Cheatography
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RAM vs Cache Memory
RAM |
Cache Memory |
Fast read and write access |
Faster read and write access |
Volatile |
Volatire |
Used to store data and currently running programs |
Used to store frequently used data |
Necessary as most data is stored on slower storage media |
Resides close to CPU |
Defragmentation of SSDs
SSD uses direct access, so there woudl be no improvement in read times |
May perform "trim" command which imrpoves speed of write operations |
SSD uses NAND based flash memory. Defragmentation may shorten its lifespan. |
FTP vs UDP
FTP |
UDP |
Breaks data into packets |
Breaks data into packets |
Can re-send dropped or damaged packets |
Does not re-send dropped or damaged packets |
Packets can be re-assembled if they arrive out of order |
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FTP not useful for streaming media, as receiving new packets is more important than receiving old ones |
UDP useful for streaming media, as receiving new packets is more useful than receiving old ones |
Floating Point vs Integer
Integer |
Floating Point |
Numbers are stored accurately |
Non-integers can be stored |
Requires less complex processing |
Greater range of numbers can be stored |
Allows for exact representation of 0 |
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Takes up less storage space |
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Von Neumann Architecture
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Clock Manages Fetch/Decode/Execute cycle
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ALU Processes data involving arithmetic and logical operations
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Registers A small/fast/temporary storage addressed by mechanisms other than main memory
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Buses Connects all internal components of a computer
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Cache Memory Fast, easily accessed memory close to the CPU.
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Star Network
If one cable breaks, network will still operate. |
Faults are easy to detect. |
Data has to pass through hub, so it is very secure. |
Easy to add new stations. |
Handshaking
Exchange of signals between devices to establish readiness to communicate |
Example: Establishing a printer's readiness to print |
Packet Switching
Data split into packets |
Each packet can be transmitted on different routes |
Packets may arrive out of order |
More secure than circuit switching |
Makes more efficient use of data lines |
Contains source address, order number of packet and parity bit. |
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Storage Devices
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External HDD Fast data transfer
Cost-effective cost per unit of storage
Portable and can be stored securely
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Third party storage provider Fast transfer(depending on network speed)
Could be more expensive than HDD due to company fees
Data is stored securely
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Flash memory drive Very fast access
Cost effective cost per unit of storage
Very portable
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Magnetic tape Can have very slow access speed
Allows for very large amounts of storage
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Network Protocols
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HTTP Transferring multimedia web pages over the Internet
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DHCP Assigning dynamic IP addresses to devices on a network.
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Data Transmission
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Simplex In one direction only
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Half-Duplex In both directions, but not simultaneously
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Duplex In both directions simultaneously
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Overflow Areas
Physical location of a piece of data is calculated using a hashing algorithm |
Calculation is carried out on the primary key |
Data collision occurs when two items are hashed to the same location |
In this case, the data is sent to the overflow area. |
When there are many hash collisions, access to the overflow area may be slow |
A new hashing algorithm is required and a larger file may be needed. |
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Created By
https://alexhoratiogamedev.blogspot.com
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