Module 8.1 "Units Of Speed And Capacity" Study Guide

Module 8.1 "Units Of Speed And Capacity” Objectives

• 1.3 Compare and contrast common units of measure.

• 2.3 Compare and contrast storage types.

Storage Units (8.1.1)

• Storage in a computer is called "persistent" because it holds data even when the power is turned off.

• This data can include the operating system like Windows or iOS, as well as all the apps and user files added to the system.

• Each piece of data has a file size, which is the number of bytes it takes up.

• Computer storage for files has grown to be measured in gigabytes (GB) or terabytes (TB).

• These units can also be used for memory and storage drives.

• A gigabyte (GB) is about one billion bytes.

• A terabyte (TB) is one thousand times bigger than a gigabyte!

• Memory is "non-persistent" or "volatile" storage, which means it only holds data while the computer is powered on.

• A solid-state drive (SSD), on the other hand, keeps the data permanently.

• The smallest addressable unit in memory is a byte. When we gather 1024 bytes, we call it a kilobyte (KB).

• As we keep multiplying up to 1024 kilobytes, we get to the next storage unit: megabytes (MB). After megabytes come gigabytes (GB), then terabytes (TB), followed by petabytes (PB), exabytes (EB), zettabytes (ZB), and yottabytes (YB).

• Most files today are measured in megabytes (MB)—music and photos are good examples. Larger files, such as videos, are usually measured in gigabytes (GB). Only small text files are measured in kilobytes (KB) these days.

Adding commas to numbers greater than 999 is not common in IT communications. This is because different regions separate the thousands digit in different ways.

Additionally, the comma in programming is used to separate items when coding. To avoid confusion around the world, it was simply decided to leave off any punctuation.

Throughput Units (8.1.2)

• Throughput measures how much of something passes through something else in a certain amount of time.

• Amount of data transfer supported by a link in typical conditions. This can be measured in various ways with different software applications. Goodput is typically used to refer to the actual "useful" data rate at the application layer (less overhead from headers and lost packets).

• It measures how fast things move or get done.

• With computers, this means how much data moves through the system in one second.

• With networking, it's similar but slightly different. it’s about how much data moves from one place to another in one second.

• You can also think of it as the amount of data passing through the network at any given moment.

• t's important to know that throughput is not the highest or lowest amount. Throughput is the total amount over a certain block of time.

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Moving Bits

• When we talk about how fast data moves, we use bits, which are much smaller than bytes. In fact, one byte is equal to eight bits.

• Network transfers break it down to the smallest units possible, bits per second. But when you check your Internet speed, the results are shown as Mbps, which means megabits per second.

• If you want to send a video to a friend over the Internet, the speed is measured in megabits (Mb) or gigabits (Gb) per second.

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Bandwidth

• Bandwidth is the highest amount of data that a network can handle at once.

• For example, if a network has a bandwidth of 50 megabits per second (Mbps), it can't send data faster than that number.

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Throughput Units

• Kilobits per second (Kbps): One thousand (1,000) bits per second. Slow network links are measured in Kbps.

• Megabits per second (Mbps): One million (1,000,000) bits per second. Wireless networks and residential Internet links typically have this rate of throughput.

• Gigabits per second (Gbps): One billion (1,000,000,000) bits per second. The latest PC bus standards and networks can support this higher level of throughput.

• Terabits per second (Tbps): One trillion (1,000,000,000,000) bits per second. This sort of capacity is found in major telecommunications links between data centers, cities, and countries.

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Throughput Obstacles

• There are multiple factors that can affect a network's throughput.

• Some things that can slow it down are:

  • latency

  • errors that cause data to be sent again (retransmissions),

  • the communication rules (protocols).

    • Some protocols have built-in features like congestion avoidance and flow control, which can impact throughput.

• If a data packet gets lost, it might need to be resent. If this happens a lot, it can cause more congestion and slow down the network.

• Your Internet Service Provider (ISP) gives you a certain amount of bandwidth, However, the actual speeds you get might be different from what is advertised.

• Inside your home network, speeds between devices can be faster because they don't depend on the Internet bandwidth.

• It's common for ISPs to under promise and over deliver.

• Another obstacle can be the amount of traffic passing through the network. If there's a lot of traffic on the network at once, congestion occurs, making everything slower.

• The cables you use also affect your network speed. The network can only be as fast as its slowest part. This is called the weak link.

Processing Speed (8.1.3)

• Processing speed describes how fast the computer itself works during a given operation or task.

• A computer's speed is measured by its internal clock and its processors, also known as the central processing unit (CPU).

• This speed is measured in Hertz (Hz), where 1 Hz means one cycle per second.

• A cycle would just be how many times a process reoccurs.

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Clock Speed

• On a computer, laptop, tablet, or phone, the internal parts move data around using a synchronized clock.

• All these devices use a master clock to stay synchronized, or to stay working together smoothly.

• The signal from the master clock is called a square wave. These square waves work for computers because they represent binary digits: the 1s and 0s. The wave goes up and over, then down and over in one cycle. If you see four cycles happening in one second, the clock signal is running at 4 Hertz (4 Hz).

• At first, processors were measured in Megahertz (MHz), which means 1 million cycles per second. But as technology improved, we started measuring them in Gigahertz (GHz), which means 1 billion cycles per second.

• Today's processors usually run at between 2 to 4 GHz.

• the fastest CPUs can reach up to 6 GHz.

• It's hard to get CPU speeds faster than they are now, as this amount of activity creates a lot of heat. Heat is an enemy of computers, especially laptops.

• Even though servers are powerful types of computers, they don't have specialized processors. Servers use the same kind of processors as the ones in your home computer.