In this chapter, middleware has been defined as system software that acts as an intermediary between the application software and the kernel or device driver software, or as software that mediates and operates various application software. Application software has been defined as software that relies on system software and essentially gives the device its character and distinguishes it from other embedded devices, and application software is usually software that interacts directly with a user of the device. There are many functional and non-functional factors that need to be considered before making the decision, such as development time, interoperability, performance, etc. A number of middleware systems have been created using different combinations of standard services; The Internet Protocol is often used. CORBA has also been used as a model for distributed embedded services. Currently, there is no formal consensus in the embedded systems industry on how embedded systems middleware should be defined. So until there is a consensus, this book takes a pragmatic approach to defining what middleware is and how to categorize different types of middleware. Simply put, middleware is a layer of abstraction that acts as an intermediary. Middleware manages the interactions between application software and the underlying system software layers, such as. B the operating system and device driver layers. Middleware can also handle interactions between multiple applications that reside in the built-in device, as well as between applications that reside on networked devices. Oracle`s middleware solution is another very popular and powerful option for enterprise middleware.

In addition to communication between fundamentally different systems, middleware also performs several other functions. Middleware typically offers the following features: Embedded system designers have experimented with a variety of middleware architectures. Some systems generously use common standards: Internet Protocol (IP), CORBA, etc. Other systems define their own services and support. The extent to which standard services are used to create middleware versus custom services is an important design decision for embedded multiprocessors and distributed systems. Message-oriented middleware is one of the most widely used types of middleware. With message-oriented middleware, it becomes less complicated to use applications that are distributed across different platforms and run on different operating systems and network protocols. Networks-on-chips must provide quality of service capabilities to support multimedia and other speed-sensitive applications. Because NoCs typically don`t run the Internet Protocol, they often use their physical layer to effectively deploy QoS. This type of middleware is very handy when it comes to creating extended software systems to control robotic systems.

This type of middleware is most often used to perform synchronous data transfers that require the client and server to be online at the time of communication. With middleware, processes such as ordering and configuring products can be automated, improving lead times and costs compared to manually running these processes. Gill et al. [Gil03] used a planning framework that could combine and adapt different planning guidelines. Their Kokyu framework enables the combination of static priority planning, dynamic priority planning, and hybrid algorithms. Figure 6.20 shows how your planning system fits into the service stack. They measured the behavior of the system using three guidelines: monotonous rate planning, least laxity first, and a combination of RMS and least laxity first. They found that different policies have slightly different characteristics and that systems that can move from one planning policy to another can provide higher levels of service.

TOGETHER [Cad01] is a library for large data transfers that enables overlapping calculations and communications. The library is designed to be used with an annotated Java form that allows you to analyze array accesses and data dependencies to run individual programs and multiple data. The library provides send and receive features, including special versions for contiguous buffers. The emb_fence() function handles pending sending and receiving. Data transfers are managed by the DMA system so that programs can be run simultaneously with transmissions. Benini and De Micheli [Ben01b] developed a methodology for the energy management of network-on-chips. They advocate a stack of microgrids with three main layers: the physical layer; an architecture and control layer consisting of the OSI, network and transport data link layers; and a software layer consisting of systems and handle applications. At the data link layer, the right choice of error correction codes and retransmission schemes is essential.

The media access control algorithm also has a strong impact on energy consumption. At the transport layer, services can be connection-oriented or connection-free. Flow control also has a strong impact on energy consumption. A notification service provides a publish/subscribe system for event propagation. Gore et al. [Gor01] have developed a CORBA notification service that supports QoS services. Your system processes structured events that include a domain, event type and name, QoS characteristics for the event, and a record. The system specification describes several QoS properties. In general, IT industry analysts, such as Gartner and Forrester Research, classify middleware into two categories: middleware for enterprise application integration and platform middleware.

MPI (MultiProcessor Interface) is a specification for a middleware interface for multiprocessor communication. (MPICH is a well-known implementation of MPI.) It is designed to facilitate the development and porting of scientific computing applications to homogeneous processors. .