Setting up DASDID Controls

You do not need DASDID statements for DASD that provide their own physical IDs (for example, 3375s and 3380s). If you choose to code control statements for these devices, make sure the physical IDs you create match those switched into the storage directors.

Use the following steps to set up DASDID controls for your DASD subsystem.

STEP	ACTION
1	Set up a diagram of your DASD configuration ( see Figure 1).
	a	Show all connections between DASD controllers, storage control units, and channels.
	b	Include all processors that can record data on the ERDS. See CPU 033333 in Figure 1.
	c	Label each channel or channel path.
	d	Label the devices that have physical IDs.
	e	Create physical IDs for the devices that do not provide their own:
		1)	Assign a unique ID to each 3880. Do not duplicate IDs used on other storage control units.
		2)	Assign a unique ID to each controller that does not have one. Do not duplicate IDs used on other controllers.
		3)	Determine the lowest unit address (or device number; the last two digits of the device address) for each string, by processor (CPU).
	f	Assign a unique label to each processor in the diagram.
2	Create a comment line (as shown in Figure 2) for each storage control unit, indicating the connected controllers and the DASD strings connected to them. For example: `*SCU15 CTRL14,33,22 CPU A (980-995) B (800-815)` describes one of the storage control units shown in Figure 1. This is storage control unit 15, that is connected to strings 980–987, 988–98D, and 990–995 from CPU A (X11111); and to strings 800–807, 808–80D, and 810–815 from CPU B (022222). The paths to the devices are through controllers 14, 33, and 22, in that order.
	a	The comment lines serve two purposes:
		1)	They outline the DASDID statements.
		2)	They document the DASDID statements in case of future configuration changes.
	b	The STR value in the DASDID statement consists of the controller ID and the lowest address or device number from the string attached through that controller to the CPU.
3	Create DASDID statements according to the comment lines. Figure 2 shows the completed comments and DASDID statements for the configuration shown in Figure 1.

Figure 1shows one way to define the DASD configuration in an installation.

Important: This is an example; not a model configuration.

Figure 1. DASD Configuration Diagram for DASDID Statements. DASD Configuration Diagram for DASDID Statements

Figure 2 contains examples of the comment lines you create for each storage control unit, showing the controllers and the DASD strings connected to them.

Figure 2. Examples of DASDID Control Statements

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*******************************************************************
SYSEXN,TABSIZE=512K,HIST,DATE=84348,ACC=N
ENDPARM
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* CPU DEFINITIONS  A=X11111 B=022222 and 033333
* SCU 14     CTRL 02    A(778-77F)
DASDID CPU=X11111,CHP=07,SCU=14,STR=02778
* SCU 15     CTRL 14,33,22    A(980-995)  B(800-815)
DASDID CPU=X11111,CHP=09,SCU=15,STR=14980,STR=33988,STR=22990
DASDID CPU=022222,CH=08,SCU=15,STR=1400,STR=3308,STR=2210
DASDID CPU=033333,CH=08,SCU=15,STR=1400,STR=3308,STR=2210
* SCU EE     CTRL 14,33,22    A(A80-A95)  B(A00-A15)
DASDID CPU=X11111,CHP=0A,SCU=EE,STR=14A80,STR=33A88,STR=22A90
DASDID CPU=022222,CH=0A,SCU=EE,STR=1400,STR=3308,STR=2210
DASDID CPU=033333,CH=0A,SCU=EE,STR=1400,STR=3308,STR=2210
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