System Memory Size
There are two types of system memory, S/390 memory and the I/O and Service
Processor (IOSP) memory.
1. The P/390 has 256MB of ECC memory for use by the S/390 operating system
and S/390 applications. This should be sufficient for any VM/ESA, VSE/ESA,
and most OS/390 systems.Memory-intensive systems should consider using
I/O and Service Processor (IOSP) memory (also referred to as PC memory) to
emulate S/390 Expanded Storage (described below).
2. The P/390 code includes the emulation of S/390 Expanded Storage by using
the I/O and Service Processor (IOSP) memory.The I/O and Service Processor
(IOSP) memory consists of 128MB. This 128MB is standard and is the only
supported configuration.
Note: Ensure that OS/2 always has sufficient memory for itself.For
systems
with small cache or expanded storage sizes (less than 16MB), 48MB for
OS/2 should be sufficient.
S/370 or S/390 Tape Drives
Compatibility
If you exchange S/390 tapes with other S/370 and/or S/390, you need to
ensure the tape media that you choose is usable by those machines.Standard
IBM 3420, 3480, or 3490 tape drives can be channel attached via the S/390
Parallel Channel adapter or S/390 ESCON adapter.There is also a 3490E
tape drive that may be SCSI-attached using a differential SCSI adapter.
Tape size and compression
Figure 4 shows tape sizes with and without compression.
Restrictions
– The P/390 I/O subsystem does not support the READ BACKWARDS CCW
unless the SKIP bit is on.This may affect certain tape utility programs.It
applies to all tapes, whether emulated or SCSI-attached.
– The only supported SCSI-attached 3490 tape drive is the IBM 3490-F01.
(The use of the Adaptec AHA2944UW differential SCSI controller is
required for these drives.)
– The 4mm DAT tape drive is only provided for loading software and service.
It is not recommended to be used for backup procedures.
Figure 4. TapeSizewithandwithoutCompression
Tape Size Without
Compression
Size With
Compression
3420 120MB N/A
3422 120MB N/A
3480 200MB 400MB
3490E N/A 2.3GB
Chapter 7.Planning Guide25

Host Mainframe Access
ICA
Using ICA emulation, the IBM S/390 Integrated Server can be VTAM
peer-connected to a host system using SDLC to share host applications.An
ISA Wide Area Connector (WAC) is required in the IBM S/390 Integrated
Server and up to six ICA lines are supported.
XCA
Using XCA emulation, communication lines appear to VTAM as Lan adapters.
Current versions of VTAM on VM/ESA, VSE/ESA, and OS/390 ESA support
XCA. A Multiport Model 2 or ISA Wide Area Connector (WAC) is required in the
IBM S/390 Integrated Server and up to sixteen XCA lines are supported.
LAN3172/LCS3172
Using a local and remote LAN attachment with LAN3172 emulation, the IBM
S/390 Integrated Server can be VTAM peer-to-peer connected to a host system
(37x5, 3172, 3174 or ICA) to share host applications.Using a bridge or router
between the local and remote LANs allows the systems to appear to be
LAN-attached.
Using a local or remote LAN attachment with LCS3172 emulation, the IBM
S/390 Integrated Server can be TCP/IP peer-to-peer connected to a host
system (37x5, ICA, 3172) to share host applications.The TCP/IP connection is
for OS/390, VM/ESA, and VSE/ESA.
ESCON Serial Channel adapter
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.
CommunicationControllers
To get communication function there are several alternatives:
Channel-attached S/390 communication controllers (2703, 3720, 3745) using a
S/390 Parallel Channel adapter or S/390 Serial Channel adapter
Emulated XCA devices by using an ISA WAC or Multiport Model 2 adapter for
SDLC
Emulated XCA device by using a boundary node converter for SDLC and BSC
for speeds up to 56 Kbps
Emulated ICA devices using a wide area connector (ISA WAC) for SDLC or
BSC line interface using RS232, V.35, or X.21
The number of lines possible for each device, whether emulated or channel
attached differ and depends on how the device is configured.If you need greater
than six lines, please contact your Business Partner for configuration assistance.
26 S/390  Integrated Server