Computer security

Computer security, cybersecurity or information technology security is the protection of computer systems and networks from the theft of or damage to their hardware, software, or electronic data, as well as from the disruption or misdirection of the services they provide.

Computer Security and its types

• Information Security is securing information from unauthorized access, modification & deletion

• Application Security is securing an application by building security features to prevent from Cyber Threats such as SQL injection, DoS attacks, data breaches and etc.

• Computer Security means securing a standalone machine by keeping it updated and patched

• Network Security is by securing both the software and hardware technologies

• Cyber Security is defined as protecting computer systems, which communicate over the computer networks

Why is Computer Security Important?

In this digital era, we all want to keep our computers and our personal information secure and hence computer security is important to keep our personal information protected. It is also important to maintain our computer security and its overall health by preventing viruses and malware which would impact on the system performance.

Computer Security Practices

Computer security threats are becoming relentlessly inventive these days. There is much need for one to arm oneself with information and resources to safeguard against these complex and growing computer security threats and stay safe online. Some preventive steps you can take include:

• Secure your computer physically by:
  • Installing reliable, reputable security and anti-virus software
  • Activating your firewall, because a firewall acts as a security guard between the internet and your local area network 
• Stay up-to-date on the latest software and news surrounding your devices and perform software updates as soon as they become available
• Avoid clicking on email attachments unless you know the source 
• Change passwords regularly, using a unique combination of numbers, letters and case types
• Use the internet with caution and ignore pop-ups, drive-by downloads while surfing
• Taking the time to research the basic aspects of computer security and educate yourself on evolving cyber-threats
• Perform daily full system scans and create a periodic system backup schedule to ensure your data is retrievable should something happen to your computer.

Computer security threats

Comupter Security Threats are possible dangers that can possibly hamper the normal functioning of your computer. In the present age, cyber threats are constantly increasing as the world is going digital. The most harmful types of computer security are:

Viruses

A computer virus is a malicious program which is loaded into the user’s computer without user’s knowledge. It replicates itself and infects the files and programs on the user’s PC. The ultimate goal of a virus is to ensure that the victim’s computer will never be able to operate properly or even at all. 

Computer Worm

A computer worm is a software program that can copy itself from one computer to another, without human interaction. The potential risk here is that it will use up your computer hard disk space because a worm can replicate in greate volume and with great speed.

Phishing

Disguising as a trustworthy person or business, phishers attempt to steal sensitive financial or personal information through fraudulent email or instant messages. Phishing in unfortunately very easy to execute. You are deluded into thinking it’s the legitimate mail and you may enter your personal information.

Botnet

A botnet is a group of computers connected to the internet, that have been compromised by a hacker using a computer virus. An individual computer is called ‘zombie computer’. The result of this threat is the victim’s computer, which is the bot will be used for malicious activities and for a larger scale attack like DDoS.

Rootkit

A rootkit is a computer program designed to provide continued privileged access to a computer while actively hiding its presence. Once a rootkit has been installed, the controller of the rootkit will be able to remotely execute files and change system configurations on the host machine.

Keylogger

Also known as a keystroke logger, keyloggers can track the real-time activity of a user on his computer. It keeps a record of all the keystrokes made by user keyboard. Keylogger is also a very powerful threat to steal people’s login credential such as username and password.

 

Fundamental Concepts

A computer is basically a programmable machine capable to perform arithmetic and logical operations automatically and sequentially. It is also known as a data processor, as it can store, process, and retrieve data as per the wish of the user.

Basic Functions of a Computer

Taking data and instructions from a user, processing the data as per instructions, and displaying or storing the processed data, are the four major functions of a computer. These functions are also known as the input function, process function, output function, and storage function, respectively.

To provide these functions, a computer uses its components or devices. Usually, components of a computer are designed to perform only one of these four functions. But, some specialized components or devices are designed to perform two, three or all four functions. For example, a hard disk can perform three functions: input (when files are read), storage (when files are saved), and output (when files are written).

Components or devices of a computer, based on the function in which they are used, can be classified into four major types: the input devices, output devices, storage devices, and processing devices. For example, if a component processes the given instructions, the component is known as the processing device. Or if a device displays the processed data, the device is known as the output device.

