unit 2 Flashcards
State and define 3 transmission protocols
HTTP - Used to control the transmission and reciving of webpages
HTTPS - HTTP but encrypted
FTP - Used for transfering files
TCP - Ensures data is recived but can be slow
What does a real time OS do?
Real time operating systems process data as soon as it is set to be processed. This is useful in time sensitive applications such as aircraft control or in self driving cars
Name the types of Operating systems
Real time, Single user, Multi user
What is a single user operating system
Single user OS’s are designed to be used by one person at a time, there are not really any current uses for them except in low end devices such as feature phones
What is a multi user operating system
A multi user operating system is designed so multiple people can use the machine at the same time - meaning multitasking support is critical. Most operating systems that you use, including windows is a multi user OS
What is the role of the kernel
The kernel is a core part of an operating system - it manages interrupts, CPU / Memory allocation, APIs for accessing files and device drivers
What is an interrupt
an interrupt is an instruction that changes what the system is working on, eg a mouse moving
What are device drivers
Pieces of software that allow the operating system to communicate with hardware, such as a gpu.
What is utility software
Utility software is software designed to run along side the main OS and perform maintenance tasks, such as security of backing up software
What is application software
Application software is software that the user will use to do whatever they want - eg Firefox or excel
Name the 5 types of data proccessing
Aggregation - Large amount of data processed into one or more summaries
Analysis - When meaning is extracted from data
Conversion - Conerting from one form to another, for example a json file to a pandas object
Reporting - Following the data processing functions so that managers can understand the current state
Sorting - Describe sorting without using the word sort :^)
What is the difference between NUMA and UMA
UMA is a technique for sharing RAM where each CPU can
access any of the memory at the same speed. Individual
CPUs can have their own cache memory allocated in the
shared RAM. UMA systems share the same memory bus.
NUMA is an alternative technique for sharing RAM
whereby each CPU can have some RAM allocated as local
memory as well as sharing other (foreign) parts of the RAM
with the other CPUs.
What is the difference between simplex, half duplex and full duplex
Simplex: only one direction, could be used in something like a sensor reporting to a computer
Half duplex: Can go both ways but cannot do both simultaneously, WiFi uses this as well as devices like walkie talkies
Duplex: can go both ways, at the same time. Used in ethernet and other high bandwidth cases
What is a parity scheme
Parity schemes are used in the RAM to check the accuracy
of each byte. A byte has 8 bits and using a parity scheme
another bit is allocated to the byte to help check for errors.
It does this by counting the number of bits set to 1 in the
byte then using the parity bit to make the number of Is an
odd or even number.
An odd parity scheme would use the parity bit to make the
number of Is in the byte into an odd number. For example
the parity bit for 01101110 would be 0 because there are
would be 1 because there 6 (even number) bits set to I so
another I makes it an odd number of Is.
If 01101110 0 (odd parity) was transmitted and a corruption
occurred, 01101010 0 could be received. As this has an
even number of Is (i.e. 4), the receiving device would
detect the error and request a retransmission.
Similarly, an even parity scheme would use the parity bit
to make the number of Is in the byte into an even number,
for example the parity bit for 01101110 would be 1 and
very good at detecting multiple bit errors, since if two bits
are received as Os rather than Is, the parity will remain
correct, despite the error.
What is a checksum
Checksums are used to check for errors, this is done by performing a calculation on the transmission before and after sending the data and making sure they match
