The Care and Feeding of ISDN4BSD
5.4.1 The I/O Port	5.4 Kernel Configuration for	5.4.3 The Interrupt Number

5.4.2 The Memory Address

In addition to using space in the i/o address space, this card also uses 4 Kilobytes address space in the main memory address space. It may be configured in increments of 0x2000 within the space of 0xc0000 to 0xde000. Usually, VGA cards occupy space from 0xc0000 to 0xc7fff, so you have to use something from 0xc8000 upward. 0xd0000 or 0xd8000 are sometimes free, so lets assume for now no other card in your machine occupies the 4Kb space from 0xd0000 and we use this value to configure our card.