Learning unit 8 Flashcards
One physical machine provides virtual environments for applications using
-Application virtualization
-Desktop virtualization – also called client-side virtualization
Explain application virtualization and desktop virtualization
-Application virtualization:
an application can be made available to users without having to install the application on the user’s computer
-Desktop virtualization:
One computer provides multiple desktops for users
Each virtual desktop is contained in its own virtual machine
What is the main difference between the hypervisors?
Main difference being whether the host computer has its own OS
Differentiate between Hypervisor Type 1 and Hypervisor Type 2
-Type 1 (Bare-metal hypervisor) :
installs on a computer before an OS ; partitions hardware computing power into multiple VMs
Type 2 (Hosted hypervisor) :
installs in host OS as an application; not as powerful as Type 1 because it is dependent on the host OS
What are the cloud computing deployment models?
-Public cloud
-Private cloud
-Community cloud
-Hybrid cloud
Explain the various cloud computing deployment models
Public cloud = services are provided over the Internet to the general public
Private cloud = services are established on an organization’s own servers
Community cloud = services are shared between multiple organizations, but not available publicly
Hybrid cloud = a combination of public, private, and community clouds used by same organization
All cloud computing service models incorporate the following element
-Service at any time
-Elastic services and storage
-Support for multiple client platforms
-Measured service
What categories are cloud computing service models divided into?
-IaaS (Infrastructure as a Service) :
the customer rents hardware, including servers, storage, and networking
PaaS (Platform as a Service) :
the customer rents hardware, operating systems, and some applications that might support other applications installed
SaaS (Software as a Service) :
the customers use applications hosted on the service provider’s hardware and OSs
Applications are provided through an online user interface
XaaS (Anything as a Service or Everything as a Service) :
Cloud can provide any combination of functions
Define VDI (Virtual Desktop Infrastructure)
The technology used when a hypervisor on a server in the cloud presents a virtual desktop to a client computer:
The VDI virtual desktop is presented to the user on one of the following
-Thick client or fat client – regular desktop computer or laptop
-Thin client – computer has a regular OS but comparatively little computer power
-Zero client ( dumb terminal) does not have an OS and just provides a user interface
Two approaches to VDI
-Persistent VDI :
the user owns the virtual desktop, which can be customized for the user and saved for future use
-Nonpersistent VDI :
the user receives a desktop from a pool of desktops; each time the user signs on, she gets a desktop that reverts to its original state
What is a laser printer?
A type of electro-photographic printer that uses mechanical, electrical, and optical technologies
How laser printers work:
-Toner is placed on an electrically charged rotating drum called the imaging drum
-Toner is transferred onto paper as it moves through the system
Seven steps in laser printing:
- Processing the image: bitmap of final page is stored in memory
- Charging or conditioning: drum surface is charged to -600 V
- Exposing or writing: laser beam writes -100 V image to drum surface
- Developing: toner is applied to the surface of the drum
- Transferring: the transfer roller puts a positive charge on the paper to pull the toner from the drum and onto the paper
- Fusing: fuser assembly uses heat and pressure to fuse toner to paper
Cleaning: drum is cleaned of residual toner and charge
Color laser printing
Writing process repeated four times, one for each toner color
What is a duplex printer?
A printer that is able to print on both sides of the paper it uses a duplexing assembly, which turns the paper around and draws it back through the printer
part of routine printer maintenance
-Clean outside of the printer with a damp cloth
-Do not use ammonia-based cleaners
-Clean the inside of the printer with a dry cloth
-Do not blow out toner with compressed air
Two safe tools for printers
-Toner-certified vacuum cleaner
-Extension magnet brush
Printer maintenance kits include
-Specific printer components
-instructions for performing maintenance
-Tips for how often maintenance should be done
-Special tools or equipment
Types of printers for desktop computing:
-Laser
-Inkjet
-Impact
-Thermal
-3D
Overview of inkjet printer technology
-Uses a type of ink-dispersion printing 4
-Print head moves across paper
-Different types of inkjets form droplets of ink in different ways
3 reasons impact printers are still in use:
-Continuous tractor feed allows event and data logging
-Can use carbon paper: print multiple copies at the same time
-Extremely durable
Two types of thermal printers
-Direct thermal printer
-Thermal transfer printer
Explain Thermal transfer printer
Uses a ribbon that contains wax-based ink
Heating element melts ribbon onto thermal paper
Used to print receipts, bar code labels
