1,2a) Systems Architecture/ Computer Systems Flashcards
What does the CPU do?
Processes all of the data and instructions that make the computer work
Describe the fetch decode execute cycle?
(FETCH)
1) Copy memory address from the program counter to MAR
2) Copies the instruction stored in MAR address to MDR
3) the program points to the next instruction ready for the next cycle
Describe the fetch decode execute cycle?
(Decode)
The instruction of MDR is decoded. CU prepares for next step
Describe the fetch decode execute cycle?
(Execute)
Instruction is performed
Eg. Load data from memory
What does the ALU do?
- Does all calculations
- performs logic operations
- contains accumalator register
What does the CU do?
Controls the CPU. Manages fetch,decode,execute cycle
Controls flow of data
What does cache do?
- Very fast memory in CPU. faster than RAM.
- Stores regular used data so CPU can access quickly if needed
- Very low capacity and expensive
What does the register do?
- Holds tiny bits of data needed by CPU
Whats the MAR?
Holds any memory address about to be used in CPU. Points to data or CPU instruction
Whats the MDR?
Holds the actual data or instruction. May be fetched from memory or waiting to be written by memory
Whats the program counter?
Holds memory address of the instruction for each cycle
Whats the accumalator do?
The accumalator stores immediate results of calculations
Whats the clock speed?
Number of instructions of a single processor core can carry out per second
What does a higher clock speed do?
The greater number of instructions to be carried out per second
Whats a negative of clock speed?
Some CPU’S can be overclocked to run a higher clockspeed but if not done properly can overheat and damage system. Water collers are needed
Whats the cache size?
The data storage inside the CPU thats much faster than RAM
Whats a pro of cache?
Gives CPU faster access to more data it needs to process
What are embedded systems?
Computers in a larger system
Examples of embedded systems?
Microwaves,tv,dishwasher
What are embedded systems used as?
Control systems which control machinery to acheive desired result
What is primary storage?
Memory areas of the CPU which you can access quickly eg registers,cache,ROM and RAM.
What is RAM?
Random access memory and is the main memory in a computer. It can be read and written. It’s volatile. Also stores data while being used
What is ROM?
Read only memory and is non volatile.
Contains all the instructions a computer needs to boot up (BIOS)
An example of what ROM does?
CPU reads instructions from ROM to do self checks and set up the computer. Also built in the motherboard
What is virtual memory?
Secondary storage used as extra RAM.
(If ram is full up data that hasnt been used recently moves to virtual memory)
When will virtual memory be needed?
Too many applications used at once
Cons of virtual memory?
Can make computer slower to respond when switching applications
What is secondary storage?
Non volatile. Where all data is stored when not in use
Eg: CD’s and SD cards
Name some types of secondary storage?
Optical(CD’S, DVD’S, Blue Ray),magnetic (tapes) solid state (SSD’S)
What is a hard disk?
Internal storage built in PC’S and Laptops. Data is stored magnetically in small areas of the disk.
What are solid state drives?
Devices with no moving parts. For internal and external storage.
Advantages of HDDS?
- Cheaper
- HDD has higher storage
- HDD haslonger read/write than SSD’s
Advantages of SSD’S?
- Faster
- Don’t need defragmenting
- SSD’S are shockproof
- SSD’S are silent
What are magnetic tapes used for?
Archiving to store huge amounts of data
Disadvantages of optical discs?
- Internet speeds have increased so services like Netflix and Spotify removed optical discs.
- Modern devices don’t have optical discs
- Can be scratched easily
advantages of optical disc?
- Cheap
- Portable
- Won’t be damaged to water
Slowest to fastest on types of storage?
- Optical disc
Memory card
Magnetic tape
HDD - SSD
Cheapest to expensive on types of storage?
- Magnetic tape
Optical disc
HDD
Memory card - SSD
Average capacity lowest to highest on types of storage?
- Optical disc
Memory card
SSD
HDD - Magnetic tape
What are reliable types of storage?
SSD and hard drive
Why do computers need primary storage?
- Low capacity and it is internal storage that can be accessed by the CPU
- Primary storage is much faster than secondary storage
