Computer Systems (Paper 1 & 2) Flashcards
What is hardware?
The physical components of the computer
What is software?
Programmes installed into a computer
What is system software?
Manages the computer and allows to user to interact with it eg operating systems
What is application software?
Software that is downloaded onto a computer eg Microsoft Word
What is the role of the CPU?
It fetches and executes instructions and keeps the computer running
What is the main role of the ALU?
The ALU performs logical and math instructions and also does binary shifts
What is the role of the control unit?
Coordinates all activities taking place in the CPU
What is the role of the clock?
Keeps the CPU in sync and with each ‘tick’ an instruction is decoded or carried out
What is the role of the buses?
They fetch instructions or data from different parts of the computer
What effect does clock speed have on the computer?
The faster the clock, the faster the computer as it can process more instructions however it decreases the lifespan of the computer if the clock goes too quickly
What effect do cores have on the computer?
If the processor has more cores, it can process multiple times faster eg if it had dual core it can process double the original speed
What effect does cache have on the computer?
Cache allows frequently used instructions to be stored closer to the processor than if it was stored in storage or RAM so it allows the computer to run faster
What are the main differences between memory and storage?
- memory is usually volatile and storage is usually non- volatile
- memory is stored closer to the processor than storage
- storage is bigger
What are the three types of hardware storage?
Optical, magnetic and solid state
What are 3 advantages of optical storage?
- Easy to store and carry
- Can be used in multiple devices
- Long Lasting (with proper care)
What are 3 disadvantages of optical storage?
- Require special drives to read/write
- Expensive GB/TB storage
- Can be easily damaged
How does optical storage store data?
It works by reflecting light to read data. Writing to the disk is achieved using a laser beam to record data.
Data is stored in form of tiny pits arranged in concentric tracks on the disk’s surface. Disk’s surface is covered in dents(pits) and flat spots(lands). These reflect the light in different ways. The dents and flat spots represent 0’s and 1’s.
Name 3 examples of optical storage
CD, DVD, Blu-Ray
Name 3 examples of Solid State Storage
USB, Solid State Drives (SSD), SD cards
What are 2 disadvantages of Solid State Storage?
- More expensive than most other storage
- Limited lifecycle (1000 read/write cycles)
What are 3 advantages of Solid State Storage?
- Very fast access speed
- Small and light
- Quiet (no moving parts)
How does Solid State Storage store data?
It consists of transistors that hold their charge when powered off. All start at 1 (on) but when saving data, some are blocked and become 0 (off). This allows data to be stored in binary.
What are 3 disadvantages of magnetic storage?
- Loud (moving parts)
- can overheat easily
- more bulky than SSS
What are 2 advantages of magnetic storage?
- can usually store more data than SSS or optical
- cheaper than SSS
What is cloud storage?
Where the data is stored on a server and can be accessed via the internet
What are 2 examples of cloud storage?
- Google Drive
- Dropbox
What are 3 advantages of cloud storage?
- low maintenance costs
- can be accessed via multiple devices
- easy to upgrade
What are 2 disadvantages of cloud storage?
- more accessible to hackers
- reliant on an internet connection
What is the computer system for input/output?
input - processor - output
l l
memory
l l
storageName 3 input devices
Keyboard, touchscreen, mouse
Name 3 output devices
speakers, printer, screen
Name 3 factors that can affect the performance of a computer
- clock speed
- amount of cache
- number of cores
define secondary storage
Secondary Storage is storage that can store data when there is no power. It cannot be accessed directly by the CPU.
What is RAM?
Random Access Memory. It is volatile and stores programs while they are running
What is ROM?
Read Only Memory. It is non-volatile and holds the setup instructions for the computer
Name the 5 things that the Operating System manages
- processor
- memory
- input / output devices
- applications
- security
What is an embedded system?
An embedded system is an operating system with a specific function within a larger mechanical or electrical system.
What is a non embedded system?
A non embedded system has a more general purpose than an embedded system and can operate multiple varying functions
What happens in fetch in fetch decode execute?
- Address of instruction is fetched from a memory register
- Register incremented so it points to next instruction to be executed
- Instruction put into a special register ready to be decoded
What happens in decode in fetch decode execute?
the control unit decodes the instructions
What happens in execute in fetch decode execute?
- instruction is executed
- depending on type of instruction different things could happen
- eg could involve fetching data from memory or jumping a line in a program
