HPFS under OS/2 2.0 supports the following:
- Command chaining by calling the volume manager with a list of all
contiguous sector requests required to fulfill an I/O request.
This function is supported for all types of direct access storage
devices (DASD).
- Scatter and gather by passing physical pointers to each page in
the data buffer (physically not contiguous) as part of the I/O
request. This enables I/O controllers that support the
scatter-and-gather capability, such as the IBM
small-computer-system-interface (SCSI) adapters, to perform
input/output in a single operation.
- Disk caching in the installable-file-system (IFS) driver, rather
than in the device driver
- Recognition of devices that have outboard caches (nonsystem
memory), incorporating them into the total caching scheme