Input function and devices

 

A computer is a data processing machine. It does nothing until a user (or a script or a program) provides the data that needs to be processed and the instructions that tell it how to process the data.

Any standard device or component that a user uses to instruct a computer is known as the standard input device. In other words, a computer uses its standard input devices or components to get instructions from a user.

The most common input devices are the keyboard and mouse. Almost all modern computers have these devices. Other common input devices are scanners, microphones, USB drives, and webcams.

Input data and instruction can also be generated from a non-standard input device such as the hard disk and CD/DVD. For example, a batch file in the Windows system may instruct the CPU to execute a program or a script at a particular time.

Installation disks are another good example of non-standard input devices. Usually, they contain a script or an executable program that automatically starts the installation process as soon as the disk is read.

Process function and devices

Once the data and instructions are received by the input function, the computer starts the processing function. In this function, a computer processes the received data according to the instructions.

To process the input data according to the instructions, the computer uses the CPU. A CPU is the main processing component of a computer. It processes user instructions, executes scripts and programs, and runs commands of the OS that provide a platform for installing and using application software.

Other important processing components are auxiliary processors. Auxiliary processors are also known as onboard processors. Auxiliary processors are used in devices to enhance their functionalities. You can think of an auxiliary processor as the private CPU of a device.

Only components or devices that provide the complex functionality such as Graphics cards, I/O devices, and network interface cards use auxiliary processors. For example, if a user draws an image, the auxiliary processor on the graphics card performs all calculations that require in drawing the image on the display device.

The following image shows a sample of both a CPU and an auxiliary processor.

Output function and devices

 

After processing the input data, the CPU, auxiliary processor, or the process function sends the processed data to the output function or to the default or configured output device. By default, computers use monitors as the default output device.

Aside from monitor, a variety of output devices are also available. Each output device presents the processed data in a different form, for example, a monitor, a printer, and a speaker displays, prints, and plays the processed data, respectively.

A user, based on his requirement, can connect and use two, three or more output devices to the computer. For example, after viewing the processed data, a user can send it to the printer for printing.

Storage function and devices

Storing data and information is the fourth major function of a computer. This function allows us to save the processed data for later use. To store data and information, a computer uses two types of storage components: temporary and permanent.

Temporary storage components are used to store data temporarily. Data stored in a temporary storage component is erased when the system is shutdown. RAM is a compulsory temporary storage component. A computer uses the ram to store the running applications and their data.

Permanent storage components are used to store data permanently. Data stored in a permanent storage component is not erased when the system is shutdown. The hard disk is the most common permanent storage component. Usually, all computers have at least one hard disk to store data. Other common permanent storage components or devices are external drives, USB drives, and CD/DVD.

The 4 Primary Hardware Concerns for New Computers

Computer descriptions these days come with a lot of specifications that use a lot of technical jargon. This can be confusing if you aren't sure what you're looking for! By following the information listed below, you can look for key words that will help you zero in on the computer that will last for your entire time here at UNI!

Computer Speed (the processor)

The most common processor found in computers today is from Intel. The Intel Core series of processors perform well and are generally recommended for a computer that you will bring to UNI. When reading a computer listing, look for something similar to Intel 6th generation Core processors. For gaming, intense graphic design or video editing, or just maximum longevity, pick a Core i7 processor (the most powerful). The Core i7 processor will deliver the fastest speed and most processing power. Keep in mind, on laptops, a Core i7 may slightly reduce the battery life due to the extra power needs for the stronger processor. UNI Information technology recommends a Core i5 at a minimum.

Storage (the hard drive)

Hard drives come in two varieties today: the magnetic, spinning disk (HDD) or the Solid State Drive (SSD). SSDs are more expensive, but recommended for maximum longevity of your computer.

• The spinning disk (HDD) is generally cheaper and comes in much larger sizes. These drives are good for storage (for example, if you have a lot of digital pictures, music, or movies). You can find HDDs in 500GB to several terabytes in size.
• The Solid State Drive (SSD) is generally smaller in terms of amount of storage available and more expensive. It is however, much faster than it's older, HDD cousin. Upgrading from an HDD to a SSD in an older computer will make it have new life! Ensuring the computer you bring to UNI has an SSD will make it faster and lighter. With cloud storage available to you at UNI (Google Drive), the smaller hard drive might not be an issue. Pick up an SSD no smaller than 256GB if possible.

