Unit 6 Resource Management Flashcards
Resources to manage
Primary memory (RAM) Secondary storage Processor speed Bandwidth Screen resolution Sound processor Graphics processor Cache Network connectivity
Primary memory (RAM)
Where all data/programs currently being processed are kept
Effect of primary memory is too limited
Need to use secondary memory = slower Virtual memory problem = can’t load data
Secondary storage
Where data is stored if power is lost
Effect of secondary storage is too limited
No place to save work Limits storage amount Can also prevent the OS from using storage as virtual memory if RAM fills up
Processor speed
Does all calculations in system (calculation/second)
Effect of processor speed is too limited
Take longer to perform tasks
Bandwidth
How much data can be sent at the same time in a certain time frame
Effect of bandwidth is too limited
Movement of data is longer
Screen resolution
Amount of pixels in height x width of display
Effect of screen resolution is too limited
Poorer quality images = harder for user to see correctly
Sound processor
Emits sound
Effect of sound processor is too limited
Slows down overall system Not high quality if part of the system
Graphics processor
Does complex graphics processing
Effect of graphics processor is too limited
Takes longer and limited features if it’s on system
Cache
Instruction that CPU is most likely to request from RAM - speeds up processing
Effect of Cache is too limited
Slower; as CPU will request from RAM (Sluggish)
Network connectivity
Network card connecting to particular type of network media
Effect of network connectivity is too limited
- Limits the way data can be sent/received in a system - Speed
Cores
ALUs; Can do calculations quicker (as they are done simultaneously) if there’s more than one
Types of computer systems
Mainframe (large companies) Servers (Cloud storage) PCs (Companies; schools) Sub laptops (before tablets) Tablets (Portability) PDA’s (Overtaken by smart phones) Digital Cameras (High end photography)
Multi user system
Many users on same machine or connected to same network
Multi programming system
System with different sets of apps installed
Single programming system
Can only run one program/set of programs
Managing primary memory
OS ensures that each program runs in its own allocated space - else problems with security and corruption
Virtual memory
Allows a computer to compensate for shortages of physical memory by temporarily transferring pages of data from RAM to disk storage
Managing secondary storage
Folder structure
Time slicing in multi user system
Set amount of processing time each user gets
Time slicing in single user system
Set amount of processing time each program gets
Interrupt Handling
Execution triggered by the reception of an interrupt (High priority task that needs immediate action)
6.1.7
Check other quizlet
Examples of dedicated OS
iOS 9 for iPads and iPhones Ubuntu Kylin for chinese users
Advantages of dedicated OS
Security; Customisability and modify priorities - delete unwanted elements; shrinking size of OS
Advantages of dedicated OS in an exam
Size; speed; customization
What does abstraction do?
Changes to hardware cannot be seen by users due to abstraction
Drive letter
Letters assigned to physical drives for different properties
Java virtual machine
Interprets binary code for a computers processor to perform instructions
Virtual machine
Software that you can install which allows you to run non native OS
How virtual machine is a form of abstraction
Treats every OS the same and tests software on any platform (platform independent)
PC vs Mobile
Different in Memory; display screen and input devices
Scheduling
Work assigned to resources that complete work
When is scheduling used?
Algorithms with several functions
Why is scheduling used?
In order to process instructions and give them the necessary resources to complete
Policies
What is to be done while mechanism specifies how it is to be done
When is policies used?
The timer construction - limiting the time a process can use the CPU for
Why are policies used?
Flexibility of a system
Multi tasking
Allows user to perform more than one task at a time
When is multi tasking used?
Opening web browser and word at the same time
Why is multi tasking used?
In order to keep track of where you are in tasks and go from one to another without losing information
Virtual memory
Allows computer to compensate for shortages of physical memory by temporarily transferring pages of data from RAM to disk storage
When is virtual memory used?
When storage is a problem
Why is virtual memory used?
As storage is running out
Paging
Swapping the temporary storage space on RAM to hard disk to retrieve other pages - OS needs to retrieve the data that was moved temporarily to disk storage
Paging (simplified)
Used in virtual memory Increase primary memory Memory divided into logged pages Transferred in and out
Interrupts
Signal to processor to indicate an event needs immediate action
When is interrupts used?
When there is a high priority condition that needs immediate action
Why is interrupts used?
In order to allow the OS to conduct necessary protocol to ensure that the action is performing correctly
Polling
Process where computer waits for external device to check for its readiness
When is polling used?
Printers - Computer waits until printer has received next character
Why is polling used?
In order to ensure that tasks are performed correctly and in right order
