a monumental achievement that changed the way computers could be made.
Prior to integration, computers were built with separate parts that had to be connected as the computer was assembled which was a time consuming and tedious process.
Computers capable of serious work would then have many thousands or even millions of parts requiring manufacture and assembly for each computer and would make those computers very rare and error prone.
The concept that integration brings is the ability to make all the parts in single, multistep process using similar materials to create one monolithic part for the entire system.
All parts of the circuit are placed side by side in silicon allowing the connecting wires to be put into place and easily connected as part of the assembling process instead of needing to be individually connected by soldering wires together.
This not only saved space but also greatly increased speed and reliability.
Photolithography
A printing process that works by making chips as a series of layers like a sandwich.
Each layer is laid down with the transistors, capacitors, and wires that make up chips.
Wires require separation so they are laid down apart from each other in the chip.
Each layer is covered by a light-sensitive material called photoresist and then a mask is placed over it.
The mask is patterned exactly like the parts being constructed.
The light sensitive photoresist is then exposed to UV light causing the parts that are not under the mask to harden and the parts not under the mask can be washed away leaving the desired pattern.
Hot gases are used to etch away the parts that are exposed and after removing the rest of the photoresist only the mask pattern and new features are left.
This process allows the chips to be as complicated as they need to be without a change in the cost since the process is exactly the same for a simple or a very complicated chip.
Properties of Semiconductors
Field effect is the process by which electrically charged objects can have an effect on another object without touching it and is very useful in semiconductors.
Silicon is vital to how semiconductors are able to conduct electricity.
Field effect transistors use silicon to control electrical currents.
Field Effect
Objects possess positive and negative charges.
Positive charges repel other positive charges but attract negative ones and vice versa without touching called the field effect.
Silicon is a Semiconductor
Silicon possesses the ability to conduct electricity some of the time making it a semiconductor.
When placed in the middle of a wire the silicon can conduct a signal taking it from one part of the wire to the next or not conduct causing the signal to stop.
Being able to control whether the silicon conducts or not makes it possible to build a computer.
Field Effect Transistors
Control the ability of silicon to conduct electricity or not.
A channel is created between two points in a wire by inserting a gap made of neutral silicon as well as spots of doped silicon at the ends of each wire.
A gate is located above the channel composed of a metal wire and is separated from the channel silicon by a thin layer of glass which serves as an insulator.
When the gate is positively charged it attracts electrons from the neutral silicon below which connects the two wires. When it is not charged there is no connection.
This process has no moving parts making it easy to assemble and operate and both reliability and durability are greatly increased.
2, 3, 9/Appendix B,,
