nobuf/max_attempts is a SAP Parameter attribute which is used to control Maximum number of attempts to get the number range buffer semaphore information. This is available within R/3 SAP systems depending on the version and release level.
Below is the standard documentation available and a few details of the attributes values .
This parameter specifies the maximum number of attempts to lock the
number range buffer. A work process waits 100 milliseconds between each
attempt. With a default value of 1200 attempts, this results in a
maximum waiting time of 120 seconds. If the number range could not be
locked in this time, it returns the error TIMEOUT.
See SAP Parameter Documentation for full SAP documentation for this profile parameter.