Memory (RAM)

If a hard drive is like the bookshelf in a computer (where the computer stores information for retrieval, like a bookshelf storing books) then the RAM or computer's memory is like the desk surface. The larger the desk surface (the greater the amount of RAM or memory), the more things a person can do at once. If you have a large desk you can have several papers laying out at once, a book open, and generally it is more conducive to having more research materials spread out and available. Likewise, the more memory your computer has, the more programs or applications it can run at the same time. UNI recommends no less than 8GB of RAM. For maximum longevity, pick 16GB.

WiFi Ability (wireless network card)

UNI has deployed high-speed and secure WiFi across campus in areas that are important to students like Maucker Union, the Rod Library, classrooms, and even outside in some instances! To take full advantage of the WiFi, you should ensure that your wireless network card is a dual band radio capable of both 2.4GHz and 5GHz frequencies (most modern computers have this). You'll want to look for dual band AC wireless or something similar in the specifications listing. This will be the most compatible with UNI's wireless network.

Other Concerns for a New Computer

If you've followed the hardware advice above, you should have a computer that is fairly well equipped for your entire collegiate career here at UNI. There are a few other things to consider, however, when making a new computer purchase. The following section will review those with you.

Warranty

UNI Information Technology recommends a minimum three year hardware warranty. This will ensure the manufacturer or reseller will cover any broken computer hardware for at least three years. This is especially important for laptops as they are harder to work on yourself. 

UNI does not recommend that you purchase any type of software tuning/maintenance/assistance from your manufacturer or reseller. Some companies will try and sell you a "tune up" before you even walk out of the door! You do not need this assistance as Information Technology at UNI can help you with the software on your computer.

Size/Weight

More and more professors are allowing the use of laptops during class. A smaller, lighter laptop will be easier to carry across campus during your day. It is also more likely to have better battery life. Larger, heavier laptops are often-times better for gaming or video-intense applications, but will not be as fun to carry across campus.

Operating System

For Windows-based computers, UNI Information Technology recommends Windows 10 home or professional.

For Apple computers, UNI recommends the latest version of macOS.

Major/Field of Study

Some majors or fields of study use different types of computer hardware. It might be worth checking with the departmental office of the department your major resides in.

Motherboard

The motherboard is the backbone that ties the computer's components together at one spot and allows them to talk to each other. Without it, none of the computer pieces, such as the CPU, GPU, or hard drive, could interact. Total motherboard functionality is necessary for a computer to work well.

A motherboard provides connectivity between the hardware components of a computer, like the processor (CPU), memory (RAM), hard drive, and video card. There are multiple types of motherboards, designed to fit different types and sizes of computers.

Each type of motherboard is designed to work with specific types of processors and memory, so they don't work with every processor and type of memory. However, hard drives are mostly universal and work with the majority of motherboards, regardless of the type or brand.

Below is a picture of the ASUS P5AD2-E motherboard with labels next to each of its major components. Clicking on the image directs you to a larger and more detailed version.

What was the first motherboard?

The first motherboard is considered to be one used in the IBM Personal Computer, released in 1981. At the time, IBM called it a "planar" instead of a motherboard. The IBM Personal Computer and the motherboard inside it would set the standard for IBM-compatible computer hardware going forward.

Motherboard components

• Expension Slots
• 3 pin case fan connectors.
• Back pane connectors.
• Heat Sink.
• Inductor.
• Capacitor.
• CPU socket.
• Northbridge.
• Screw Hole.
• Memory Slot.
• Super I/O.
• Floopy Connection etc.

The Characteristics of a Motherboard

While many people think of the CPU as their computer's brain, the motherboard is like its nervous system and spinal cord. Not only does the motherboard provide a place for the CPU to sit, but it also handles every bit of data that passes in and out of the CPU.

Form Factor

While you can get capable motherboards in any size, its form factor is an important factor in choosing a motherboard. If you want to build a very small computer, a small form-factor board like a 9.6-inch square micro-ATX or 6.7-inch square mini-ITX board is your best choice. Larger motherboards, like the 11.2-by-8.2 inch mini-ATX or 12-by-9.6 inch full-size ATX board, not only fit in larger cases, but also have room for more components, connectors and expansion slots.

