Theory of Operation 4-17
♦16 bit addressing (full programmable)
♦10 selectable IRQs
♦4 selectable DMA Channels
♦3 SIRQ Inputs allows external devices to mapping IRQs
♦100-pin TQFP package - PC87338VJG
4.2.8 Hard Disk Drive Subsystem
The Hard Disk Drive Subsystem, implemented on the Main Board Board and on the
associated hard disk drive module(s), provides disk storage for all system software and
user files.
The notebook is equipped with a high-capacity hard disk drive. The hard disk drive also
features built-in power conservation features configured from the standard CMOS
Setup Routine. An Automatic Power Down mode can be selected which powers down
the drive motor during periods of inactivity. An additional level of power conservation
may also be selected which powers down the motor plus all control circuits.
The hard disk drives are factory formatted as a single drive (Drive C:) and are preloaded
with installation versions of Windows 95 or Windows for Workgroups (in dual load
versions, the user selects operating system during software installation).
The Hard Disk Controller is implemented with the PCIO643 Controller Chip described
in greater detail in the following paragraph.
4.2.8.1 PCI0643 Features
♦Capable of 16 MB/second transfer rates in DMA mode - up to 20 MB/second
in PIO mode
♦Supports bus master DMA at 133 MB/second PCI burst rate
♦Support PCI DMA transfers for both DMA-capable and PIO-only drives
♦Fully supports ATAPI DMA/PIO transfers
♦2 channels - supports up to 4 IDE drives
♦Surpasses and supports Enhanced IDE Mode 3, Mode 4 and propose Mode 5
timing from the widest range of disk drive manufacturers
♦Supports multi-word and single-word DMA modes 0, 1 and 2
♦Fully supports the latest PCI-IDE specification and all the Plug-and-Play (PnP)
specifications.
♦Supports Windows 95, Windows NT 3.1 and 3.5 (Daytona), and OS/2™