## Physical Device Driver Reference

[prev][next][parent][TOC]

### Capabilities Bit Strip

Level 3 device drivers have an additional DWORD field appended to the device header. Each bit of this new field is a flag indicating whether or not a particular feature is supported. The flags in this field are:

Bit 0 Set to 1, if DosDevIOCtl2 request packets are supported, and if shutdown support is provided.

Bit 1 For block device drivers, this bit is reserved and must be set to 0. Block device drivers indicate their ability to support greater than 16MB by way of the Query Device Parameters IOCtl (Category 08h, Function 63h) Device attributes field, bit 2.

For character device drivers, this bit is set to 1 (if memory addressing above 16MB is supported, that is, support for full 32-bit memory addressability verses 24-bit memory addressability).

Bit 2 Set to 1, if the physical device driver supports parallel ports.

Bit 3 Indicates that the physical device driver is participating in the adapter device driver strategy, which, in turn, selects an alternate INIT request packet format from the kernel.

Bit 4 If set to 1, the Initialization Complete Command (1Fh) is supported.

Bits 5-31 Reserved. Must be set to 0.