H

HAL

Hardware abstraction layer

An NT executive component that provides platform-specific support for the NT Kernel, I/O Manager, kernel-mode debuggers, and lowest-level device drivers. The HAL exports routines that abstract platform-specific hardware details about caches, I/O buses, interrupts, etc., and provides an interface between the platform’s hardware and the system software. For example, the HAL implements a routine to map each device driver’s bus-relative device interrupt vector to a system-assigned vector with a corresponding platform-specific hardware priority (DIRQL), as well as several routines that provide DMA support.

hardware exception

See SEH.

hardware priority

See IDT and IRQL.

HBA

Host bus adapter

A hardware device that “connects” NT and a SCSI bus. A SCSI miniport driver manages the lower layers of the SCSI-II protocol on the HBA. See miniport driver; see also port driver, class driver, SFD, and SCSI.

heap

See pool memory.

hyperspace

A block of virtual memory somewhere in kernel space, dedicated to the use of the NT Memory Manager. Every instance of a user-mode virtual address space has an associated hyperspace area where the Memory Manager maintains internal data (such as page table pages and WSLs) for the current process. See also kernel space and user space.