As of Jan 1st 1999, Novell’s policy is to only certify new systems if they are
compliant with the NWPA driver architecture (that is, SCSI controller drivers with
the ".ham" file extension, and tape and ASPI drivers with the ".cdm" file
extension).

The NWPA driver architecture can be used with NetWare 3.12 / 4.11, (providing
the appropriate patches have been loaded - see

http://support.novell.com/misc/patlst.htm

) and with NetWare 3.2 / 4.2 and 5.x.

The NWPA driver architecture replaces the DDFS monolithic ".dsk" driver
architecture used with NetWare 3.x and NetWare 4.x. The DDFS driver
architecture is not supported by NetWare 5.x.

rationale

Novell introduced NWPA with NetWare 4.x, as an alternative to the DDFS driver
architecture (which originated as a way of controlling disk drives - hence the driver
extension ".dsk"). It enabled NetWare to easily and dynamically support a wide
range of peripheral devices - something not so easily achieved with the
"monolithic" DDFS architecture.

the layered driver approach

NWPA has been designed from the ground-up to dynamically support many
different devices. It uses a layered driver structure, as used in many other
operating systems. This allows different abstractions of devices to be used at
various layers in the driver stack.

For example, for SCSI tape drives, at the lowest level would be (one or more)
SCSI Host Bus Adapter (HBA) driver(s). These drivers have the extension ".ham"
(standing for host adapter module). On top of these would be layered (one or
more) Tape Drive driver(s). These drivers have the extension ".cdm" (standing for
custom device module - in this case, a tape class driver).

tape class drivers

Tape Class drivers are mainly used by Novell’s own backup applications -
SBackup for NetWare 3.x / 4.x) and SBCON for NetWare 5.x. As with the DDFS
architecture, Independent Software Vendor (ISV) backup applications tend to use
the ASPI (Advanced SCSI Programming Interface) layer to communicate with
tape drives. Therefore, when using backup applications such as BackupExec and
ArcServeIT, the relevant ASPI layer driver must be loaded in place of the normal
tape driver. See the answer to the question

"How do I know what drivers (DDFS or

NWPA) I am using at the moment, and what drivers I need for running tape
backups?"

for further details.

Further services can be layered on top of the class driver modules, such as
NetWare 5’s Storage Management Services. This is used by NetWare 5’s built-in
backup application "SBCON", and by many other backup applications, to provide
media management abstraction. (Refer to the

"SBCON Quick Reference Guide"

for full details of Novell's SBCON backup application.)

NWPA minimum recommended patch level

The main component of NWPA is the NetWare Loadable Module "NWPA.NLM". If
your system has this module loaded, then it should support NWPA. For NetWare
versions up to 3.12, additional patches will be required before you can upgrade to
run NWPA. If you are using NetWare 3.x and 4.x you are advised to upgrade your
system to the patch level recommended by Novell’s "Minimum Patch List" at

http://support.novell.com/misc/patlst.htm.

The minimum recommended NWPA patch level for NW3.1x, 3.2 and 4.1x is
NWPA_UP.EXE, which can be found at the following location:

http://developer.novell.com/devres/sas/certinfo.htm.

For NW3.12 the NWPA_UP.EXE patch should be uncompressed in the
SERVER.312 directory. This also contains patch 312PTD.exe, which should be
uncompressed and applied following the instructions given in the accompanying
312PTD.txt file.

For NW3.2 all that needs to be done is to uncompress NWPA_UP.EXE in the
SERVER.312 directory

Note : NetWare 4.1x Support Pack 7, 4.2 and 5.x do not require this patch.

dynamic loading / unloading of drivers

NWPA supports dynamic loading/unloading of drivers, and will auto-load certain
drivers if it recognises supported devices. For example, once an HBA ".ham"
driver is loaded, if an operational tape drive is found on the SCSI bus that is
supported by the SCSI2TP.CDM (NetWare 3 / NetWare 4) or NWTAPE.CDM
(NetWare 4.2 and 5) tape device drivers, NWPA should auto-load the tape device
driver.

next question

Go to the next question

"How do I know what drivers (DDFS or NWPA) I am using

at the moment, and what drivers I need for running tape backups?"

file:///C|/Documents%20and%20Settings/topher.COL-SPRINGS/Desktop/dltvs80%20manual/document/common/drivers_faqs/eng/nw_q1.htm [11/29/2001 8:35:19 AM]

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