CPU Socket and Chipset

When choosing a motherboard, look for one with a CPU socket that will accommodate your chosen type of CPU. Not only do processors from Intel and AMD have different socket requirements, but different processors from the same manufacturers will also require a specialized socket. In other words, an Intel motherboard won't support an AMD processor and won't support certain Intel processors as well. In addition to choosing a compatible socket, the chipset on the motherboard will determine how quickly the computer can run, what additional features it supports and how much memory it can access.

Slots

Motherboards typically have three types of slots. Memory slots let you plug RAM modules into the computer. The more slots you have, the more memory you can add. The slots are also specific to a given type of RAM, so a motherboard with double data rate type 3 slots will only accept DDR3 memory modules. Motherboards also have high-speed PCI Express slots for graphics cards as well as regular PCI slots for expansion cards. While devices that once would have plugged into a PCI slot, like video capture cards or modems, are frequently now available as USB devices, the high-speed PCI-Express x16 slots are still necessities for graphics cards.

Connectors

Motherboards have a broad range of both internal and external connectors. At a minimum, you can expect to find internal USB headers and external USB ports, internal serial advanced technology attachment ports for drives, connectors for case LEDs and switches, and external audio ports. Some motherboards add support for USB 3.0, graphics connectors for their on-board graphics system, an external eSATA port for high-speed connections to external drives and even legacy ports like parallel or serial connectors.

 

ROM

ROM (read only memory) is a flash memory chip that contains a small amount of non-volatile memory. Non-volatile means that its contents cannot be changed and it retains its memory after the computer is turned off.

History of ROM

Read-only memory were employed as non-volatile storage for programs in most early stored-program computers, such as ENIAC after 1948. ... Most home computers of the 1980s stored a BASIC interpreter or operating system in ROM as other forms of non-volatile storage such as magnetic disk drives were too costly.

Types of ROM

• Programmable read-only memory (PROM), or one-time programmable ROM (OTP), can be written to or programmed via a special device called a PROM programmer. Typically, this device uses high voltages to permanently destroy or create internal links (fuses or antifuses) within the chip. Consequently, a PROM can only be programmed once.

• Erasable programmable read-only memory (EPROM) can be erased by exposure to strong ultravoilet light (typically for 10 minutes or longer), then rewritten with a process that again requires application of higher than usual voltage. Repeated exposure to UV light will eventually wear out an EPROM, but the endurance of most EPROM chips exceeds 1000 cycles of erasing and reprogramming. EPROM chip packages can often be identified by the prominent quartz "window" which allows UV light to enter. After programming, the window is typically covered with a label to prevent accidental erasure. Some EPROM chips are factory-erased before they are packaged, and include no window; these are effectively PROM.

• Electrically erasable programmable read-only memory (EEPROM) is based on a similar semiconductor structure to EPROM, but allows its entire contents (or selected banks) to be electrically erased, then rewritten electrically, so that they need not be removed from the computer (or camera, MP3 player, etc.). Writing or flashing an EEPROM is much slower (milliseconds per bit) than reading from a ROM or writing to a RAM (nanoseconds in both cases).

Where is the ROM on a computer?

For the computer, the main EEPROM and BIOS is on the computer motherboard.

How does ROM work?

ROM is sustained by a small, long-life battery in the computer. It contains two basic components: the decoder and the or logic gates. In ROM, the decoder receives input in binary form; the output will be the decimal equivalent. The OR gates in ROM use the decoder's decimal output as their input.

ROM performs like a disk array. It contains a grid of rows and columns that are used to turn the system on and off. Every element of the array correlates with a specific memory element on the ROM chip. A diode is used to connect the corresponding elements.

When a request is received, the address input is used to find the specific memory location. The value that is read from the ROM chip should match the contents of the chosen array element.

 

 

 

RAM

Alternatively referred to as main memory, primary memory, or system memory, RAM (random-access memory) is a hardware device that allows information to be stored and retrieved on a computer. RAM is usually associated with DRAM, which is a type of memory module. Because data is accessed randomly instead of sequentially like it is on a CD or hard drive, access times are much faster. However, unlike ROM, RAM is a volatile memory and requires power to keep the data accessible. If the computer is turned off, all data contained in RAM is lost.

