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

TX

RX

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.

 

Technical Reference Guide

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HP dc5850 manual Option ROM Mapping, PCI Interrupts, PCI Power Management Support, Link Layer, Physical Layer
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dc5850 specifications

The HP dc5850 is a desktop computer that was designed for business environments, offering a blend of performance, reliability, and efficiency. Released during the height of the mid-2000s, this system is powered by AMD processors, particularly the Athlon or Phenom series, which ensures that it can handle various computational tasks with ease.

The dc5850 features a compact chassis that adheres to the Microtower form factor. This design not only saves space but also allows for easier upgrades and maintenance. The unit typically supports a range of RAM configurations, with options for up to 8GB of DDR2 memory. This flexibility enables the user to tailor the system's performance according to their needs, whether for basic office tasks or more demanding applications.

Storage options on the HP dc5850 include a 3.5-inch HDD that can accommodate substantial data, with capacities typically ranging from 160GB to 1TB. The inclusion of a SATA interface ensures fast data transfer rates, which is essential for improving overall system performance. Moreover, the dc5850 boasts multiple USB ports, including USB 2.0 and sometimes even USB 3.0, facilitating easy connectivity with peripherals such as printers, scanners, and external drives.

Graphics capabilities on the dc5850 are generally provided by integrated solutions, although users have the option to add discrete graphics cards for enhanced performance in visual tasks. The system often comes with integrated audio, which supports basic multimedia needs without requiring additional sound cards.

In terms of connectivity, the HP dc5850 features built-in Ethernet for wired networking and may also offer options for Wi-Fi capabilities via PCI expansion slots. This makes it suitable for networked business environments, enabling seamless integration into office infrastructures.

The system is designed with energy efficiency in mind, complying with various environmental standards, thereby reducing its carbon footprint. This aspect may also lead to lower operational costs for businesses focused on sustainability.

Overall, the HP dc5850 stands out as a versatile desktop solution, catering to the essential needs of small to medium-sized businesses. With its combination of performance, expandability, and energy efficiency, it remains a noteworthy choice for users seeking reliable computing power in a compact and manageable form.
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