Computer Systems

Advantages of magnetic storage

- Very large storage capacity. - It is a lot faster than optical disks at storing and receiving data. - Unlike RAM, it is non-volatile so data is not lost when the computer is switched off. - It is cheaper per MB than other storage medias.

Role of maintenance utilities - system information and diagnosis

An information system (IS) is any organized system for the collection, organization, storage and communication of information. More specifically, it is the study of complementary networks that people and organizations use to collect, filter, process, create and distribute data.

Role of security - antivirus

Anti-virus software is designed to detect and block viruses and attacks from malware

What is cloud storage

Cloud storage uses magnetic and, increasingly, solid-state storage at a remote location. In cloud storage, data is stored and is accessible from multiple distributed and connected resources that compromise a cloud via the internet.

Role of maintenance utilities - system cleanup tools

Disk Cleanup (cleanmgr.exe) is a computer maintenance utility included in Microsoft Windows designed to free up disk space on a computer's hard drive.

Role of disk organisation utilities - file transfer and management

Files are stored on the hard disk in blocks wherever there is space. If you have a big file it might get split up into segments so if it can be stored in the available gaps. This isn't very efficient because the operating system then has to keep track of where all the segments are. After a while, thousands of files are stored in segments all over the disk. The files have been 'fragmented'

What is clock

Used to synchronise all things inside the computer. The start of each clock cycle is when the clock signal goes from '0' to '1', the clock signal is measured in a unit called Hertz (Hz), which is the number of clock cycles per second.

Effect of number of cores on CPU performance

- A CPU can contain one or more processing units known as cores. Each core contains and ALU, control unit and registers. CPUs ith multiple cores have more power and can therefore run a number of programs at the same time. - If you have the double the amount of cores, it won't be double the speed because each CPU has to communicate with the other and this uses up some of the extra speed.

Advantages of solid state disks

- Low power consumption - Durable than hard disk drives - No noise while in operation - Compact than hard disk drives - Faster than hard disk drives

What are operating systems

- A complex piece of software found on most computer systems. It controls the general operation of a computer, and provides an easy way for us to interact with computers and run applications. - [Group of programs] that manages the computer's resources and allows application software to communicate with the hardware. It includes the management of: - Processor(s) - Memory - Input/output devices (periphery management) - Applications - Security - Examples of operating systems include Macintosh OS X, Windows, Blackberry (RIM OS), iOS

Role of security - firewall

- A firewall is software that will block unexpected connections coming into the network - It can also be used to filter between trusted and untrusted networks and prevent programs from communicating through the use of ports.

What is the CPU (central processing unit)

- A type of processor that runs the system. The name, processor, is a more generic term but is often used to mean the same thing. (The only problem with using the term processor, when referring to the CPU, is that there will be other processors in a computing system but only one CPU) - The major components of a CPU includes: - arithmetic logic unit - control unit - clock - bus

Explain how an embedded system differs from a non-embedded system

- An embedded operating system does not load and execute other applications so the system is only able to run a single application. - In embedded systems, the software typically resides in firmware, such as flash memory or ROM chip. In general purpose computers loads programs into RAM each time. The coding on an embedded system is, therefore, totally focused on controlling and managing the system (or hardware). The code is written to fully use the the potential of the connected hadware and manage it for the benefit of the user. Though there is still data and algorithms in embedded systems, they only control and manage the specific connected hardware.

What are the majority of secondary storage devices used for

- Back up data - Add more storage space for files/ pictures/ videos etc. - Easily transport files - Share files over a network

Effect of caches on CPU performance

- Cache is a small amount of memory which is a part of the CPU - closer to the CPU than RAM. It is used to temporarily hold instructions and data that the CPU is likely to reuse. - The more cache memory a computer has, the more data and instructions can be held in cache and made available very quickly because it is always located on the same microchip as the CPU which means it can be accessed much more quickly than ordinary RAM - There are different levels of cache; - level 1 cache: part of the CPU chip, is the smallest and fastest to access - level 2 cache: still on the same chip but the stage further from the processor - level 3 cache: works to improve the performance of L1 and L2 and is slower

What is bus

- Carries data and operations as a standard bus, however it is only used for connecting and interacting with internal computer components. CPU Bus is internal to the CPU and is used to transpor data to and from the ALU. - A bus is a collection of wires through which data is transmitted from one component to another. Main memory will be considered to be any form of memory that is directly accessible by the CPU, except for cache and registers. - Adress bus sends data in one direction (from the CPU to the RAM) - Data bus sends data to the memory or receives data from teh memory so data can flow both ways.

