General Flashcards
What does I/OPS measure?
Storage device performance. Input/Output Operations Per Second. A measure of maximum device performance.
HDD up to 200 IOPS
SSD up to 1 Million IOPS
What is the OSI model?
Open Systems Interconnect (OSI) Model - A way of visualising and splitting network communication via 7 layers:
- Physical Layer - hardware
- Data Link - sends data packets from network to the hardware
- Network
- Transport
- Session
- Presentation
- Application - manages communications between applications, supports protocols like HTTP, SMTP (Email), FTP, data is human readable at this level.
What does logically mean?
As opposed to “physically”, done virtually. E.g. drives can be separated logically from each other using software as opposed to physically segregated by wires.
Using software to perform the jobs of hardware virtually - like SDN (Software Driven Networking - an example of managing networks logically as opposed to physically)
What is a SAN network?
Storage Area Network - centralised storage facility that generally uses its own private high speed network to handle the high data transfer rates required.
Which OS version does x86 refer to?
x86 refers to 32-bit OSs. As such 32-bit apps are installed in \Program Files (x86)
x64 refers to 64-bit OSs. Installed in \Program Files
Can a 32 bit OS run a 64 bit app/programme?
No. A 64 bit OS can run 32-bit apps but not vice versa (too many bits to handle).
What is ARM? And some features of ARM architecture.
A set of CPU architecture designs created by Arm Ltd. and licensed to other companies/manufacturers that build them.
Traditionally small form factor but very efficient. ARM CPU’s are generally used in IoT/Mobile devices.
Low TDP (Thermal Design Power) - don’t produce much heat.
Advanced RISC Machine (ARM).
In a dual core processor how many memory caches are there typically?
2x L1 caches - smallest memory size but fastest speeds
2x L2 caches - bigger memory than L1 but slower speeds
1x SHARED L3 cache - biggest memory, slowest speed
So there are 5 caches in a standard dual core processor/CPU.
What is multithreading (called Hyper-Threading Technology (HTT) by Intel)?
One CPU acting like two (but nowhere near as fast as using two would be). Increases the throughput of the processes going through the CPU (multiple threads instead of single thread).
A thread is a sequence of instructions given to the CPU.
Requires an OS that supports it as well as the app to support it.
What are threads in relation to the CPU?
Threads are sequences of instructions fed to the CPU. Like using multiple lanes on a motorway - if one is congested then a different thread/lane can be used as to not cause a massive traffic jam/time delay.
What is an Ampere/amp/A?
The rate of electrons moving past a point per second.
What is a Watt/W?
A measure of power consumption.
Volts (V) * Amps (A) = Watts (W)
How do you calculate wattage?
Volts (V) * Amps (A) = Watts (W)
How do you size a PSU wattage for a PC?
Sum the wattage of all components and double that number, this allows for PC expansion/upgrades.
What are the 3 voltages (Voltage Rails) of DC that a PSU converts the 240V AC into for the PC components?
3.3v, 5v, 12v Direct Current
