Computer Science
- Created by: AOconnor
- Created on: 13-05-18 17:53
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- Computer Science
- Memory
- Virtual
- Sections of secondary storage temporarily used when RAM is full
- Volatile and slower than RAM
- When CPU needs data from it, the OS loads it into RAM first (quicker access)
- RAM
- Acts as temporary store for program instructions and data (volatile)
- Can be accessed in any order
- DRAM
- Used in RAM modules
- Cheaper but slower and requires refresh signal to retain data intact
- SRAM
- More expensive but quicker and doesn't require refresh signal
- Used in cache
- ROM
- Can be accessed in any order
- Data cannot be changed, edited or overwritten
- Non-volatile
- Stores key instructions like BIOS and MAC Address
- Virtual
- Operating System
- Link between hardware and software and user
- Allows user to access applications
- Allows CPU to communicate with peripheral devices and memory
- Functions
- Provides GUI
- Ease of use without having to enter commands
- User management
- Allows more than one user to log in to system with their own levels of functionality and preferences
- Manages memory
- Allocates sections of memory to CPU and memory modules
- Device driver
- Allows OS to control and communicate with peripheral devices
- File management
- Allows users to organise work into files
- Provides GUI
- Link between hardware and software and user
- Utility Software
- Performs specialised tasks that support OS
- Encryption software
- Scrambles data and renders it uselss when intercepted unless you have a key to decrypt it
- Defragmentation software
- Analyses data and how it is stored and then rearranges it into a more logical sequence
- Allows faster access
- Analyses data and how it is stored and then rearranges it into a more logical sequence
- Compression software
- Reduces file size so they can take up less space
- Lossless reconstructs data without data loss
- Lossy permanently removes data like duplicated elements
- Reduces file size so they can take up less space
- File backup
- Restores data to pre-damaged state if system fails
- Regularly copies important files to external storage
- Incremental only copies data that has been edited since the previous backup
- Full backup copies all important files
- Regularly copies important files to external storage
- Restores data to pre-damaged state if system fails
- Encryption software
- Performs specialised tasks that support OS
- Network Topologies
- Arrangement of computer and network devices in a physical or logical topographical structure
- Star
- Server in centre and each device is connected to it
- Server directs data transmissions between nodes
- Advantages
- Failure of one device doesn't affect rest
- Easy to add new nodes
- Data can be directed to specific address
- Reduced data traffic
- Disadvantages
- If server fails, so does network
- extensive cabling and knowledge needed
- Server in centre and each device is connected to it
- Mesh
- Every device is connected to every other device
- Network traffic is shared between all devices
- Advantages
- Devices share network load (runs smoother)
- Adding devices doesn't affect speed
- If one device fails, rest are unaffected
- Disadvantages
- High level of expertise needed for management
- Extensive cabling
- Hard to add new nodes
- Every device is connected to every other device
- Star
- Arrangement of computer and network devices in a physical or logical topographical structure
- Memory
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