IBM Personal System/2 50 - Page 38

Bit
4
This
bit
is
reserved
and
should
be
0.
Bits3-0
These
bits
are
undefined
for
a
write
operation
and
should
be
set
to
0.
Reading
these
bits
returns
the
arbitration
level
of
the
arbiter
controlling
the
channel
during
the
most
recent
grant
state.
This
information
allows
the
system
microprocessor
to
determine
the
arbitration
level
of
the
device
that
caused
a
bus
time-out.
3-6
Model
50
System
Board
—
October
1990