HP Vectra User Manual

DMA controller 2 contains channels 4 through 7. Channel 4 is
used to cascade controller 1 to the 80286 microprocessor, and is
unavailable. Channels 5, 6, and 7 support 16-bit data transfers
between 16-bit I/O adapters, and 16-bit memory.
These 16-bit
DMA channels can transfer data throughout the 16
Mbyte system address space in 128 Kbyte blocks (64 Kbyte
words). Each 128 Kbyte block is a page of memory. All DMA
memory transfers through channels 5-7 must occur on even-byte
boundaries.
Address Generation
Addresses for DMA channels are not incremented or decremented
through page boundaries. The following figure shows the 24-bit
system address is generated by the DMA controller and the DMA
page register together.
24 Processor Board

HP Vectra Specifications

General

Processor	Intel Pentium
RAM	Up to 128 MB
Storage	HDD (capacity varies by model)
Operating System	Windows 95
Graphics	Integrated
Ports	Serial, Parallel
Expansion Slots	ISA, PCI