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Blog posts of '2012' 'July'

What is EPIC?

EPIC is to define a new industry open standard for small form factor embedded computer boards, call Embedded Platform for Industrial Computing or EPIC. The EPIC single board computer has multiple I/O expansion options. Its size is midway between the industry standard PC/104 module and EBX board. The boards in EPIC form factor support advanced processors plus complex I/O functions for applications involving data acquisition, video processing, telecommunications, networking, motion control plus the associated field wiring termination, I/O circuit protection, etc. The initial specifications define PC/104 expansions; however, future updates will embrace PCI Express and/or other expansion features. The EPIC standard provides a platform on which to build the next generation feature-rich embedded system for industrial, medical, military, transportation, and commercial applications.

Key Features

  • Fixed Dimensions and mounting holes
  • Fixed I/O Interface
  • Fixed PCI-104, PC/104 location
  • Fixed CPU location
Windows 7 - Key Benefits for Industrial Users

Industry is traditionally slow to adopt any new Microsoft Operating System (OS). Many industrial Windows users will have no need of the many new features on offer and will be highly cautious at potential bugs or security flaws that could be lurking within. The majority of industrial products will have life expectancies of over 5 years and would have been developed around a specific Operating System. In short, it is rarely worth considering switching to a new Operating System unless you are developing a new product.

At first glance, the appearance of Windows 7 is similar to Windows Vista. However, when you start using it you will be pleasantly surprised at how fluid and quickly it runs. Interestingly, if you compare the minimum hardware requirements between Windows Vista and 7 they are almost identical. However, Windows 7 was developed from the ground up with a simple aim to be much faster than Windows Vista. This is a significant change of thinking from Microsoft, especially when considering the upgrades which were necessary when moving between Windows 98, XP and Vista. The minimum hard drive capacity for Windows 7 of 16GB is still significantly larger than Windows XP which was a mere 1.5GB. Those users wanting a trimmed down version can choose Windows Embedded Standard “Quebec”, which is based on Windows 7 code.

Multiple Core Support

Similar to Windows XP and Vista, Windows 7 follows suit with the number of supported processors. The Professional, Ultimate and Enterprise editions all support two physical processors regardless of the number of cores within each processor. However, unlike Windows Vista and XP Windows 7 supports up to 256 cores and scales in a linear fashion.

Windows 7 64-bit

Excluding Windows 7 Starter, each of the editions will ship with 32-bit and 64-bit variants. The 64-bit versions will also support 32-bit applications. Although 64-bit computing has some significant benefits, if the applications or hardware does not fully support this , you should stay with 32-bit to avoid unexpected errors.

Advantages and Disadvantages of 64-bit

  • The 32-bit compatibility mode has overheads and running 32-bit applications within a 64-bit environment may be slower!
  • Your older 16-bit applications will no longer run. DOS applications are a no-go as far as 64-bit is concerned.
  • It is possible to address more than 4GB of system memory. This can provide some significant speed improvements for demanding systems. If your application is only 32-bit it will only see 4GB.
  • You will need a compatible Windows 7 64-bit driver. If you are running older or specialized plug-in cards or peripherals, you will find they no longer work.

Windows 7 XP Mode

To make use of this feature, you need to download and install both Microsoft Windows Virtual PC and Windows XP Mode.

The technicalities surrounding XP mode are a little vague and first impressions could give false hope of providing a fully compatible Windows XP machine. The XP Mode is designed to support legacy software applications only and cannot see or interact with most hardware. If any hardware was plugged into the machine such as a PCI Data Acquisition card, the virtual XP Mode would be oblivious to it.

This feature may be of use if you have a standalone legacy application which you are unable to run within Windows 7 which would otherwise have to be run on a separate PC.

Solid State Disk (SSD) Support

Windows XP and Vista treat an SSD as a mechanical hard drive. To support the growing popularity of SSD being used within systems, Microsoft has added a number of features into Windows 7 to improve the life expectancy and performance of Solid State Disks.