Role of data compression utilities (compression software)

- Compression software will reduce the size of files so they take up less disk space. It's used loads on the internet to make files quicker to download. Standard file formats include .zip and .rar. - Compressed files need to be extracted before they can be used.

Disadvantages of optical storage

- Data on write-once disks (CD-R, DVD-R) are permanent and cannot be changed - Optical storage does not provide enough data storage in comparison to other storage technologies - Optical storage is expensive per GB in comparison to other methods - It requires special drives to read/write: limited number of writes - Formats like CD-R and DVD-R, BD-R have no standards for longevity tests, which means the user does not know how long it's life span is - It can be easily broken, scratched or damaged by heat and light

Role of disk organisation utilities - disk defragmenter

- Defragmentation software reorganises data on the hard drive to put fragmented files back together and it also moves files to collect all the free space together. This helps prevent further fragmentation and will improve file access times. - Most modern OS run this process automatically. It is used to speed up your hard disk

What is an embedded system

- Embedded systems are computers built into other devices, like diswashers, microwaves and TVs. They are usually dedicated systems: e.g a computer used to control a car is embedded, the microprocessor controlling a washing machine is embedded - Are used as control systems: they monitor and control machinery in order to achieve a desired result e.g in a dishwasher the embedded system could control the water pumps and water release mechanisms, manage the various dishwasher cycles and control the thermostat to keep the water at an appropriate temperature - As they are dedicated to a single task, embedded systems are usually easier to design, cheaper to produce, and more efficient at doing their task than a general purpose computer

Role of security - encryption software

- Encryption tools can help to keep sensitive data safe from cyber-criminals or unauthorised access - Files that are encrypted have been altered using a secret code and are unreadable to unauthorised parties

Disadvantages of magnetic storage

- Hard drives have moving parts which can fail. - - Crashes can damage to surface of the disk, leading to loss of data. - Easily damaged if dropped. Use a large amount of power compared to other media. - Can be noisy. - Mechanical parts that can fail.

Advantages of optical storage

- It is easy to store and transport - Can read in a number of devices - If looked after it can be longlasting, - Non-volatile - Random access - Cheap to produce.

Role of application management

- It is the operating system that provides information about all user programs running on your computer and provides a user interface so it is easy to interact with the computer - The operating system does the following application management activities: - loads a program into memory - allows the application software to communicate with the hardware - provides a mechanism for processing all internal communication

What is memory (main memory)

- Memory is the area where the computer stores or remember data. Memory provides the CPU with its instructions. There are different types of memory, and each one plays an important role in the running of a computer system. RAM is used as the main memory in a computer. It can be read and written to. - Memory is either volatile( temprorary) or non-volatile (permanent) - Main memory is any form of memory that is diectly accessible by the CPU, except for cache and registers

Disadvantages of solid state disks

- More expensive than hard disk drives - Limited storage capacity - Poor availability - Shorter lifespan than hard disk drives

Disadvantages of Von Neumann architechture

- Only 1 bus (pathway) connecting the memory and the processor therefore only 1 part of an instruction or data item can be fetched at a time so the processor may have to wait longer for the data/ instruction to arrive

What are the 3 types of storage mediums

- Optical - Magnetic - Solid state

What is meant by application software

- Programs that enable a user to perform a task e.g if the user needs to do such as write an essay, keep a set of class marks, record pupil attendance or process orders - Includes software such as microsoft office, microsoft excel, microsoft outlook, macOS

