Layers Of Defence Mac OS

Home > Articles > Apple > Operating Systems

1. The Layers of Mac OS X: Aqua

In Mac OS 9, the System Folder was the OS. Except for a few invisible files (such as the Desktop files), all OS files were in the System Folder where they were easily accessible. In Mac OS X, the entire Unix layer remains largely invisible from the Aqua Finder. Thus, Mac OS X has a sort of secondary OS underneath the visible OS. Layered Security vs. Defense In Depth. Layered security and defense in depth are two different concepts with a lot of overlap. They are not, however, competing concepts. A good layered security. Aug 08, 2011 Also part of Mac OS X are the core services layer and the application services layer. Together with the kernel and hardware, these layers form what computer engineers call a stack. A stack is just a way to conceptualize the relationship of the various layer of a computer's software and hardware. In short, Layer 2 allows the upper network layers to access media, and controls how data is placed and received from media. Hardware—the things you can actually physically touch—exist at Layer 1 (Physical). This layer converts the binary from the upper layers into signals and transmits them over local media.

Presentation layer is the second last layer in the OSI model responsible for services like data compression, encryption, decryption, data conversion etc.

There is more than one way to think about dividing up a pizza. First, there is the familiar method of dividing it into slices. Alternatively, you could divide it into layers: topping, cheese, sauce, crust. Theoretically, you could also divide it into its basic ingredients: flour, water, tomatoes, garlic, milk. Each method makes a different contribution to your enjoyment of the pizza. The first method (slices) is best when you're getting ready to eat the pizza; the second is best when you are deciding what to order (such as pepperoni with extra cheese); the third is best if you are concerned about nutrition (needing to know the exact ingredients to calculate calories).

The same is true for Mac OS X. There are multiple ways to look at it and take it apart. Each way makes its own contribution to your understanding of the OS. In this chapter, I look at the major ways to 'take apart' Mac OS X. Having at least a minimal knowledge of Mac OS 9 will help, as I occasionally make comparisons between the two OS versions. But even if you've never used Mac OS 9, you'll be able to follow along.

In This Chapter

The Layers of Mac OS X: Aqua

The Layers of Mac OS X: Application Environments

Cocoa
Carbon
Classic
Java
Putting it together

The Layers of Mac OS X: Graphics Services

Quartz
Multimedia: OpenGL and QuickTime

The Layers of Mac OS X: Darwin

Mach
BSD (Unix)

Domains: An Overview

System domain
Local domain
User domain
Network domain

The Libraries of Mac OS X: /System/Library

Core Services
CFMSupport
Extensions
Fonts
Frameworks
PreferencePanes
Printers
QuickTime
ScreenSavers
Services
Sounds
StartupItems

The Libraries of Mac OS X: /Library

Application Support
ColorSync
Contextual Menu Items
Desktop Pictures
Documentation
Fonts
Internet Plug-Ins
Modem Scripts
Preferences
Printers
Receipts
StartupItems

The Libraries of Mac OS X: Users/'Home'/Library

Application Support
Caches
Favorites
Font Collections
Fonts
Internet Search Sites
Keychains
Preference Panes
Preferences
Application-specific folders

Fonts in Mac OS X: Font Formats

TrueType fonts
PostScript fonts
OpenType fonts
Bitmap fonts
Identifying font formats

Fonts in Mac OS X: Working with Fonts

Font Panel window
Font smoothing and Mac OS X
International language support: basics
International language support: troubleshooting
Font utilities

The Layers of Mac OS X: Aqua

Aqua is the name given to what most users think of when they think of Mac OS X: the user interface, the Finder, the Dock, the windows, the translucent buttons, the high-resolution icons, the menus, and all the rest. Many users may never explore Mac OS X beyond its Aqua layer.

From this perspective, a user upgrading from Mac OS 9 will feel quite at home, at least initially. Much still works the same way. You still double-click icons in the Finder to launch them; you still choose the Save command from an application's File menu to save a document; you still open a folder icon to see its contents.

But you will soon notice some significant differences: a new column view, a very different Apple menu, the Dock. I discussed the basics in Chapter 3, when I presented an overview of Mac OS X.

Introduction
LLDP provides an alternative to proprietary protocol from Cisco CDP with the big advantage to be standardized on a large number of devices. Like CDP, LLDP allows network equipment to communicate with each other by indicating, as example, their position on a switch or IP address. The use and functioning of LLDP is close to that of CDP, I don’t want to go into detail. Information is available on this previous post.

In summary you can recover information to identify the location of a computer station on a switch without having to follow the wiring and even use this information in tools like Absolute Manage.

Compile openlldp for Mac OSX
As often, there are several tools to integrate the LLDP. The solution recommended in this post is to compile OpenLLDP with Mac OS X and use the application to retrieve information about the network location.

Before you begin this step, it is necessary to install Xcode from the Mac App Store and the “Command Line Tools”. These are in the Xcode preferences in the “Downloads”.

– Download the last version of openlldp from the website of the project and uncompress the files

– Go with the Terminal to the openlldp folder where are the sources of the application

Layers Of Defence Mac Os Pro

– Prepare the compilation with the configuration command

– Start the compilation with the command “make”

– It is possible (but not required) to automatically install openlldp files

Usage
The OpenLDAP project is composed to two distinct applications :

lldp is a daemon to start at boot who will capture LLDP frames arriving on the client workstation.
lldpneighbors is the tool to find the network equipment that is connected to the client.

Layers Of Defence Mac Os Catalina

Since the software is in Alpha version, it’s best to create a script that will handle lldp launch, display the result with lldpneighbors and then exit the process lldp. The precautionary principle.

It should not forget that the frames are sent every 30 seconds by default, so it’s necessary to leave lldp launched long enough to capture packets. If your devices are configured to send lldp network information with more time, it’s needed to adapt your scripts.

Layers Of Defence Mac OS