History of RAM

The first form of RAM came about in 1947 with the use of the Williams tube. It utilized a CRT (cathode ray tube); the data was stored on the face as electrically charged spots.

The second widely used form of RAM was magnetic-core memory, invented in 1947. Frederick Viehe is credited with much of the work, having filed for several patents relating to the design. Magnetic-core memory works through the use of tiny metal rings and wires connecting to each ring. One bit of data could be stored per ring and accessed at any time.

However, RAM, as we know it today, as solid state memory, was first invented in 1968 by Robert Dennard. Known specifically as dynamic random-access memory, or DRAM, transistors were used to store bits of data.

 

Types of RAM

• DRAM (pronounced DEE-RAM), is widely used as a computer’s main memory. Each DRAM memory cell is made up of a transistor and a capacitor within an integrated circuit, and a data bit is stored in the capacitor. Since transistors always leak a small amount, the capacitors will slowly discharge, causing information stored in it to drain; hence, DRAM has to be refreshed (given a new electronic charge) every few milliseconds to retain data.
• SRAM (pronounced ES-RAM) is made up of four to six transistors. It keeps data in the memory as long as power is supplied to the system unlike DRAM, which has to be refreshed periodically. As such, SRAM is faster but also more expensive, making DRAM the more prevalent memory in computer systems.

What are the common types of DRAM?

• Synchronous DRAM (SDRAM) “synchronizes” the memory speed with CPU clock speed so that the memory controller knows the exact clock cycle when the requested data will be ready. This allows the CPU to perform more instructions at a given time. Typical SDRAM transfers data at speeds up to 133 MHz.
•  Rambus DRAM (RDRAM) takes its name after the company that made it, Rambus. It was popular in the early 2000s and was mainly used for video game devices and graphics cards, with transfer speeds up to 1 GHz.
• Double Data Rate SDRAM (DDR SDRAM) is a type of synchronous memory that nearly doubles the bandwidth of a single data rate (SDR) SDRAM running at the same clock frequency by employing a method  called "double pumping," which allows transfer of data on both the rising and falling edges of the clock signal without any increase in clock frequency.

Computer Memory

In computing, memory refers to a device that is used to store information for immediate use in a computer or related computer hardware device. It typically refers to semiconductor memory, specifically metal–oxide–semiconductor memory, where data is stored within MOS memory cells on a silicon integrated circuit chip.

Types of Computer Memory: Primary and Secondary

Although many types of memory in a computer exist, the most basic distinction is between primary memory, often called system memory, and secondary memory, which is more commonly called storage.

The key difference between primary and secondary memory is speed of access.

• Primary memory includes ROM and RAM, and is located close to the CPU on the computer motherboard, enabling the CPU to read data from primary memory very quickly indeed. It is used to store data that the CPU needs imminently so that it does not have to wait for it to be delivered.
• Secondary memory by contrast, is usually physically located within a separate storage device, such as a hard disk drive or solid state drive (SSD), which is connected to the computer system either directly or over a network. The cost per gigabyte of secondary memory is much lower, but the read and write speeds are significantly slower.

Primary Memory Types: RAM and ROM 

There are two key types of primary memory:

• RAM, or random access memory
• ROM, or read-only memory

Let's look in-depth at both types of memory.

RAM Computer Memory

The acronym RAM stems from the fact that data stored in random access memory can be accessed – as the name suggests – in any random order. Or, put another way, any random bit of data can be accessed just as quickly as any other bit.

The most important things to understand about RAM are that RAM memory is very fast, it can be written to as well as read, it is volatile (so all data stored in RAM memory is lost when it loses power) and, finally, it is very expensive compared to all types of secondary memory in terms of cost per gigabyte. It is because of the relative high cost of RAM compared to secondary memory types that most computer systems use both primary and secondary memory.

Data that is required for imminent processing is moved to RAM where it can be accessed and modified very quickly, so that the CPU is not kept waiting. When the data is no longer required it is shunted out to slower but cheaper secondary memory, and the RAM space that has been freed up is filled with the next chunk of data that is about to be used.

