50 S/390 PID: ThinkPad Enabled for S/390
A conceptual network is shown in Figure 5-1. In this example, a single instance of FLEX-ES
is executing (in system B in the center of the figure). It is using remote resources on the other
two systems; disk resources on system A and a tape drive on system C. The FLEX-ES
resource managers in all three systems communicate with each other. The emulated S/390
is unaware that some of the emulated devices are on remote systems.
System and device definitions are required on all three systems. These would include the
following lines:
System A:
adisk: cu 3990
interface network(1)
System B:
channel(3) network
channel(4) network
cu devad... path(3) resource(adisk)
cu devad... path(4) resource(atape)
System C:
atape: cu 3480
interface network(1)
Figure 5-1 FLEX-ES Networking
5.10 Disk caches
FLEX-ES automatically caches 15 tracks of data for each emulated 3390 or 3380. You can
adjust this in three ways:
򐂰 Specify a different number of tracks to cache for a particular emulated drive.
򐂰 Specify a different number of tracks to cache at the control unit level; excess tracks (above
those needed for the specified or default cache for each device on the control unit) will
float, as needed, among all the devices on the control unit.
Linux
OS/390
FLEX-ES
resource
manager
ckd
emulation
tape
emulation
ckd
emulation
resource
manager
UnixWare
Linux
resource
manager
S/390 volumes
S/390 volumes
LAN
LAN
LAN
A
B
C

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