What are utility programs

- Programs that provide additional capabilities to manage the computer beyond those provided by the operating system. Utility software is used to help to manage, maintain and control computer resources. - The utilities include: - Security utilities that keep your data safe e.g encryption software - Disk organisation utilities that organise your files into folders and tidy up the disk - Data compression utilities - File backup utilities

Role of security

- Provides security through user accounts and passwords - The OS security includes many ways to ensure safety from threats and attacks. These securities functions include encrypting files that are stored on the hard disks, controlling the access to a computer by setting the passwords for different users

What is RAM

- RAM is the main place for storing instructions and data whilst a program is being executed. Program is copied into RAM before the CPU can run the program - It is usually measured in gigabytes. The more gigabytes of RAM a computer has, the more programs and operations it can handle at the same time. - When RAM is full, the computer may need to move the application data somewhere else. It moves data that hasn't been recently uses to a location on secondary storage (non-volatile: e.g CDs and SD cards) known as virtual memory. RAM is volatile

What is ROM

- ROM is a flash memory chip that contains a small amount of non-volatile memory. It is built onto the motherboard. It is used in SD cards, USB sticks and solid state drives (SSDs). - It contains the BIOS (Basic Input Output System) which are instructions a computer needs to properly boot up (the firmware for the motherboard) - BIOS contains the program which takes the computer through steps that lead up to the loading of the operating system. It happens between turning the power on and the computer indicating (beeping) to say it is starting to load the OS. - The CPU will read instructions from the ROM telling it to perform self-checks and set up the computer.

Explain Von Neumann architchture

- Relates to the relationship between the hardware that makes up a computer system - Uses one memory for both instructions and data - Cannot distinguish between data and instructions in a memory location - Executes programs by doing one instruction after the next in a serial manner using a fetch - decode - execute cycle - Is much better and used a lot since the model only needs 1 RAM as it stores data and instructions together. This is much cheaper than having 2 separate RAMs: 1 for data and instructions

Advantages of Von Neumann architechture

- Simplifies the micro-controller chip design because only one memory is accepted - Allows greater flexibility in developing software, particularly in the development of operating systems

Example of non-embedded system

- Smartphone (?)

What is the control unit

- The CU handles all processor control signals. It directs all input and output flow, fetches code for instructions from microprograms and directs other units and models by providing control and timing signals - Functions are: - it controls the execution of instructions in the correct sequence - it decodes instructions - it regulates and controls processor timing using regular pulses from the system clock - it sends and receives control signals to and from other devices within the computer

What is meant by system software

- These are programs that are needed to enable the computer to function. (Designed to run and maintain a computer sytem) - It includes the operating system, utilities, library routines and programming language translators. The most important one is the operating system (OS). There's also utility software (US) but that's referenced as the runner up.

What are embedded systems

- They are dedicated systems that are designed for a fixed purpose. - Examples of items that use this technology includes vehicles, cameras, medical equipment, firdges, TV, lifts, traffic lights, microwave ovens - Advantages include: - makes devices easier to use - increases reliability - offers features which enhance their usability

Advantages of cloud storage

- Unlimited storage capacity: cloud storage offers limitless storage therefor costs are generally lower per mB - Automatic backup: on a computer a hard disk crash can destroy all your valuable data if it is stored on the device, but if it is in the cloud a computer crash should not affect any of your data - Universal access: you don't carry your files and documents with you on the cloud; they stay in the cloud and you access them whenever you have a computer or mobile and internet connection. All your documents are instantly available whenever you are - Device independence: the user is not limited to working on a document stored on a single computer or network. You can change computer and even change to your mobile device, and the documents follow you through the cloud

How does solid state disks (SSD) work

- Uses electrical signals to change the state of a transistor. The transistor can either be changed to binary 1 or to 0. - SSD do not require physical motion so they have shorter response times. They also do not suffer from physical wear: Sd card uses solid state storage and so are USB flash drives

What is the motherboard

- Within a computer the hardware within the hardware within the system includes the CPU which is situated on a printed circuit board called the motherboard. This links the CPU to the memory and other hardware. - The CPU computes data and uses the motherboard to receive and send signals to things like the hard drives (storage). - A chip on the motherboard is also responsible for holding all of the computer settings, such as Time and Data. Both the CPU and the motherboard have speeds associated with them. - The speed of the motherboard is defined by the bus speed.

