in terms of installing a package, what is a
required package
this is a package that is needed to make the selected package work
in terms of installing a package, what is a
dependent package
the required packages of the selected package may also have required packages
what is the term for this
how are
software packages installed / uninstalled
this process is handled by a
package manager
explain the concept of
shared packages
this concept is where two different pieces of software make use of a seperate software package
notes
- the software package used can be built by the software developers or be third-party
- this concept brings with it advantages and disadvantages
name 3 benefits of
shared packages
the benefits of this include:
- saves resources - since the package will not be held inside the any selected package, it means it can be installed once for any other package to use, hence saving disk space
- consistency - if a package is known to be stable then it can be used again without fear of unexpected behaviour
- single point of failure - usually a disadvantage but in this case is the opposite. because the package is not held inside the selected package it means that any bugs or vulnerabilities found can be rectified once without every software package having to update or alter their own packages
name 2 disadvantages of
shared packages
the disadvantages of this are:
- dependency hell - known as dll hell on windows, is a problem where two application programmes require the same package but different versions. Updating or reverting the package causes one of the application programmes to stop working
- package trees - no matter how much of the package you use the full package must be installed. the problem lies in that that package may have its own required packagaes and so on. the problem is you pull in a lot of outsourced code and your application becomes bloated
what does
package numbering
ensure
this helps ensures that a selected software package will always run with a particular version of a package
what three key peices of information could
package numbering
convey
this can convey:
- major version - represented as the first number 10.x.x. can tell developers using the package that any change made to the number represents code breaking changes
- minor version - represented as the second number 10.5.x. can tell developers that minor changes have been made but should have little or no change on the software packages using it
- security and bug fixes - represented as the third number. can tell developers that improvements have been made to security and the code but should have little or no change on the software packages using it
what has driven the rise of
software packages and package managers
this has been driven by the fact that software is becoming even more complex and relying on many configurations and other software. this is especially the case on linux
note
it was once the case that administrators would handle all configuartions of an installation. however, as mentioned above software has become more complex in many ways
what is a
software package
this is an archive file that contains the software itself as well as information about any configurations or packages it relies on.
the software package can then be used by the corresponding package manager to install / uninstall the package
linux distributions can be based on other linux distributions
briefly describe what this means
if a distribution is based on debian for example then it will make use of the debian package file format (.deb). and use the corresponding package manger in this case Advanced Package Mangager (APT).
a distribution based on RPM for example cannot install or use debian packages
what does the accronym
APT
stand for
this stands for
Advanced Package Manager
what is
Advanced Package Tool (APT)
this is the package manger that works with debian package file types. It is used to automate the download, update and install of debian packages that are held inside a repository
what is the outcome of typing
sudo
with another command
using this grants you temporary ‘root’ (administrator) privileges, this is usually used when we need to make any changes to the system
what is the outcome of typing
apt update
on a debian based system
this downloads and updates the latests package information using the configured sources. This should be used before installing any software to ensure you will get the latest version (requires sudo)
what is the outcome of typing
apt upgrade
on a debian based system
this is used to upgrade all installed packages to the latest version (requires sudo)
what is the outcome of typing
Apt search package name
on a debian based system
this will search for the entered package
what is the outcome of typing
Apt install package name
on a debian based system
this will install the entered package (requires sudo)
what is the outcome of typing
Apt remove package name
on a debian based system
this will uninstall the entered package
what is the outcome of typing
Apt show package name
on a debian based system
this will show you information about the entered package such as:
- Name and description
- Current version
- Name of maintainer and url about the software
- List of dependencies and the version numbers required
- Packages that will break the entered package
what is a
repository
this is a place on the internet where software packages can be submitted and stored.
package mangers will access this to install or update packages
how do
package mangers know where to find repositories
on the install of a linux system the address of these are configured and stored so that they can be used by package managers
name the two ways in which you can
view the repositories source URL
this can be found by:
- Terminal - Sudo apt update
- GUI - /etc/apt
what is the outcome of
typing a repositories source URL into a browser
by doing this you can navigate all the repositories via the browser and view their contents
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Topic 1 - What is an operating68
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Topic 2 - Installing an operating32
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Topic 3 - Installing and running software28
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Topic 4 - Shells52
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Topic 5 - The command-line interface138
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Topic 6 - Scripting and archiving106
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Topic 7 – Structure of an operating system68
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Topic 8 – Processors and hardware68
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Topic 9 – Processes and scheduling92
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Topic 10 – Services and daemons92
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Topic 11 – Context switching92
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Topic 12 – Memory management116
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Topic 13 – Input/output Contents140
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Topic 14 – Files and directories82
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Topic 15 – Disk management124
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Topic 16 – Users and security84
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Topic 17 – Booting and configuration62
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Topic 19 – The operating system zoo40
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Topic 20 – Virtualisation68
