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Computer Science - Paper 2- Part 1 (Improving Computer Performance (✮Too…
Computer Science
- Paper 2- Part 1
CPU
Info
✮The brain of a computer system
✮ Processes data and information
✮ The architecture describes the main components of the CPU
✮ Processing power depends on clock speed, number of cores and cache type/size
The Control Unit
- CU
✮Main job is to execute program instructions by using the Fetch-Decode-Execute cycle
✮Controls data flow inside CPU and outside
The Arithmetic Logic Unit
- ALU
✮Does all the calculations
✮ It can add, subtract, compare numbers, multiplication and division
✮Preforms logic operations (AND, OR, NOT, binary shift)
✮ Uses registers to store intermediate results of calculations
The Cache
✮ Slower than registers, faster than RAM
✮Stores regularly used data
✮Can be accessed quickly, if data isn't there it fetches it from RAM
✮Low capacity, expensive compared to RAM and secondary storage
Levels
Level 1
Always integrated into the CPU
Level 2
Level 3
The Clock
✮ How fast the CPU carries out instructions
✮Number of clock cycles is the clock speed
✮Send out a signal which cycles between 1&0 at constant rate
Improving Computer Performance
✮Too little RAM. slows the system down
✮More RAM allows makes it faster
✮If there is a sufficient amount of RAM, increasing RAM will not affect performance
✮A GPU can relieve the load on the CPU, allowing it to do other things
✮Basic GPUs are integrated in the motherboard
✮Installing a dedicated GPU (graphics card) will improve performance (good for graphics intensive applications)
Improving CPU performance
CPU Cores
✮More cores, the more instructions which can be carried out
✮Many have 4 or more these days
✮Each core can process data independently
Cache
Size
✮ Larger CPU cache means faster access to data
Type
✮L1, quick because its on the CPU
✮L2, just outside the CPU, second fastest
✮L3, on the mother board, furthest away, slower than the other levels
Clock Speed
✮Higher clock speed means more instructions per second
✮Can be overclocked but is risky if not done properly
✮Can make a CPU overheat, cause a crash or permanent damage
✮Cooling system needed (e.g water cooling)
Fetch/Execute Cycle
Fetch
✮CU fetches the instruction from the memory, using the bus. Thee instruction is coppied
Decode
✮ The copied instruction is decoded by CU. ALU performs the operation
Execute
✮Instruction is preformed
Secondary storage
Info
✮Primary storage = memory areas in CPU
✮Registers, cache, ROM & RAM
✮Primary is volatile
✮Secondary is Non-volatile
✮Isn't directly accessible by CPU
✮Where the data is stored
(Applications, user files, OS)
Read/Write Speed is much slower in secondary than Primary
Types of Storage
✮HDD - Hard disk drive, uses a fast spinning magnetic disc
✮SSD- solid state drive, uses transistors to store data, this store doesn't need defragmentation
✮M.2 Drive, plugs directly into the motherboard, the fastest drive we have, small storage
✮Optical drives, cant be changed once written to, reflects off pits and divets, e.g. Burning a CD (literally) with a laser
✮Cloud Storage - Uploaded directly to internet/ remote server. Normally paid for by a subscription
Pros
✮Accessible from any device
✮Easy to increase storage, lots of storage available
✮Automatic backups
✮Accessible from anywhere
Cons
✮Internet connection needed
✮Upload/downloads speed depends on bandwidth
✮Vunereable to hackers, data leaks, data being sold on
✮Unclear who owns the data
✮Could be expensive in the long term
RAM and ROM
✮ROM, Read only memory
an example of this is: a chip built onto the motherboard which stores the interface for the bios, it is soldered directly onto the motherboard
✮RAM, random access
A volatile type of memory, meaning that it is wiped every time the system ids turned off.
Little ram means a slow computer, amount of ram drastically affect the speed of a computer
Embedded systems
Pros
✮Cheap, small, easy to use, does what is says on the tin
Cons
✮Can't do a lot other than what is meant for
What is it?
✮ Computer hardware with software embedded into it
✮ Focus on dedicated tasks
✮ Require minimal human intervention