Specifying binary highkeys

A binary key that is always even is one example of a binary key that can use HIDAM HIGHKEYs. Because a key is never odd, it never ends in hex ‘FF’. Increasing a binary key in increments of more than one between keys, leaving a “gap” that allows you to define a HIGHKEY that is not used by the application is another, more common example.

This shows, the HIDAM keys are binary integers that are increased in increments of 100 each time a key is inserted.

Full Word Integer Keys in Increments of 100 (X’64)

Key (in Decimal)	Hexadecimal Value
100	X'00000064'
200	X'000000C8'
300	X'0000012C'
400	X'00000190'
500	X'000001F4'

In this example you can choose a HIGHKEY that is not used by the application, as any fullword integer divided by a decimal 100 never ends in hex ‘FF’. In this example, you can use a HIGHKEY of x'00001FF'.

You must know your application when defining hexadecimal HIGHKEYs for binary keys. If the increment is unpredictable and it can be an odd number, you will find it difficult to choose a HIGHKEY.