The server-on-module era begins

PICMG has published the COM Express Release 3.0 specification. It not only features an upgrade for the latest existing pin-outs for Type 6 and Type 10 modules, but most notable is the final release of the COM Express Type 7 specification.

It is the first module specification for server technologies, offering innovation that defines a new class of embedded computer technology: server-on-modules. What makes this new module class unique, what are the target markets and which processors fit?

The new COM Express Type 7 modules are similar in many ways to earlier generation modules; however, this is by design and essential to enabling new server-level capabilities. Form factor, connector location, number of signal pins, mounting holes, PCB board layers, heat spreader design, design-guide for carrier board layouts and embedded API guidance from PICMG all remain consistent. Even the pin-out has been changed only 23% compared to COM Express Type 6. But it is exactly these relatively small differences that transform a typical computer-on-module into a true server-on-module.

What makes the difference?

Support for 10 GbE and a rich set of PCIe lanes are the major characteristics of server performance. A server also needs to provide highest bandwidth possible to connect many standard computers via 1 GbE or thousands of smaller IoT devices. And COM Express Type 7 delivers: compared to Type 6, several interfaces have been removed to make room for up to four new 10 GbE interfaces and up to eight more PCIe lanes. All audio and video interfaces have been replaced, as well as four of the eight USB 2.0 ports, the ExpressCard interface and two of four SATA ports. This frees up 60 pins on the AB connector and 42 pins on the CD connector to accommodate the new interfaces. Performance is elevated from embedded computer-on-modules to server-on-modules, optimised for all types of carrier-grade edge and cloud computing as well as the broad spectrum of Industrial Internet of Things (IIoT) and Industry 4.0 applications.

Why do we need server-on-modules?

Modules provide an application-ready computing core so that developers no longer need to design and configure servers from the ground up. They need only to choose the suitable module, integrate an application-specific carrier board and define the required extensions and external interface. As a result, server-on-modules significantly reduce design efforts and resources as compared to the requirements of a full custom design. Test and certification demands are reduced as well, because the core is already tested and prevalidated for all major, globally recognised certifications.

Standardisation offers further benefits; for example, engineers can rely on identical interfaces for new or next-generation products. Designers are well supported by a range of vendors, improving long-term availability and ensuring freedom to choose the best solution. The broad ecosystem of accessories includes application-ready cooling solutions and carrier boards, enabling a competitive landscape for purchasing components or even re-using third-party layouts to minimise NRE costs. The form factor is used by a large community, which in turn ensures continuous improvement of the standard. As a vendor-independent standardisation body, PICMG has launched this new server-on-module standard and actively supports the developer community in promoting its value contrasted to proprietary solutions.

The first COM Express Type 7 server-on-modules from congatec with two 10 Gigabit Ethernet channels are equipped with headless computing power from 16-core Intel Xeon D1577 processor to the Intel Pentium D1519 processor for industrial temperature ranges from -40 to +85°C.

Which different server categories do server-on-modules target?

In most networked computing infrastructures, including both standard IT/carrier-grade data centres and network computing infrastructure, decentralised server nodes are the most in-demand applications and made possible through network functions such as virtualisation and software-defined networking (NFV/SDN). At the network edge, server-on-modules may play an important content distribution role; for example, in cloudlets (aka follow-me clouds or mobile micro-clouds). They are located at the edge of the internet and reside in the middle of a three-tier hierarchy that runs across mobile device to cloudlet to cloud. Their function is to decrease latency for response-critical applications and relies on the ability to support a very wide range of user-level computations; for example, voice recognition applications such as Siri, Alexa, Cortana and/or video transcoding with variable adaptive rates. Such systems need to also handle mechanisms for authentication, access control and metering, and must offer dynamic resource allocation for user-level computations.

In these performance-driven areas, modular designs offer better scalability and upgrade capacity at lower costs than conventional server designs; this results from system updates that can be executed across different processor, socket and memory generations. Only the module itself has to be changed instead of the entire board or system. This adds critical value in highly competitive markets, fuelled by users’ continued demands for greater performance at lower costs.

Decentralisation of server performance is also a growing embedded computing trend in IoT applications. Edge and fog server architectures, either private or publicly located, demand a highly individualised set-up in terms of interfaces connecting the field to local intelligence; this can range from wireless sensor networks to Industry 4.0 connected machinery. Examples can be found in smart cities, where decentralised server intelligence provides local processing and storage for real-time analytics in traffic management, emergency response or video surveillance for public safety. Smart grids and renewable energy parks also demand local intelligence with low latency, ideal to control power generation and distribution in real time. IIoT and Industry 4.0 applications also call for local server performance, consolidating real-time control of several machines, IoT connectivity and data analytics on a single industrial edge server. Even commercial data centre applications can benefit from server-on-modules.

COM Express Type 7 target markets:

• Carrier-grade computing at the edge of the grid
• Embedded IoT applications at the edge of a public grid
• Embedded IoT applications in a private grid
• IT-driven data centre applications
• IP-based base stations
• Public edge server
• Private edge server
• Server systems
• Cloudlets
• Public FOG server
• Private FOG server
• Cloud systems

Which processors come with server-on-modules?

The first server-on-modules made available are equipped with the Intel Xeon D processor family (codename: Broadwell DE). They offer headless computing power from a 16-core Intel Xeon D1577 processor to the Intel Pentium D1519 processor for industrial temperature ranges (-40 to +85°C). They offer up to 48 GB of 2400 MHz DDR4 RAM with or without error correction code (ECC). Engineers will be able to incorporate silicon from other vendors; for instance, look at the latest AMD launches. It can be expected that upcoming embedded variants of the Zen microarchitecture might be a good fit as well. So engineers will have access to a very attractive modular solution, which is instantly scalable as new server processors become available.

Heat pipe-based cooling solutions from congatec are designed for COM Express Type 7 server-on-modules.

What is the feature set of server-on-modules in detail?

The new conga-B7XD COM Express Type 7 server-on-modules from congatec come in a headless design and are available with 10 different server processors, ranging from the 16 Core Intel Xeon processor D1577 to the Intel Pentium processor D1519 for the industrial temperature range of -40 to +85°C. An outstanding characteristic of the congatec server-on-modules product family is the high level of network performance due to 2x 10 Gigabit Ethernet ports. They also support the NC-SI Network Controller Sideband Interface for connecting a baseboard management controller (BMC) allowing out-of-band remote manageability. Powerful system extensions, including server-class NVMe storage or GPGPU computing capabilities, can be connected via up to 24 PCIe Gen 3.0 Lanes and 8x PCIe Gen 2.0 Lanes. 2x SATA 6G ports are available for conventional storage media. Further I/O interfaces, including 4x USB 3.0, 4x USB 2.0, LPC, SPI, I²C Bus and 2x UART are featured.

For a quick start with COM Express Type 7 modules, congatec offers an evaluation carrier board, which routes all the defined signals to standard interface connectors. For Ethernet, it offers 10 Gigabit Ethernet SFP+ cages.

What else counts?

With application-specific, hardware-related software support, including standardised IoT APIs from the server-on-module manufacturer, developers can quickly create reliable custom cloudlet, edge and fog server applications. With congatec’s optional Embedded Design & Manufacturing Services, even complete custom server designs can be implemented quickly.

A white paper on the COM Express Type 7 specification is available for download from congatec.

*Christian Eder is Director Marketing at congatec and the COM Express 3.0 specification editor. He is a member of PICMG, also working as specification editor in the COM Express Workgroups for COM Express 2.0, COM Express 2.1, COM Express Design Guide 2.0, Embedded EEPROM and Embedded EAPI.