It mainly depends on how often you update the memory in the Key. Each bit of the memory in a Rockey4 or Rockey4ND Key can be re-written at least 100,000 times. Additionally, Rockeys employ "Wear Leveling" which distributes the re-written bits to the "least worn" areas of the memory. Wear Leveling extends the life of the Rockey and also makes it more reliable throughout its lifetime.
All access from your protected program to the Rockey memory is done via KeyChk calls. To deter "eavesdropping" and "tampering", KeyChk uses a number of security protocols when "talking" to your Rockeys. These protocols require a higher number of "write-cycles" to the Rockey's EEPROM than simply accessing an unprotected memory. We have done extensive testing and found that Rockeys are able to handle between 5,000 and 10,000 KeyChk updates.
The following examples will show how to use the above information to predict the lifetime of your Rockeys. They assume a worst-case scenario of the Rockey being able to handle only 5,000 KeyChk updates.
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If you build a Rockey WITHOUT a Uses Limit or Time Limit and use KeyChk Function 1 to verify the Rockey's
presence and read it's data, then you can do this
as often as you like without impacting it's
lifetime. Even if you check every 60 seconds to see if the Rockey is
still plugged into the computer, it will NOT have a
negative effect on the lifetime of the Rockey. In this case, your Rockey should last
about 10 years. This is the expected lifetime of a Rockey whose memory is never updated.
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If you build a Rockey with a Uses Limit to
"meter" how many times your program is used, then you
will have to use KeyChk Function 2 to update the Uses Limit stored in the Rockey. Each time you do this, it will count as one of those
5,000 updates that the Rockey is able to handle.
So, if your program updates the Uses Limit twice per day, then the lifetime should be about 2,500 days (5,000 divided by 2). If your program is used 5 days per week, that means the Rockey should last about 9.6 years (5,000 divided by 2 updates per day, divided by 5 days per week, divided by 52 weeks per year).
If the same program is used twice per day, 7 days per week (instead of 5), then the lifetime of the Rockey drops to about 6.9 years (5,000 divided by 2 updates per day, divided by 7 days per week, divided by 52 weeks per year).
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If you build a Rockey with a Uses Limit to
"meter" program functions that are used throughout the day,
the lifetime of the Rockey could be much shorter than the above examples.
For this example, let's say that your program requires one Uses Count every time the User creates an Hourly report. This would mean that your program is using KeyChk Function 2 EIGHT time per day, 5 days per week. In this case, you would need to replace the Rockey in about 2.4 years (5,000 divided by 8 updates per day, divided by 5 days per week, divided by 52 weeks per year).
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If you build a Rockey with a Time Limit to "meter" how many Days your program is used, then you can use KeyChk Function 1 to verify the Rockey's presence, read it's data and ensure that it has not Expired due to the Time Limit. Each Day the Key is used will count as one or two of those 5,000 updates that the Rockey is able to handle. If the Rockey is used 5 days per week, your Key should last about 9.6 years (5,000 divided by 2 updates per day, divided by 5 days per week, divided by 52 weeks per year).