H

HAL

The hardware abstraction layer. Consists of hardware and device driver mechanisms that insulate applications from device-specific implementation details. If a capability requested by an application is not implemented by the current hardware, the capability is emulated by the software.

hardware blitter

A hardware component, built into the display adapter, that performs efficient blit operations.

HEL

The hardware emulation layer. Provides software-based emulation of features that are not present in hardware.

HID

Human Interface Device. A USB class representing devices that allow a human to control a computer.

hit detection

See collision detection.

host

In DirectPlay, a virtual player whose ID is DPID_SYSMSG. The host manages system messages and messages sent to all players in a session.

HREF

Horizontal refresh. In a video stream, the HREF is active to signal that the display is to begin a new scan line. See also VREF.