PCs and the Service Layer

Any PC that claims to be DMI 2.0-compliant must, as a minimum, have the Service Layer installed in addition to the CI and the MI. A machine preloaded with the service layers can be queried for a list of major components, such as the processor, BIOS and memory. As it turns out, most PC vendors have yet to implement all management functions within the DMI service layer, with the exception of remote LAN wake-up, which is available on almost all DMI 2.0-compliant PCs. Unfortunately many other useful functions generally are hardware-specific. For example, the Compaq Insight Manager's temperature monitor is a good management tool, but as you might guess, you can't use it with other vendors' hardware.

Regardless of how the management functionality is provided with the PC, or whether it is fully DMI 2.0-compliant, you will need remote-management software that you can install on a "console" machine to monitor the state of your network PCs. Intel's LANDesk Client Manager is by far the most common remote-management software. However, top computer manufacturers bundle their own software: Compaq provides Insight Manager, Dell provides OpenManage, Hewlett-Packard provides TopTools and Digital provides ClientWorks. IBM's solution is based on Intel's LANDesk Client Manager (LDCM) with added proprietary capabilities.

The most useful form of monitoring is Health Monitoring, which lets you track memory errors, disk errors, temperature rising, voltage and even chassis intrusions, among other things. Some of these features require you to install additional hardware on the monitored PC, such as a physical switch to recognize when a system cover is removed and alert you to chassis intrusion.

Another cool feature offered by all top computer vendors is PXE (Preboot Execution), which lets the PC perform some operations before it boots the OS. If you want to implement diskless boot, then you need a special BIOS that includes a PXE agent and another third-party software solution, such as Intel's LANDesk Configuration Manager. The combination lets you configure the machine to look for the OS on the network at book time. This feature, which has been around for a long time in Unix workstations, can be used very creatively by network administrators to manage their networked PCs.

Logistics

The relationship between the SP and the management applications can be one to many. Thus, multiple applications can talk to one SP. At the same time, the relationship between the SP and the component instrumentation can be one to many, too. Thus the overall relationship between the management applications, the SP and the component instrumentation can be many-to-one-to-many.

For purposes of identification, management applications must register with the DMI SP before they can participate in management functions. Component instrumentations must install into the DMI SP once when first introduced to the system. Components implemented using the Direct Interface MUST register with the DMI SP when they wish to notify it of their immediate availability. The mechanics of "connecting" to the DMI SP to register or issue commands may differ among operating systems and DMI SP implementations.

In a typical flow, a management application initiates control through the MI interface to instruct the SP to provide a service. However, as shown in figure 4, the specification allows for indications, which are unsolicited reports that flow from the component instrumentation to the SP and possibly to the management application(s).

The SP has two interfaces, the MI (Management Interface) and the CI (Component Interface).