Paper 1 Flashcards
(30 cards)
Control Unit (CU)
¬ executes program instructions by following FDE cycle
- controls data flow inside CPU to registers and outside CPU
- Overall control of CPU
Program Counter (PC)
holds memory address of the instruction for each cycle
cache
¬ very fast memory but slower than registers.
- Stores regularly used data to access quickly.
- low capacity but expensive
- which means more cache improves the performance of the CPU
- the bigger the cache size,the more data can be stored closer to the CPU.
Memory Address Register (MAR)
holds the memory address about to be used by the CPU, which can point to specific data or CPU instructions
Memory Data Register (MDR)
holds the data or instructions fetched from memory or waiting to be written to memory
Arithmetic Logic Unit (ALU)
¬ carries out calculations and logical operations.
- contains accumulator which is used to store intermediate results and calculations
clock speed
¬ the speed which instructions are executed in cycles per second.
- measured in hertz
higher rate of clock speed
the higher the rate clock speed, the greater the number of instructions that can be carried out per second
core
-it can independently perform or process all computational tasks.
- more cores = the more instructions it can carry out at once so the faster it can process a batch of data
Random Access Memory (RAM)
¬ main memory
- volatile (loses data when off)
- more RAM = better performance
- more programs can run at the same time -multitaksing
- stores: applications, GUI, OS
Read Only Memory (ROM)
¬ CPU reads instructions from ROM
- non-volatile (keeps data when off)
- smaller capacity
- stores: BIOS
virtual memory
Area of secondary storage used by the OS as extra RAM
Fetch-Decode-Execute cycle all steps
1# copy memory address from PC to MAR
2# copy instructions stored in MAR to MDR
3# increment PC to point to address for next instruction
decode
the instruction in the MDR is decoded by the CU . The CU may then prepare for the next step
execute
the instructions is performed this could be load data from memory, write data to memory ,do a calculations or logic operation
secondary storage
¬ where data is stored when not in use
- non- volatile
- (HDD, SSD)
- read / write speeds much slower than primary storage
why secondary storage used
Secondary storage is non-volatile , long-term storage. It is used to keep programs and data indefinitely.
magnetic storage
advantages and disadvantages
Advantages
- LARGE capacity (3TB)
- low cost
- fast read / write time
Disadvantages
- not very portable
- can be damaged
Hard Disk Drive (HDD)
- portable HDDs back up and transport large data amounts
- long lasting (reliable)
- can be damaged by dropping
¬ traditional internal storage for laptops / PCs
SSD advantages
- don’t need defragmentation
-faster
-more shock- proof
-don’t make any noise
optical discs advantages and disadvantages
- cheap per GB
- portable
- robust (can easily be scratched though)
- slow transfer speed compare to SSD
Local Area Network (LAN)
¬ covers small geographic area located on a single site
LAN has own infrastructure
Wide Area Network (WAN)
¬ covers large geographical areas , WAN uses external/shared infrastructure
cloud backup storage
Advantages
Data Protection: Keeps your data safe from loss.
Accessibility: Access backups from anywhere.
Automatic Backups: No manual effort needed.
Quick Recovery: Fast data restoration.
disadvantages
Internet Dependency: Needs a stable connection.
Cost: Ongoing fees can add up.
Security Risks: Potential for data breaches.
Speed: Large backups/restores can be slow.
what affects wireless network performance
-distance from Wireless Access Point (WAP
-physical objects (walls)
- interference from other devices
- weather
router
connects two networks together (LAN and WAN) transmits data between them
* Receive packets
* transmitting packets
Assign IP addresses to nodes/
