– DASD controllers, such as the IBM 3990 and 3880's.
– Line printers, such as the IBM 3900
– Tape drives such as the IBM 3480, and 3490
– Communication controllers, such as the IBM 3745 unit
– SNA display controllers such as the 3174
–ESCONdirector
S/390 DASD Attachment
Direct channel connection of the IBM S/390 Integrated Server to S/390 ESCON
DASD devices is supported.The S/390 Serial Channel Adapter must be used
for this function.
Restrictions when using the S/390 ESCON Channel Adapter
– Only specific IBM devices have been tested.Because of timing
considerations, non-IBM implementations of these devices may not
function.
– DASD attachment is only supported on ESCON Serial Channel adapters.
– A maximum of two ESCON adapters is supported.
– Only ESCON channel functions are supported. ESCON to Parallel
converter and CTC function is not supported, however a S/390 Serial
Channel adapter can connect to another S/390 system where the CTC
“load” is in that system's channel.
– Multi-path is not supported (two channels to same device controller).
DASD/DiskStorage
S/370, S/390 DASD migration to internal disk storage
In some cases, migration of existing S/370 or S/390 DASD to the S/390
Integrated Server's internal emulated DASD is favorable.Standard
Dump/Restore programs should be used to accomplish this.
If the source DASD is ESCON attached to the IBM S/390 Integrated Server
then a program such as DFDSS can be used to copy the data from the
ESCON attached DASD to the emulated DASD on the IBM S/390 Integrated
Server without the intermediate step of dumping the DASD volume to tape.
If the source DASD has a prallel attachment to another S/370 or S/390 system,
then the DASD must be first dumped to tape, then restored to the emulated
DASD on the IBM S/390 Integrated Server using standard dump/restore
programs.
DASDCapacities
The IBM S/390 Integrated Server has sixteen internal Hot/Swap drive bays,
each of which can accommodate an 18GB disk drive.The normal configuration
will include up to sixteen 18GB disk drives providing approximately 255GB of
useable disk capacity in a RAID 5 configuration.To provide enough read/write
access mechanisms to maintain good performance, at least five active drives
are recommended to be configured for each IBM S/390 Integrated Server.
Using less than five active drives may seriously limit the disk I/O performance
of the system.
Additionally, you may be able to split your workload across multiple IBM S/390
Integrated Servers.Analysis is needed to determine if workloads and data can
be logically divided between an existing system and the IBM S/390 Integrated
Chapter 7.Planning Guide23