ocr gcse computer science paper 1

• The CPU, or central processing unit, is a microprocessor located on the motherboard.
• The purpose of the CPU is to process data and instructions and to control all the other component parts of the computer such as hard disk, DVD drive, sound system, graphics system.
• The CPU goes through a process called fetch-decode-execute cycle when it's carrying out an instruction.
• Drone warfare has become an increasingly important part of modern military doctrine.
• Self-driving cars are programmed to prevent deaths, but there are other machines programmed to cause them.
• Unmanned robots patrol the skies above conflict zones.
• Some drones merely collect information and transmit it back to be analysed, whereas others can launch missiles at the push of a button or with no input at all.
• The instructions are fetched from the main memory, then decoded by the control unit, finally executed and then the cycle repeats.
• The instructions are provided by a computer program.
• The four common components of the CPU are: ALU(Arithmetic Logic Unit), Control Unit, Cache, and Registers.
• The ALU handles the data that is processed inside the CPU, it has two types of processing: Arithmetic operation and Logic operation.
• Less storage space is needed.
• If a file is broken up (‘fragmented’) across too many separate memory sectors, it becomes difficult for the hard disk to access all of the pieces of the file in a timely manner.
• This can make the computer appear to seem running slowly.
• By rearranging the files so they are stored sequentially (next to one another) the utility ensures that the computer runs quickly and efficiently.
• Faster download and upload of files.
• To prevent this, defragmentation utilities juggle the contents of memory sectors around to keep the files together as much as possible.
• A compression utility makes the file size smaller.
• Better performance is achieved when streaming videos or audio.
• The Control Unit takes care of how, where, what and when data goes, it has three main jobs: controls the way data moves around the cpu, executes the instructions provided by the program, and controls and monitors the flow of data between the cpu and other components.
• Cache is a small amount of high-speed RAM that temporarily holds data that has frequently or recently been used, it is used to speed up the processing time as it is much faster than RAM, but slower than registers.
• Cache has 3 different levels: Level 1 is the fastest but lowest capacity/holds the least amount of data, Level 2 is slower than level 1 but larger capacity/holds more data than level 1 but less than level 3, Level 3 is slowest but has the most capacity/can hold the most amount of data.
• Registers are small but very fast type of memory in the CPU that holds temporary data whilst a software program is running, it is much faster to shift data in registers than cache or RAM.
• A network monitor records data packet in real time, and can alert to unusual network traffic or a server being particularly busy, which may indicate a malware or virus.
• Penetration testing involves hiring professional hackers to attempt to gain access to the network.
• System logs are records of everything that takes place on the network, including login attempts, file accesses, and changes to data.
• Tasks of the kernel include loading/unloading applications from memory, scheduling tasks to run efficiently on the CPU, memory management, file storage to and from secondary storage devices, and file management.
• User interface allows a person to interact with the computer.
• Operating system is the core software that controls how a computer operates, examples include Windows, Linux, Unix, iOS, Android.
• Anti-malware software is designed to detect and remove programs designed to detect keystrokes or malware that quietly allows remote control of the computer.
• A firewall sets the rules for how data packets can enter or leave the network, and can block access to certain IP addresses.
• Encryption is the process of scrambling a message of data in such a way that only the person or computer knowing the correct key can read it.
• Network forensics is the process of determining what occurred to prevent future attacks.
• The operating system has 4 main parts: the kernel, device drivers, user interface and system utilities.
• Purposes of the operating system include controlling the hardware of the computer system, managing software, providing security, providing a user interface, and managing files and folders.
• Types of user interface include menu interface, command line interface, and graphical user interface.
• MDR(Memory data register) holds data that is being transferred to or from the memory, MAR(Memory address register) holds the memory location of data that needs to be accessed, PC(Program counter) contains the address of the next instruction to be executed, AC(Accumulator) stores the results of ALU, IR(Instruction Register) contains the next instruction to be run.
• The disadvantages of using a LAN network include network failure and slow service.
• Data can be transmitted very quickly between network computers.
• The internet is a worldwide collection of computer networks that enables communication on an international scale.