Types of RAM

• DRAM: DRAM stands for Dynamic RAM, and it is the most common type of RAM used in computers. The oldest type is known as single data rate (SDR) DRAM, but newer computers use faster dual data rate (DDR) DRAM. DDR comes in several versions including DDR2 , DDR3, and DDR4, which offer better performance and are more energy efficient than DDR. However different versions are incompatible, so it is not possible to mix DDR2 with DDR3 DRAM in a computer system. DRAM consists of a transistor and a capacitor in each cell.
• SRAM: SRAM stands for Static RAM, and it is a particular type of RAM which is faster than DRAM, but more expensive and bulker, having six transistors in each cell. For those reasons SRAM is generally only used as a data cache within a CPU itself or as RAM in very high-end server systems. A small SRAM cache of the most imminently-needed data can result in significant speed improvements in a system

The difference between DRAM and SRAM is that SRAM is faster than DRAM - perhaps two to three times faster - but more expensive and bulkier. SRAM is usually available in megabytes, while DRAM is purchased in gigabytes.

DRAM uses more energy than SRAM because it constantly needs to be refreshed to maintain data integrity, while SRAM  - though volatile – does not need constant refreshing when it is powered up.

ROM Computer Memory

ROM stands for read-only memory, and the name stems from the fact that while data can be read from this type of computer memory, data cannot normally be written to it. It is a very fast type of computer memory which is usually installed close to the CPU on the motherboard.

ROM is a type of non-volatile memory, which means that the data stored in ROM persists in the memory even when it receives no power – for example when the computer is turned off. In that sense it is similar to secondary memory, which is used for long term storage.

When a computer is turned on, the CPU can begin reading information stored in ROM without the need for drivers or other complex software to help it communicate. The ROM usually contains "bootstrap code" which is the basic set of instructions a computer needs to carry out to become aware of the operating system stored in secondary memory, and to load parts of the operating system into primary memory so that it can start up and become ready to use.

ROM is also used in simpler electronic devices to store firmware which runs as soon as the device is switched on.

Types of ROM

ROM is available in several different types, including PROM, EPROM, and EEPROM.

• PROM PROM stands for Programmable Read-Only Memory, and it is different from true ROM in that while a ROM is programmed (i.e. has data written to it) during the manufacturing process, a PROM is manufactured in an empty state and then programmed later using a PROM programmer or burner.
• EPROM EPROM stands for Erasable Programmable Read-Only Memory, and as the name suggests, data stored in an EPROM can be erased and the EPROM reprogrammed. Erasing an EPROM involves removing it from the computer and exposing it to ultraviolet light before re-burning it.
• EEPROM EEPROM stands for Electrically Erasable Programmable Read-Only Memory, and the distinction between EPROM and EEPROM is that the latter can be erased and written to by the computer system it is installed in. In that sense EEPROM is not strictly read-only. However in many cases the write process is slow, so it is normally only done to update program code such as firmware or BIOS code on an occasional basis

Secondary Memory Types

• Hard Disk Drives

• Solid State Drives
• Optical Drives
• Tape Drives

 

 

Output Devices

There are several output devices that are as follows:

Monitor

This is the most common computer output device. It creates a visual display by the use of which users can view processed data.  Monitors come in various sizes and resolutions.

Common Types of Monitors

• Cathode Ray Tube – this uses phosphorescent dots to generate the pixels that constitute displayed images.
• Flat Panel Screen – this makes use of liquid crystals or plasma to produce output. Light is passed through the liquid crystals in order to generate pixels.

Printer

This device generates a hard copy version of processed data, like documents and photographs. The computer transmits the image data to the printer, which then physically recreates the image, typically on paper.

Types of Printers

• Ink Jet – this kind of printer sprays tiny dots of ink onto a surface to form an image.
• Laser – this type utilises toner drums that roll through magnetized pigment, and then transfers the pigment onto a surface.
• Dot Matrix – dot matrix printers utilise a print head to set images on a surface, using an ink ribbon.

Speakers

speakers are attached to computers to facilitate the output of sound; sound cards are required in the computer for speakers to function. The different kinds of speakers range from simple, two-speaker output devices right the way up to surround-sound multi-channel units.

Headset

This is a combination of speakers and microphone.  It is mostly used by gamers, and is also a great tool for communicating with family and friends over the internet using some VOIP program or other.

Projector

 This is a display device that projects a computer-created image onto another surface: usually some sort of whiteboard or wall. The computer transmits the image data to its video card, which then sends the video image to the projector. It is most often used for presentations, or for viewing videos.