Hardware CSCE 101 Electricity: Voltage

• Gate: A signal enters the gate at a certain voltage. The gate performs operations on it, and sends it out was a new signal.

• The signals voltage will either be between 0-2 (binary 0), or 2-5 (binary 1) • So Binary data is travelling around our as a voltage signal Gates

• There are different types of gates, to accomplish different types of logic. • NOT Gate, which negates the signal • AND Gate, which takes two signals and combines them… Basic Logic Operators • AND • OR Binary • XOR • NOT Unary

Y = a•b, Y is 1 if and only if a=b=1 • Y = a+b, Y is 1 if either a=1 or b=1 • Y = a’, Y is 1 if a=0 • Y = a⊕​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​ b, Y is 0 if both a and b are same, 1 if they are different Basic Logic Operators (cont.)

• 1-bit logic AND resembles binary multiplication: 0 • 0 = 0, 0 • 1 = 0, 1 • 0 = 0, 1 • 1 = 1 • 1-bit logic OR resembles binary addition, except for one operation: 0 + 0 = 0, 0 + 1 = 1,

1 + 0 = 1, 1 + 1 = 1 (≠ 102)

2018.09.16 Boolean Algebra PJF - 5 Truth Tables for logic operators

Truth table: tabular form that uniguely represents the relationship between the variables of a function and its output

2-Input AND ● 2-Input OR A B Y=A•B A B Y=A+B ● NOT 0 0 0 0 0 0 A Y=A’ 0 1 0 0 1 1 1 0 0 1 0 1 0 1 1 1 1 1 1 1 1 0

2018.09.16 Boolean Algebra PJF - 6 Logic Gates

• Logic gates are abstractions of electronic circuit components that operate on one or more input signals to produce an output signal.

● 2-Input AND ● 2-Input OR ● NOT (Inverter) A Y A Y A Y B B

Y = Y = Y = A•B A+B A’

2018.09.16 Boolean Algebra PJF - 7 Logic Gates 1 Bit Addition

• Let A and B are two inputs to be added

● SUM = A ⊕B

● CARRY = A•B

2018.09.16 Boolean Algebra PJF - 9 Integrated Circuits

• An integrated circuit is a piece of silicon on which multiple gates have been embedded. (CSI) • The integrated circuit consists of pins which are the input and output to gates.

• The CPU () is an advanced integrated circuit with a large number of pins Computer Functions

Input Process Output Store Computer Functions

• Input: Gathers data often from user entry • Process: Takes data performs instructions on it, to change it into the desired information • Storage: Saves data for use later • Output: Displays data in a human readable form ● Programmable data model

● A program is a set of instructions that tells the computer what to do with data.

● A program is a set of instructions written in a computer language.

● The output data depend on the combination of two factors: the input data and the program. ● Same program, different data ● Same data,

● different

● programs Measurement Units

Since we can have large pieces of data we need ways to represent large binary numbers

Unit Size Bit (0 or 1)

Byte 8 bits

Kilobyte (KB) 210 bytes = 1024 bytes Megabyte (MB) 210 KB = about 1 million bytes

Gigabyte (GB) 210 MB = about 1 billion bytes

Terabytes (TB) 210 GB = about 1 trillion bytes Petabyte (PB) 210 PB = about quadrillion bytes

• Hardware refers to the physical parts of the computer that can be touched. • Examples: – mouse – keyboard – graphics card – Input Devices

Devices which let you enter data into the computer • keyboard • mouse / • • scanner • • Output Devices

• Sends data out from the computer to be seen in a human readable way: text, pictures, sound,… • Examples: – Monitor – – GPS – Speakers Key Components Inside the Computer • : Holds the CPU, Memory, system Bus,… • Bus: Shared communication channel for the components • CPU: Brain • RAM: Holds data and instructions for currently running processes • Input/Output Processors: Perform input/output related processing Motherboard

• Main circuit board that contains the central electronic components of the computer • Holds the CPU, memory, connectors for the hard drive, optical drive, video cards,… • Connects directly or indirectly to every part of the computer System Bus

Communication link that connects all the different parts of the computer together. CPU (Central Processing Unit)

• Also called a processor • The brains of the computer • Controls functions performed by other components • Can perform up to 10s of billions of tasks per second • Processor speed is measured in megahertz (MHz) or gigahertz (GHz) • Well known manufactures are Intel and AMD CPU on Motherboard

CPU •Von Neumann Architecture

Computers built on the von Neumann model divide the computer hardware into four subsystems: memory, , control unit, and input/output

Fig: The von Neumann model ● von Neumann Architecture: Four subsystems

● Memory − Memory is the storage area − Generally, RAM

● Arithmetic logic unit (ALU) − The ALU is where calculation and logical operations take place. − Like Addition, Subtraction

● Control unit − The control unit controls the operations of the memory, ALU, and the input/output subsystem.

