Hardware resources

The execution delay of each vertex must be associated with a particular input sequence when there are vertices in the graph with data-dependent delay. The reason is because the time required to achieve synchronization and the number of iterations necessary for a data-dependent loop are known only in the context of a given input sequence. 

The latency of a constraint graph is the minimum numb of cycles that is required to execute all operations subject to timing constraints. The latency is computed hierarchically in a bottom-up manner according to the following definition. 

Definition 4.2.1 For a particular input sequence, the latency of a constraint graph is equal to the length of the longest weighted path from source to the sink, where  

The execution delay of a call vertex is exactly equal to the latency of the called graph. 

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The NIPALS algorithm is easy to program, particularly with a matrix-oriented computer notation, and is highly efficient when only a few latent vectors are required, such as for the construction of a two-dimensional biplot. It is also suitable for implementation in personal or portable computers with limited hardware resources. 

Share hardware resources such as printers and modems. 

Please note that layers and tiers are two different concepts. Tiers mean the physical separation of subsystems—each subsystem runs on a different hardware or the same hardware but in different processes. In a multitiered system, the interaction between the subsystems is accomplished through remote procedure calls (RPCs). Any RPC involves network overhead and therefore has a performance penalty whether the remote procedure is on a separate hardware or on the same physical hardware but in a different process. Layers, on the other hand, are logical separations of the subsystems. Each layer can run on a different physical tier, or all layers can run on a single tier. The purpose of physical tiers is to leverage distributed hardware resources or to reuse a piece of software that is deployed on a different hardware that your system wants to leverage. The purpose of layered software architecture is to separate the system into highly cohesive and loosely coupled modules (see Chapter 2 for software development principles). 

Web-based systems offer several advantages over rich client easy to deploy and access, easy to scale (by adding more hardware resources to the application server), and shared computing resources (CPUs, memory, database connections). However, most of the information this book presents is not limited to Web-based applications. It promotes the loosely coupled Presentation Layer and Domain Layer so that business logic can be reused no matter what GUI technology is being used. 

Until the late 80 s, the software development was very much curtailed by the limitations of hardware, where the size of the memory was the most critical factor. Today, about a decade later, the most critical aspect for large scale parallel MD simulation is not the hardware, but the software. Coping with increased problem and algorithmic complexity, as well as, varying hardware platforms is a daunting task. Adding the requirement of optimal use of hardware resources makes the development or modification of an efficient and portable parallel MD simulation software a formidable challenge. 

The next topic you learned about was the Basic Input Output System (BIOS). The BIOS is the software hard-coded into a chip on the motherboard and manages the relationships between the hardware resources of a computer and the operating system. In this section you learned about the different brands of BIOS software and the major differences between them. 

Another example of a hardware resource is a resource discovery expansion-card. These cards, when installed into any expansion slot, will tell you what resources are being used in the computer and will indicate any possible conflicts. Several companies make these cards. 

System self-checks and enumerates hardware resources. Each machine has a different startup routine, called the POST (power on self-test), which is executed by the commands written to the motherboard of the computer. Newer Plug-and-Play boards not only check memory and processors, they also poll the systems for other devices and peripherals. 

Virtual device drivers, the Windows kernel, and the GDI load. Once the system is in 32-bit mode, various 32-bit virtual device drivers load to manage hardware resources, often replacing 16-bit real-mode drivers. The Windows kernel, which controls access to the processor from Windows 9x, is loaded into memory, and once the graphical display interface (GDI) loads to manage screen I/O, the system is ready to accept customers. 

A. Utilities provide a way for a user to control the provisions and use of hardware resources and are a suhcategory of system software designed to enhance the operating system. 

The wizard will ask you a series of questions that will help you to configure the printer. The first question it will ask you is Do you print from MS-DOS-based programs The reasoning behind this question is similar to the reason we map drive letters. Most older DOS programs (and to a lesser extent, Windows programs) don t understand the UNO path syntax for access to a shared resource. Instead, they understand a name for a local hardware resource (like LPTl, for the first local parallel port). So, you must point a local printer port name out to the network in a process known as capturing. If you need to capture a printer port, answer Yes ... 

In addition to market evolution, hardware capabilities consistently double every year or two. A consequence is that, every 3 to 7 years, a system may require fundamental redesign in order to take advantage of the roughly lOx improvement in hardware resources that have become available. 

System software is intended to control the hardware resources of a computer system to provide useful functionality for the user. For example, an operating system tries to optimize the use of resources such as processor, memory, and input-output devices to enable users to run various programs efficiently. A database system tries to maximize the use of memory and disk resources to allow different users to access data concurrently. 

As opposed to application software, the requirements of system software are tied directly to the capabilities of the hardware platform. The requirements must deal with computer concepts such as hardware resources and interfaces. The software engineering of system software typically requires specialized knowledge such as transaction processing for databases or process scheduling for operating systems. 

Partitioning is a means for providing isolation between components to contain and/or isolate faults. Partitioning between components may be achieved within the system architecturally by allocating unique target hardware and hardware resources to each component. Alternatively, partitioning may be achieved within the component architecture to allow multiple software or hardware items to run within the same hardware platform. Partitioning should ensure ... 

First of all, work has been performed on the optimization of the control unit architecture. One particular architectural feature that has been investigated is the subroutine mechanism. Subroutines enable the reuse of hardware resources this could significantly reduce the area of the controller while also providing a shorter critical delay path. An algorithm has been developed that automatically... 

The partitioning is based on the mobility P op) of operations, which is limited through ASAP- and ALAP-scheduling. A probability p(op,t) can be associated with each operation, indicating the probability that operation op will finally be found in clock cycle t If an operation op has, for example, the mobility P op) = 3 then it is assumed that it will be finally scheduled with a probability of p op,t) = I into clock cycle t, ASAP op) < t < ALAP op). To estimate the distribution of all hardware resources, the probability of a single operation type can be summed up within a clock cycle to derive the so-called distribution graph D ... 

Multicore AMP systems can be extremely complex, especially in consolidated systems where multiple operating systems are used. This means that more effort needs to be expended on ensiuing that the system configuration and its implementation is correct, in particular the hardware resource partitioning which needs to be performed manually. 

Done by the InHAL module, using a force-directed scheduling algorifiim that tries to schedule the operations so as to balance the distribution of operations using the same hardware resources, without lengthening the schedide. First, both an ASAP schedule... 

Phase 2 — Preliminary schedule the InHAL module balances the distribution of operations that use the same hardware resources, using the default allocation. 

Hardware resources, e.g. function units, registers and connections, could be shared when they are executed alternatively. Hence, the exploiting mutual exclusiveness is important in order to reduce required hardware resources. 

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