Disadvantages of cloud storage

- You need a reliable Internet connection - especially if you are handling large files You are relying on someone else to keep your files safe - Moving from one provider to another can be difficult - There can be data ownership issues if your provider is sold to another company - when Facebook bought Instagram content transferred a 'license to use' that content to Facebook - without the users' express consent - The user loses control over what happens to the data as this is managed by the cloud service provider - Cloud storage will not work as well with low-speed connections. - Even on a very fast connection, web-based storage can sometimes be slower than accessing a data stored on a desktop or laptop computer

What is the arithmetic logic unit

A major component of the central processing unit of a computer system. All routinely performs the following: - logical operations (these include AND, OR, NOT) - bit-shifting operations (shifts the positions of bits by a certain number of places to the right or left which is considered a multiplication operation - arithmetic operations (refers to bit addition, subtraction, multiplication, division)

Define Hardware

A name given to the collection of physical 'things' that, when put together in a certain way, form a system. The physical devices that a computer is made up of are called the computer hardware.

How does optical storage work

In Optical storage, pits and grooves in a flat surface provide a reflection for a laser, a light sensor then assigns a binary 1 or 0 depending on the light intensity

How does the magnetic storage work

In magnetic storage, magnetic material is given a polarity. That polarity is then read and depending on the direction is output as a binary 1 or a 0

What are smart meters

It is an electronic device that records consumption of electric energy in intervals of an hour or less and communicates that information at least daily back to the utility for monitoring and billing (measures the gas and electricity you are using and displays this on a handheld device e.g a phone)

Role of memory management

Keeps track of memory usage and decides which process will get memory, when and how much.

Role of periphery management (Input/ output management)

Manages all the input and output devices, including all peripherals (a piece of hardware that connects to a computer e.g a mouse, keyboard, printer or scanner). Opens, closes and writes to peripheral devices.

Role of processor management

Manages the use of the processor resources therefore allows multiple applications to run at the same time. The means the OS makes it possible to run several programs at once.

Role of security - spyware protection

Programs that secretly record (monitor) and collect information on what you do on your computer

Why is secondary storage required

Secondary storage is the place where software and data are kept when not in use. It is a non-volatile storage mechanism in the CPU unlike RAM which is volatile and therefore data and program files can be stored here when the power supply is turned off and won't lose it's content.

Role of disk organisation utilities - formatter

Storage drives need to be formatted to be compatible with an OS. The OS usually formats storage media when it is connected to the computer. It is often the case that a storage drive cannot be compatible with both Windows and Mac OS X.

Explain the Fetch - Execute cycle

The CPU continuously reads instructions stored in main memory and executes them as required: - fetch: the next instruction is fetched to the CPU from main memory - decode: the instruction is decoded to work out what it is - execute: the instruction is executed (carried out). This may include reading/writing from/to main memory.

Role of maintenance utilities - automatic uploading

The automatic update utility makes sure that any software installed on the computer is up-to-date. For any software already installed on the computer, the automatic update utility will regularly check the Internet for updates. These will be downloaded and installed if they are newer than the version already on the computer.

Effect of clock speed on CPU performance

The faster the clock, the more instructions the processor can complete per second, but there are limits to how fast a CPU can run. If the clock tells the CPU to execute instructions too quickly, the processing will not be completed before the next instruction is carried out. It can also over heat, because when you increase clock speed more power is consumed.

Define software

The programs that run on a computer are called the software.

Role of maintenance utilities - file backup utilities

This allows the user to restore the system to a previous state which is saved as a backup. This is only usually used if a system malfunctions e.g if data is lost