Option ROM Mapping, PCI Interrupts, Link Layer

System Support

Link Layer

The link layer provides data integrity by adding a sequence information prefix and a CRC suffix to the packet created by the transaction layer. Flow-control methods ensure that a packet will only be transferred if the receiving device is ready to accomodate it. A corrupted packet will be automatically re-sent.

Physical Layer

The PCI Express bus uses a point-to-point, high-speed TX/RX serial lane topology. One or more full-duplex lanes transfer data serially, and the design allows for scalability depending on end-point capabilities. Each lane consists of two differential pairs of signal paths; one for transmit, one for receive (Figure 4-1).

System Board

Device A

PCI Express Card

Device B

Figure 4-1. PCI Express Bus Lane

Each byte is transferred using 8b/10b encoding. which embeds the clock signal with the data. Operating at a 2.5 Gigabit transfer rate, a single lane can provide a data flow of 200 MBps. The bandwidth is increased if additional lanes are available for use. During the initialization process, two PCI Express devices will negotiate for the number of lanes available and the speed the link can operate at. In a x1 (single lane) interface, all data bytes are transferred serially over the lane. In a multi-lane interface, data bytes are distributed across the lanes using a multiplex scheme.

4.2.3 Option ROM Mapping

During POST, the PCI bus is scanned for devices that contain their own specific firmware in ROM. Such option ROM data, if detected, is loaded into system memory's DOS compatibility area (refer to the system memory map shown in chapter 3).

4.2.4 PCI Interrupts

Eight interrupt signals (INTA- thru INTH-) are available for use by PCI devices. These signals may be generated by on-board PCI devices or by devices installed in the PCI slots. For more information on interrupts including PCI interrupt mapping refer to the “System Resources” section 4.3.

4.2.5 PCI Power Management Support

This system complies with the PCI Power Management Interface Specification (rev 1.0). The PCI Power Management Enable (PME-) signal is supported by the chipset and allows compliant PCI peripherals to initiate the power management routine.

4-4

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Technical Reference Guide

dc7900 specifications

The HP dc7900 is a well-regarded desktop solution that serves as a testament to HP's commitment to performance, reliability, and user accessibility. Introduced as part of HP’s Compaq line and designed primarily for business professionals, the dc7900 combines powerful processing capabilities with a compact form factor that suits various office environments.

One of the standout features of the HP dc7900 is its robust configuration options. It typically comes equipped with Intel's Core 2 Duo or Quad processors, giving users the ability to handle demanding applications seamlessly. The inclusion of Intel's technologies, such as Intel vPro, enhances remote management and IT control, making it an ideal choice for businesses looking to streamline their operations.

The dc7900 is designed with flexibility in mind. It offers multiple form factors, including mini-tower, small form factor, and ultra-slim desktop configurations. This variety enables organizations to choose a model that best fits their workspace requirements, maximizing both efficiency and aesthetics. The small footprint models are particularly beneficial in space-constrained environments, while the mini-tower version provides expandability for future upgrades.

In terms of graphics capabilities, the HP dc7900 typically features integrated Intel graphics, with options to install discrete graphics cards for users who require enhanced visual performance. This makes the dc7900 suitable for tasks ranging from standard office applications to more graphics-intensive responsibilities.

Connectivity is another key characteristic of the HP dc7900. It is equipped with a variety of ports, including USB 2.0 and audio jacks, allowing users to connect peripherals easily. Additionally, the dc7900 supports legacy connections, making it easier for businesses with older equipment to integrate new systems without hassle.

Durability and reliability are hallmarks of the HP dc7900. Built with high-quality materials and subjected to rigorous testing, this desktop is designed to withstand the demands of a bustling office environment. Furthermore, HP's comprehensive warranty and support options assure businesses of the reliability of their investment.

The HP dc7900 is not just a powerful desktop; it’s a versatile and dependable solution for modern businesses. With its combination of performance, expandability, and solid build quality, the dc7900 remains a relevant choice for those looking to enhance their productivity and efficiency in the workplace.

HP dc7900 manual Option ROM Mapping, PCI Interrupts, PCI Power Management Support, Link Layer

Models: dc7900