IBM s/390 manual Resource definitions, Emulated control unit types

defines two channels, with the channel numbers 3 and 1. The channel numbers must be unique, but need not be in sequence. The local keyword means the channels are emulated block multiplexor channels and are emulated using resources on the ThinkPad.1 The channel numbers (or path numbers) are somewhat arbitrary and do not necessarily mirror the channels you might have on a “real” S/390. The channel numbers you assign are not reflected in the device addresses (“device numbers”) used by OS/390.

The cu statement defines an emulated control unit. The devad parameter defines the beginning address and the number of (emulated) devices connected to the control unit. This address (or device number) is the address seen by the operating system. For example, if you want to “IPL from A82,” then address A82 would appear in a devad parameter.2 The path parameter specifies an emulated channel connected to the control unit. The resource parameter specifies the name of a section in a resource definition (described below) that defines the emulated devices connected to the control unit. Resource names, used in cu statements, must be unique.

The cu definition specifies a numberofunits for each cu. You must define this number of devices in the matching resource definition. For example:

cu devad(0xA80,12) path(2) resource(R10A3990)

specifies that 12 devices are attached to this control unit. The R10A3990 clause in the resources definition must contain 12 devices.

An end statement is required for the system definition, and the parameter should specify the same name as the system statement.

Resource definitions

Resource definitions refer to actual devices or files and are defined separately from system definitions. In practice, both a system definition and the corresponding resource definition might be in the same text file. Both must be “compiled” by the FLEX-ES cfcomp program, to produce syscf and rescf files, before they can be used.

Emulated control unit types

FLEX-ES emulates many control unit types (cutype parameters) and device types; the full documentation should be consulted for a complete list. The commonly used cutypes include:

3990		DASD control unit	(for all 3380 and		3390 devices)
3480	and 3490	Tape control unit	(for FakeTape and		SCSI tape drives)
3174		Terminal control unit		(for emulated	locally-attached 3270s)
3172		LAN control unit (for		Ethernet LANs)
3172TR		LAN control unit (for		token ring LANs)
3215		Typewriter system	console (mostly for VM and Linux for S/390)
2821		Unit record control unit (for emulated card reader/punch, printer)
ctc		Channel-to-channel control unit

1Other types of channels may be specified, such as byte multiplexor and channels using remote (via TCP/IP) resources. These are described in detail in the FSI documentation.

2For this example, we might have devad(0xA80,8) as the parameter. This defines 8 addresses, A80, A81, A82, and so forth. A82 is named in this sequence.

Appendix B. FLEX-ES parameters 75