A product line includes most people who work full-time on a product, including that product's programmers and marketing people. Since there are quite a few projects at Autodesk that could conceivably become separate product lines, it makes sense to group them into product families. Each product family would have a General Manager (GM) and a General Management team. Each product within the product family would have a Product Management team, with the Product Manager (PM) reporting to the General Manager. The General Manager would report directly to the President of Autodesk.
In the simplest case, the General Manager would have the following responsibilities and authorities vis-à-vis product managers:
The General Manager negotiates with the Product Manager on the product's target profitability, taking into account the development needed to position the product and the family for long term success.
The General Manager may break a single product into multiple products, or merge multiple products into a single product, as he/she deems appropriate for strategic reasons.
In this simple case, the GM and the PM do not need daily contact, as most of the authority resides with the PM. In practice, this relationship will often be built on a product-by-product basis. For example, if a product is allowed to run at a loss, because the GM sees a strategic advantage to the product family, the GM and PM probably need to work out a relationship which very clearly guarantees that the GM's strategic purpose is being fulfilled.
Also, because in the simple case the GM does not have much work to do, GMs would frequently double as PM for one of the products in the family. As a rule, no one should act as PM for more than one product--the purpose of the product-line structure is to guarantee that the total success of each product gets the total dedication of at least one person, and having one person act as PM for multiple products defeats that purpose.
Editor: John Walker