Computer System Flashcards

Riley Loades
Flashcards by , created 2 months ago

GCSE Computer Science (Paper 1) Flashcards on Computer System Flashcards, created by Riley Loades on 05/12/2019.

Riley Loades
Created by Riley Loades 2 months ago
Computer Systems
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Question Answer
Explain the Fetch-Decode-Execute Cycle? 1) The memory address is copied from the Program Counter to the MAR. 2)The instruction at that address is copied from the MAR to the MDR. 3)The instruction in the MDR is decoded by the CU. 4)The instruction is then executed/performed. (The Program Counter increments each time, to point to the address of the next instruction, ready for the next cycle)
Explain Cache in detail? Cache is very fast memory in the CPU, faster than RAM, slower than registers. it contains regularly used data so the CPU can access it quickly, the next time it is needed. The CPU checks cache first to see if it is there, if not then it checks RAM. L1 Cache - Fastest/Smallest L2 Cache - Slower/Larger L3 Cache - Slowest/Largest
Explain RAM and ROM? RAM can be read and written to, and is the main memory of the computer, storing any data that is currently being used. RAM is volatile, so it needs power to keep its data. ROM can only be read to, and contains all the instructions the computer needs to properly boot up, these instructions are called the BIOS (Basic Input Output System). ROM is non-volatile, so it keeps its content without power.
Explain Virtual Memory? Virtual Memory is secondary storage that is used as extra RAM, and stores any data that hasn't been used regularly from RAM. To read any data in virtual memory, the data must be moved back to the RAM before it can be read, which is slow as it much slower to transfer data from secondary storage than RAM.
Explain the factors in CPU performance? CPU performance is affected by clock speed, number of cores and cache size. Clock Speed - the number of instructions a single processor core can carry out per second. Number of Cores - the amount of instructions the CPU can carry out at once. Cache Size - The larger the size, the more data the CPU can access at a faster rate.
Magnetic Storage High Capacity Reliable Slow Speed Cheapish Poor Portability Long read/write Life
Solid State Storage High Capacity Reliable Fast Speed Pricier Portable Short read/write Life
Optical Storage Low Capacity Poor Reliability Slow Speed Cheapest Portable
Explain the Operating System? The Operating System manages hardware and software. It is a complex piece of software found on most computer systems.
Explain the functions of the Operating System? User Interface - allows the user to interact with a computer system. Peripherals Management - allows communication between software and hardware. File Management - allows the computer to manage files and storage. Memory Management - allows the computer to multi-task by controlling memory resources and the CPU. User Management - allows the computer to manage the security of the system.
Explain Utility system software? Utility system software helps to maintain and configure a computer. There are many different utilities installed with the OS, but more can be installed.
Explain the types of Utility Software? (1/2) Defragmentation - reorganises data on the hard drive to put fragmented files back together. It also moves files to collect all the free space together to prevent further fragmentation. Backup - Full Backup is where every file is copied. It uses a lot of storage, can take a long time to create but is restored fast. Incremental Backup is where only new or edited files since the last backup are copied. It uses less storage, is fast to create but a full system restore is slower.
Explain the types of Utility Software? (2/2) Compression - Lossy compression permanently removes data from the file to limit the number of bits the file needs, reducing its size. Lossless Compression makes the file smaller by temporarily removing data to store the file, then restores it to its original state when opened. Encryption - It scrambles the data to stop third-parties from accessing it. Encrypted data can only be decrypted using a special 'key'.
Explain Open Source and Proprietary Software? Open Source software is freely available source code, that can be legally modified and shared under the same license and terms as the original software. Proprietary software is usually paid for, but doesn't release the source code, it only releases the compiled code that runs the software, and doesn't tell you how the software was made.
Advantages and Disadvantages of Open Source Software Open Source software is free, made for the greater good, can be adapted to fit a users needs, a wide pool of collaborators and can be reliable and secure if community fix problems quickly. BUT Open Source software might have small projects that don't get regular updates, have no warranties for if something goes wrong, have limited user documentation, no customer support other than community forums and has their code free to look at by other competitors.
Advantages and Disadvantages of Proprietary Software Proprietary software comes with warranties, documentation and customer support, a more reliable, well tested software with more reliable, regular updates as their reputation depends on it and usually cheaper for companies than developing their own custom-built software. BUT Proprietary software can be expensive, may not fit the user's needs and may not maintain older software after warranties because they'll want people to buy their latest product.