Hi,I don't see a question in your post. I'm guessing you want to know if it will work. The dallas chip will work fine, and gives you some extra non volatile memory. An automated system using rs232 port will cost a lot to implement, it just depends on how many customers you have.
A simple scheme (hardly hacker-proof): Customer provides serial number. Internal ID# is extracted from a list using serial number. XOR a multi-bit feature code with the internal ID# = your key
By not revealing the internal ID#, it's harder for someone to observe patterns in the keys, particularly a reseller who sees a lot of them. The step below would complicate enough that S/N and ID# could be the same value.
Some complicators: Make only some of the feature code bits valid (say, 4 bits, distributed across the key), and make the rest of the bits random before the XOR step when the key is genned. Again, thwarts obvious patterns. Simply AND in the device to filter them out after XOR.
Consider: The key needs to be long enough to thwart sequential keying attempts. With 8 digits, I can just code something that steps through all the combinations and activates all the features. Of course, you could have some land mine codes that lockout the device for factory reset. :-)
Any danger of getting stiffed on payment? If so, key immediately with an expiring key (time, uses) that gives enough time for funds to clear, when you re-issue a permanent key.
Embedded feature upgrades are a really interesting issue.
My company has found that (at least in our products) customers will rarely purchase software upgradeable features after the initial sale of the product. They will although purchase a higher end product incorporating a feature for fear of possibly needing the feature later, if no upgrade is possible. They also don't feel they should have to pay for a feature that is just a software difference, or just a change in code. But if that change is a special memory card with that software on it, it will be accepted (They need something tangible). In my industry it's interesting that the embedded market has not made the jump that the general software industry has working at for years.
Any others see this?
PeeJayBlack
Wouldn't surprise me. I remember a tape drive speed upgrade which consisted of changing pulleys and belts.
-- Al Balmer Balmer Consulting removebalmerconsultingthis@att.net
I'm reminded of a story from many years back... supposedly when IBM customers bought the 10MB to 20MB mainframe disk upgrade, the "installation" consisted of a technician removing the set-screw that kept the head from travelling the full range. I imagine there was a little more to it, but humerous nonetheless.
Very interesting!
We've considered keys for metered usage or site-specific licensing, but not for feature enablement. Instead, different versions of the product will be available from the factory (as the product evolves), with factory upgrades available (new firmware, faceplates, and labeling). Like a trade-in, but without the leftover "used" gear". We're planning to support field firmware upgrades, but only for bug-fixes.
Interesting logic to consider. I have a similar example.
We're developing a piece of network test equipment; something that would have as likely an audience amongst consultants (read: mobile) as corporations (fixed installation). Curiously, we found market perception to give greater value to a large rack-mount version than a lightweight handheld version - by a factor of 10+. We expected the opposite, but to a lesser extreme. It pays to do market research.
So, we'll be selling only a 1U rack-mount version in a steel case (maybe with some lead weights thrown in for "added value" :-). All for a 4x6" PCB. In the end, it's likely to be better for business anyway because instead of consultants bringing their own portable tools to the job, they are more likely to install units the customer purchases themselves. We hope. ;-)
Yes, or perhaps requiring a factory return for the upgrade (for higher-cost, lower-volume goods). It seems that removing the mystery around the product (by making it customer-servicable) diminishes some of the respect in many cases (and perhaps value perception).
I can see how this might occur. Perception is that I've bought the hardware, and now I should be able to use it to the fullest (i.e., the software is an "entitlement"). However, when buying software, the perception is more clearly one of buying functionality, so there might be less perceived entitlement to new unpaid features.
buys
Many thanks for all the responses, and for the insight into how users see firmware-enabled upgrades to equipment - very telling! I am guessing we will experience a similar reaction ;)
In pratice, we might make the user return the unit to their reseller so they can perform the upgrade - this might make the cost seem more acceptable to the customer(?)
Best regards,
Jim
Thanks for your advice, Lewin. Yes, in the past RS232 for us has been amazingly troublesome for such a simple interface, whether it be due to Windows version/laptop ports etc. We do have an up/down/enter kind of keypad on the unit and so I'll try to implement it via that. It turns out I will also need to implement an RS232 method, since we now intend to ship some types of unit without any keypad at all.
Jim
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