2019.2

and cannot be re-used. Then, when someone writes on the document and sends the pen data
to PlanetPress Workflow (through a docking station or through Bluetooth), if the required
conditions have been met, the document will be "closed", its pattern released and available to
be used immediately.
An open document can also be called a "live" document, in the sense that it is only active
between the time where it is printed and the time where ink from the Anoto Digital Pen is
processed and the document is closed. This duration is called "time to live" or "TTL", and it is
the second very important number: how long is the pattern actually needed.
The third important number is based on your actual output needs. In other words, how many
documents do you intend to print on a regular basis that will contain a pattern?
These three numbers, together, represent an easy way to determine if the 20,000 patterns are
actually enough for you. Basically, if you generate X documents within a specific time frame but
N of these documents are closed through regular process (writing on them with a pen and
docking it) during that period, does the difference between both ever reach 20,000?
Example
Say you print 19,000 pages containing a pattern, every day. You may think you'll "run out of
patterns" after a single day. But if 18,900 of these documents are being written to and
processed within the day, at the end of the day you only have a 100 page difference, possibly
due to mistakes, lost pages, or errors during processing. In this specific example, you would run
out of patterns only after 10 days, assuming the numbers remained completely static. Since
there are easy ways to deal with these remainders (a simple automated process that, once a
day, closes any document that is older than 48 hours, for example), a correct implementation
like this one would be perfectly functional and not be affected by the 20,000 page limit.
Remember however that this means that 19,000 physical sheets of paper are printed every day,
and those 19,000 documents are written on using one or more Anoto Digital Pens, which are
then processed back into the system.
The example above actually uses numbers that are much higher than our typical PlanetPress
Capture user. That is to say, a vast majority of our users will never have to worry about reaching
the pattern limitation, unless their implementation is missing important parts, such as the
"cleanup" process. But this also means a smaller minority of our users may require more than
20,000 patterns, so let's deal with this now.
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