Technical data

Device Support on OpenVMS Systems
7.10 Required Change in ISA_CONFIG.DAT on AlphaStation 200/400
The following table shows the changes to the device description block.
Table 7–2 Changes to Device Description Block
Before Version 7.1 After Version 7.1
[AUA0] [AUA0]
NAME=AU NAME=AU
NODE=3 DRIVE=SYS$MSBDRIVER
DRIVER=SYS$MSBDRIVER IRQ=9
IRQ=9 DMA=(0,1)
DMA=(0,1) PORT=(388:4,530:8)
PORT=(388:4.530:8) NODE=3
Customers using SYS$MANAGER:ISA_CONFIG.DAT files should read
Section 7.9.
7.11 Memory Holes on AlphaServer 4100 Systems
V7.1
Physical memory holes may exist on AlphaServer 4100 systems. As illustrated
in Figure 7–1, there are three different sizes of memory daughter card pairs:
512 MB, 256 MB, and 128 MB. In accordance with AlphaServer 4100 systems
configuration rules, memory card pairs must be arranged in descending order of
size.
The AlphaServer 4100 hardware reads the first set of memory daughter cards
and assumes that any memory card pairs that follow are the same size. Memory
holes occur because memory card pairs following the first set of cards read by
the hardware may not be the same size. As shown in Figure 7–1, the hole at
3000.0000 must be dealt with by OpenVMS. The hole at 4800.0000 is at the top
of the address space and can be ignored by OpenVMS.
Note
Previous versions of OpenVMS Alpha did not efficiently support systems
with physical memory holes and ultimately led to an inefficient use of
system memory. The memory management data structures in OpenVMS
Alpha Version 7.1 and later have been slightly modified to recognize
the memory holes. As a result, inefficiencies in previous versions of the
OpenVMS Alpha operating system have been eliminated.
Device Support on OpenVMS Systems 7–7