## MMPM/2 Device Driver Reference

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### Boot Sequence

To initialize the device before the other device drivers load, the MAD16. ADD device driver has to load before the other device drivers (Audio/CD-ROM ). OS/2 loads device drivers in a specific order. Device drivers needed to boot the system are loaded early. Less critical device drivers including audio are loaded toward the end of the device driver load sequence. In a particular class of device drivers, load order is based on order in the CONFIG.sys.

Device driver load order is as follows:

1.Kernel known basedevs (resource manager)
2.BASEDEVs
a..ADDs first
b..SYS
3.Non-BASEDEVs (for example, Audio)

To load early, the MAD16.ADD wakeup code is written as a BASEDEV .ADD. This insures that regardless of CONFIG.SYS order, it loads early. For CD-ROM however, both the wakeup code and CD-ROM device driver are .ADDs. This creates an install requirement that the MAD16.ADD precede the CD-ROM device driver in CONFIG.SYS.