Installation guide

command at the console firmware prompt:
>>> show version
3.5.3 Restrictions and Known Problems
The following restrictions apply to Compaq Alpha VME 4/nnn and 5/nnn
SBCs.
3.5.3.1 Byte Addressability Not Supported by mmap (5/nnn Only)
In addition to sparse and dense addressing modes, the Compaq Alpha VME
5/nnn SBC hardware supports byte addressability. This includes the ability
to perform simple math on a byte address to derive and access other byte
addresses.
Currently, byte addressability is not supported by the Tru64 UNIX mmap
interface.
VMEbus device drivers running on Compaq Alpha VME 5/nnn SBCs can
continue to use the same sparse and dense space macros as in previous Tru64
UNIX releases and in existing VMEbus device drivers. Note that using the
macros to access memory can help maintain the driver’s binary compatibility
(portability) across VMEbus platforms.
Byte addressability for Compaq Alpha VME 5/nnn SBCs will be supported
in a future release of Tru64 UNIX.
3.5.3.2 VME Autovectors
The Compaq Alpha VME 4/nnn and 5/nnn SBCs do not support VME
autovectors.
3.5.3.3 Network Port Termination
A Compaq Alpha VME 4/nnn or 5/nnn SBC that has the network configured
in an UP state must have its external network connection properly terminated.
If the network connection is unplugged or not properly terminated, then the
network software will periodically time out and perform a network reset.
This is normal for an unterminated Compaq Alpha VME system. However,
it will cause high system latencies during the reset period, resulting in delays
of about 10 milliseconds that can affect the realtime performance of the
system.
Note that a loopback connector is not sufficient to terminate the network
connection.
Processor-Specific Notes 3–7