To turn complicated leave rules into a system, I first listed every condition the platform would need to know. Then an unexpectedly simple image appeared: a deck of cards.

How could an AS/400 manage leave that was too complicated for a manager’s notebook? I began by separating the requirements.

  • The type of leave
  • How each right is created
  • When each right may be used
  • When each right expires
  • What the employee may see
  • How balances are calculated for any date
  • What managers and HR may see
  • How HR may make authorized adjustments
  • A complete history of every update

Once the conditions were visible, the implementation no longer felt mysterious. I did not need the computer to imitate a paper form. I needed it to hold individual units of entitlement.

In other words, I needed to teach the AS/400 to play cards.

Not an actual game, of course. The card was a model: one tangible, countable object representing one unit of leave.

WRITTEN BYYoshio Taki

A systems engineer who loves IBM i / AS/400

CHAPTER 03 · PART 02 · EPISODE 1 / 9 STORIES · 35 STORIES TOTAL

Chapter 3 index · All 35 stories