● Input/output − The input subsystem accepts input data and the program from outside the computer. − The output subsystem sends the result of processing to the outside. The stored program concept The von Neumann model states that the program must be stored in memory. This is totally different from the architecture of early computers in which only the data was stored in memory: the programs for their task was implemented by manipulating a set of switches or by changing the wiring system.

The memory of modern computers hosts both a program and its corresponding data. This implies that both the data and programs should have the same format, because they are stored in memory. In fact, they are stored as binary patterns in memory—a sequence of 0s and 1s. Figure Program and data in memory How Does the CPU Process? The Fetch-Execute Cycle • The CPU performs the following commands in succession for every instruction – Fetch: Get next instruction – Decode: Determine what type of instruction – Get Data: If external data is needed, it retrieves it – Execute: Perform the operation – Store: Save result

System Clock

• Acts as a metronome. Each tick (Clock Cycle) it executes the next instruction • The clock speed is measured in Hertz (Hz) CPU Instruction Cycle

Clock Ticks Instruction 1 0 Fetch 1 Decode 2 Execute 3 Store Instruction 2 4 Fetch 5 Decode 6 Execute 7 Store Single vs. Dual-Core Processor

• Processors become more efficient when they have multiple core’s. • Multiple core’s allow the processor to execute multiple instructions at the same time. 32bit word vs. 64 bit

• The word size is describing the size of the instructions which can be executed

32 Bit 64 Bit

Fetch Cookies Fetch Cookies & Milk Fetch Milk Eat Cookies & Milk Eat Cookies Eat Milk Memory

• The computer associates locations (addresses) with contents. Just like your own brain, it has a certain spot where it stores certain information • . Address Contents 00000000 11011001 00000001 10010101 00000010 11111101 00000011 10000001 00000100 01011001 00000101 00111001 RAM (Random Access Memory)

• This memory holds the data the computer is currently using • It is called Random Access because you can retrieve any piece of data at any time, you do not need to sequentially retrieve it • Much faster to read and write from than the hard drive • Temporary or volatile storage, this data is erased when the computer is shut down. Must save to hard drive • Measured in megabytes (MB), or gigabytes (GB) RAM on Motherboard ROM (Read Only Memory)

• Memory which holds the startup instructions for the computer • The instructions are permanently stored in this memory • Non-volatile Data Storage

• RAM is useful for temporary storage (volatile) while the computer is running. Once the computer stops all data in RAM is gone • We need permanent storage locations such as hard drive, cloud, DVD, or a flash drive Hard Drive

• Nonvolatile storage (permanent) • Holds programs and data • Today’s hard drives have capacities up to 8TB • External hard drives can be connected to the computer via a port for additional/backup storage How Hard Drives Work

• Data is saved on the disk in a pattern of magnetized spots

Read write head can fail and lead to disk failures on your computer Hard Disk Organization

• When you save information to the hard drive it places the info around the tracks in sectors. Solid State Drive (SSD)

• A replacement for hard disk drives • They do not have moving parts, so they are less prone to failure • Run more efficiently, are less noisy, and emit less heat • Exist in your computer, in a drive bay. RAM

• The RAM holds the data and instructions your computer is currently using. Like the Cache this is volatile, and you need to store it away or it will be deleted when you close your computer • Think of this as a temporary shelf, that isn’t as accessible as the table, but is still easy to get to Hard Disk

• Here is your permanent storage. All data that you want to save needs to go here. • Think of this as your pantry, where you put all your items away at the end of cooking. Flash Drives

• External solid state drives • Can fit into your pocket Review

• Here’s a video of by How Stuff Works to review and visualize this pieces inside your computer

• http://computer.howstuffworks.com/23-comput er-tour-video.htm Inside your Computer Desktop or

Desktop Laptop • Less Portable • More portable • Less Expensive • More expensive • Harder to steal • Easier to steal • Easier to expand and • Harder to upgrade upgrade