NonStop S-Series Server Description Manual (G06.24+)
Introduction
HP NonStop S-Series Server Description Manual—520331-003
1-14
Maximum Processor Enclosure I/O
Maximum Processor Enclosure I/O
A single processor enclosure can support 16 disk drives using the two SCSI buses, 
and in addition provides two differential SCSI ports, two Ethernet ports, and any I/O 
devices connected to two ServerNet adapters. Figure 1-8 shows this maximum 
configuration for one processor enclosure.
There is a slight difference in the way this I/O capability is managed in different server 
models. In the case of the NonStop S7600, S74000, S76000, and S86000 servers, an 
additional router port is available and is used to provide a separate ServerNet bus 
interface (SBI) for the disk drives on the SCSI buses. In the case of NonStop S7000, 
S7400, S70000, and S72000 servers, the disk drives are managed through the same 
SBI as the Ethernet ports and differential SCSI ports, as shown in Figure 1-7.
ServerNet adapters always have a ServerNet bus interface (SBI) for connecting to the 
ServerNet routers and one or two ServerNet addressable controllers (SACs). The SAC 
is specialized to the type of input/output service provided, such as ATM 
communications. As shown in Figure 1-3 on page 1-7, ServerNet adapters are installed 
in slots 51 through 54.
Note that one unused router port is available in each of the MFIOBs. This port is 
reserved for expanding the ServerNet fabric. See Expansion to Second Processor 
Enclosure on page 1-16.
Figure 1-7. Alternate Configuration of MFIOBs for NonStop S7000, S7400, 
S70000, and S72000 Servers
Multifunction
I/O Board
Multifunction
I/O Board
ServerNet Bus
Interface (SBI)
ServerNet Bus
Interface (SBI)
Differential
SCSI Port
Differential
SCSI Port
X Y
SCSI
SAC
SCSI
SAC
SCSI
SAC
SCSI
SAC
SCSI
SAC
SCSI
SAC
Ethernet
Port
Ethernet
Port
Ethernet
SAC
Ethernet
SAC
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