The application layer is a layer in the Open Systems Interconnection (OSI) seven-layer model and in the TCP/IP protocol suite. It consists of protocols that focus on process-to-process communication across an IP network and provides a firm communication interface and end-user services.
The application layer is the seventh layer of the OSI model and the only one that directly interacts with the end user.
The application layer provides many services, including:
- Simple Mail Transfer Protocol
- File transfer
- Web surfing
- Web chat
- Email clients
- Network data sharing
- Virtual terminals
- Various file and data operations
The application layer provides full end-user access to a variety of shared network services for efficient OSI model data flow. This layer has many responsibilities, including error handling and recovery, data flow over a network and full network flow. It is also used to develop network-based applications.
More than 15 protocols are used in the application layer, including File Transfer Protocol, Telnet, Trivial File Transfer Protocol and Simple Network Management Protocol.
System software layer:
Middleware has two separate but related meanings. One is software that enables two separate programs to interact with each other. Another is a software layer inside a single application that allows different aspects of the program to work together.
The most common type of middleware is software that enables two separate programs to communicate and share data. An example is software on a Web server that enables the HTTP server to interact with scripting engines like PHP or ASP when processing webpage data. Middleware also enables the Web server to access data from a database when loading content for a webpage. In each of these instances, the middleware runs quietly in the background, but serves as an important “glue” between the server applications.
Middleware also helps different applications communicate over a computer network. It enables different protocols to work together by translating the information that is passed from one system to another. This type of middleware may be installed as a “Services-Oriented Architecture” (SOA) component on each system on the network. When data is sent between these systems, it is first processed by the middleware component, then output in a standard format that each system can understand.
Firmware is a software program or set of instructions programmed on a hardware device. It provides the necessary instructions for how the device communicates with the other computer hardware. But how can software be programmed onto hardware? Good question. Firmware is typically stored in the flash ROM of a hardware device. While ROM is “read-only memory,” flash ROM can be erased and rewritten because it is actually a type of flash memory.
Firmware can be thought of as “semi-permanent” since it remains the same unless it is updated by a firmware updater. You may need to update the firmware of certain devices, such as hard drives and video cards in order for them to work with a new operating system. CD and DVD drive manufacturers often make firmware updates available that allow the drives to read faster media. Sometimes manufacturers release firmware updates that simply make their devices work more efficiently.
You can usually find firmware updates by going to the “Support” or “Downloads” area of a manufacturer’s website. Keeping your firmware up-to-date is often not necessary, but it is still a good idea. Just make sure that once you start a firmware updater, you let the update finish, because most devices will not function if their firmware is not recognized.