238 IBM eServer zSeries 900 Technical Guide
z/VM and VM/ESA migration path
Figure 7-3 shows two typical migration paths to the z900 - z/VM - 64-bit real (z/architecture
mode).
Figure 7-3 One-step-at-a-time migration path examples for VM
The difference between the two paths is whether to start the H/W upgrade or S/W upgrade
first.
򐂰 Path #1: a -> b -> c, is the preferred path if the current VM operating system level supports
the z900 server.
򐂰 Path #2: d-> e -> c, is the preferred path if the current VM level operating system level
does not support the z900 server.
You can assign both Central Storage (CS) and Expanded Storage (ES) on z/VM 64-bit
addressing mode so that guest operating systems can use ES.
7.8.2 Considerations after concurrent upgrades
Using CUoD, CIU or CBU, you can concurrently upgrade your z900 from one model to
another, either temporarily or permanently. We need to consider the effect on the software
running on a z900 when performing a CUoD, CIU, or CBU upgrade on a z900 processor.
Enabling and using the additional processor capacity should be transparent to all
applications. There is, however, a small class of applications that obtains the processor
model-related information, for example, software monitors and those applications that use the
processor model information as a means of verifying the processor's capacity.
There are two instructions used to obtain the processor model information:
򐂰 STIDP: Store CPU ID instruction
STIDP instruction provides a 1-byte hexadecimal version code, which is
x'00' on any
z900 server. The STIDP instruction also provides information on the processor type
(2064), serial number, and model.
z/VM
z/VM
(32-bit)
Software level upgrade
Hardware upgrade to z900
Architecture level u pg rade to 64-bit
d
a
Current
VM
Current
Processor
e
Current
Processor
z/VM
z/VM
64-bit
64-bit
z/VM
z/VM
(32-bit)
b c
Current
VM
z900
z900
z900
z900
z900
z900

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