Experimental Physics and
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If it ain't broke - don't fix it. Most of the time, it's not so simple. It is reasonable to assume that most of these devices are always broken, at least a little bit. It's a matter of deciding whether the fix (new firmware, new software, etc) is worth the effort and risk (introducing new bugs or exposing latent bugs) of the upgrade. Some vendors are better about giving you the information to make this decision then others. We are in the process of upgrading firmware on our AB PLCs. We have identified a few cases where a bug which bit us has been fixed in later firmware, but in other cases it is unclear from the release notes whether the fix is really what we need. There has been one case where the upgrade introduced a new problem (undocumented decreased stack size) but luckily that showed itself immediately and the change could be backed-out. But overall, the upgraded firmware seems to be an improvement, and having consistent levels of firmware used everywhere helps in understanding what we have. Josh Stein wrote: > With the proliferation of small highly-distributed IOCs and > remote I/O we are seeing a rapid increase in the number of > "intelligent" devices connected to our control systems. . . . > Often times this firmware is not quite... as firm... as one > would hope Just one of the hidden costs of highly distributed remote I/O. As Bob said, hardware is cheap compared to labor. More protocols and device drivers to support, more types of spares to keep track of, more types of devices to troubleshoot, more network nodes, more network traffic, etc. Josh Stein wrote: > Finally; assuming firmware updates are an accepted price to pay > for COTS devices, how do we manage and track them? The work is in deciding which devices are worth tracking and then for those, knowing which firmware version is installed where, which firmware version you want installed, and knowing when the vendor releases a new version which may be better then what you have. We are concentrating on devices which have a more direct impact on availability (such as PLC processors and communication modules) and dealing with other devices on a case by case basis. Overall, not that different then dealing with software, but potentially a lot more devices and often more difficult in getting detailed information on the changes.
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ANJ, 02 Sep 2010 |
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