• Contract Name: vow.sol
• Type/Category: DSS —> System Stabilizer Module
• Associated MCD System Diagram: https://github.com/makerdao/dss/wiki
• Contract Source: https://github.com/makerdao/dss/blob/master/src/vow.sol

1. Introduction (Summary)

The Vow contract represents the Dai Credit System's balance sheet. In particular, the Vow acts as the recipient of both the system surplus and system debt. Its main functions are to cover deficits via debt (Flop) auctions and discharge surpluses via surplus (Flap) auctions.

Pictured:

• Inter-contract calls necessary for the module function

Not pictured:

• cage calls from Vow to Flap and Flop
• Auction and user auction interactions
• Governance calls / interactions

2. Contract Details

Vow (Glossary)

• sin: the system debt queue.
• Sin: the total amount of debt in the queue.
• Ash: the total amount of on-auction debt.
• wait: length of the debt queue
• sump: debt auction bid size, i.e. the fixed debt quantity to be covered by any one debt auction