Computer Network | Layers of OSI Model

OSI stands for Open Systems Interconnection. It has been developed by ISO – ‘International Organization of Standardization‘, in the year 1974. It is a 7 layer architecture with each layer having specific functionality to performed. All these 7 layers work collaboratively to transmit the data from one person to another across the globe.

1. Physical Layer (Layer 1) :

The lowest layer of the OSI reference model is the physical layer. It is responsible for the actual physical connection between the devices. The physical layer contains information in the form of bits. It is responsible for the actual physical connection between the devices. When receiving data, this layer will get the signal received and convert it into 0s and 1s and send them to the Data Link layer, which will put the frame back together.

The functions of the physical layer are :

1. Bit synchronization: The physical layer provides the synchronization of the bits by providing a clock. This clock controls both sender and receiver thus providing synchronization at bit level.
2. Bit rate control: The Physical layer also defines the transmission rate i.e. the number of bits sent per second.
3. Physical topologies: Physical layer specifies the way in which the different, devices/nodes are arranged in a network i.e. bus, star or mesh topolgy.
4. Transmission mode: Physical layer also defines the way in which the data flows between the two connected devices. The various transmission modes possible are: Simplex, half-duplex and full-duplex.

* Hub, Repeater, Modem, Cables are Physical Layer devices.
** Network Layer, Data Link Layer and Physical Layer are also known as Lower Layers or Hardware Layers.

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Windows 10 - Installation

There are two approaches you can take for installing Windows 10 in your computer: Upgrade or a Clean Install.

Typically, when you upgrade your operating system, all your documents and applications remain unchanged, whereas with a clean install you would be starting again from scratch. But one important thing to verify first is if your computer has the necessary hardware to support Windows 10.

System Requirements

Although most computers nowadays probably have the necessary requirements for Windows 10. It will certainly be useful to know them in case you want to upgrade from an older system.

The main requirements are −

• A processor (CPU) with a clock rate of at least 1GHz.
• At least 1 to 2GB of memory (RAM), but Microsoft recommends 4GB.
• At least 16GB space in your hard disk.

One important thing to note is that the installation process itself will verify your computer hardware and let you know if it qualifies for a Windows 10 upgrade or not. If not, then you will need to upgrade your hardware.

Upgrade

If your computer qualifies for a Windows 10 upgrade, then you can follow these steps to perform the upgrade −