  • Disk activity has been optimized to reduce the amount of disk writes and cache flushes. All SSDs have a limited number of write/erase cycles, so this reduction improves the life of the device as well as improving the speed of operation.
  • Disk defragmentation is disabled when a device is recognised as an SSD. As data is written and erased from a standard hard drive it becomes fragmented over time. Defragmentation relocates data sequentially on the drive, so the head does not have to travel as much. This feature is not only unnecessary on an SSD, but the additional reading and writing of the process will shorten its life.
  • Windows 7 disables Superfetch, ReadyBoost and boot / application launch prefetching. These features were added to Windows Vista to improve the performance of conventional hard drive I/O but they have proved to be of no benefit for newer SSDs which make no distinction between random and sequential operation.
  • Windows 7 will support the new ATA TRIM command. This feature gives the SSD the control to erase unused data blocks. This will reduce the number of block erase and merge operations to further extend the life of the SSD and improve performance.
  • Microsoft has announced a certification program for SSD, similar to the driver certification program.
PCI Express – What you really need to know!

PCI Express improves on PCI by using high speed multiple lanes. A single lane consists of a transmit and receive pair, which operate in full duplex at 500MB/s. The lanes can be grouped together in multiples to form links. For example a PCI Express x16 slot would have a single link made up of 16 lanes.

PCI Express connectors are available as x1, x4, x8 and x16 and offer the following bandwidths: -

LinksBandwidth
x1 500MB/s
x4  2GB/s
x8  4GB/s
x16  8GB/s

Slots are not always what they seem

The PCI Express standard is very flexible. A plug-in card can be fitted to any slot which is at least as large as it is. For example a x1 card will function in a x1, x4, x8 and x16 slot.

Slots don’t have to be electrically wired with the full compliment of lanes, as long as the electrical power and ground connections are tracked in. It is common for products to have x8 or x16 physical slots which are only x4 and x8 respectively. For this reason, it is always necessary to read the fine print of the product specification.

A PCI Express card will negotiate and use what lanes are available on the socket it is plugged into. However, the function of a card could be severely impaired if it is running on less lanes that it was designed to make use of. This is an important consideration when using high performance peripherals such as RAID and graphics cards.

Graphics and Server Architectures

All motherboards and Single Board Computers (SBCs) are based around specific chipsets. Typically the chipset is made up of two large scale devices named the North and South bridge. These devices interface with the processor and all of the subsystems on the board.

Graphics based chipsets are optimised for multimedia use where high performance video is required and nearly all have a x16 link optimised for graphics card use. Some high end gaming motherboards have two or more x16 slots that support Nvidia ‘SLI technology’. In addition to the dedicated graphics link, four lanes are available to be configured as the board manufacturer wishes. Typically these will be utilised as four x1 board slots. Non-graphics cards should not be used in a x16 graphics slot unless the card manufacturer specifically states compatibility.

Server chipsets are designed to service high throughput plug-in cards such as RAID and fibre channel controllers. They do not have dedicated graphics links, so more lanes are available to be configured as the board manufacturer wants. This more flexible approach means that boards such as the Intel server motherboard S5000xxx are available in a number of variants with different PCI Express connector options. However, the maximum link size is usually limited to x8.

Single Board Computers and PCI Express - PICMG

The international organisation which controls how Single Board Computers and backplanes are designed is called PICMG http://www.picmg.org/ . The latest version of the standard (PICMG 1.3) defines two separate classes of product which deal with graphics and server based architectures. The two standards are not interchangeable and it is possible to damage products if SBCs and backplanes from either class are mixed.

Most SBCs on the market are graphics class. This is due to the products being based on desktop processors and chipsets such as the Intel Core 2 Duo. Desktop chipsets also have more integrated features which make them a more cost effective option.

Server class SBCs are based on server chipsets and processors such as the Intel Xeon or an AMD Opteron processor.