DASD utilization tables

Table 1 shows two things:

The storage capacity of various types of devices presented as MBTYPES/VOLUME, BTYES/TRACK, and TRACKS/VOLUME.
How JES2 assigns SPOOL devices based on each device's characteristics and where the SPOOLDEF initialization statement parameters have been set with TGSIZE=30 and BUFSIZE=3992. The values in the table represent what JES2 uses in calculating the available SPOOL Device storage.
For example:
1. JES2 uses BUFFERS per TRACK of 10 for either 3380s or 9340s and uses a BUFFERS per TRACK GROUP of 30.
2. JES2 uses BUFFERS per TRACK of 12 for 3390s and sets the BUFFERS per TRACK GROUP to 36.
3. For a mixture of devices (3380s, 9340s, and 3390s), JES2 starts with TGSIZE=30 and makes the appropriate adjustments for each device types (that is, 3380s and 9340s get 30 BUFFERS/TRACK GROUP and 3390s get 36 BUFFERS/TRACK GROUP).

When you have identified the device types for use as SPOOL devices and have set your SPOOLDEF initialization statements, you use this table to identify how JES2 utilizes these devices and how JES2 allows for their storage limitations.

Table 1. Calculated values for several DASDs
Device attribute	Spool device type characteristics
Device attribute	3380	3380E	3380K	3390-1	3390-2	3390-3	9340-1	9340-2
MBYTES/VOLUME	630	1260	1890	946	1892	2838	1003	1502
BYTES/TRACK	47476	47476	47476	56664	56664	56664	46456	46456
TRACKS/VOLUME	13275	26550	39825	16695	33390	50085	21600	32340
Note: Characteristics of 3390 Model 2. For 3390 Model 1 capacities, divide the volume characteristics by 2.

Table 2. Calculated values for several DASDs - BUFSIZE and TGSIZE
Device attribute values (BUFSIZE=3992, TGSIZE=30)	Spool device type characteristics
Device attribute values (BUFSIZE=3992, TGSIZE=30)	3380	3380E	3380K	3390-1	3390-2	3390-3	9340-1	9340-2
BUFFERS/TRACK	10	10	10	12	12	12	10	10
TRKCELL	4,5	4,5	4,5	3,4,6	3,4,6	3,4,6	4,5	4,5
TRACKS /TRACK GROUP	3	3	3	3	3	3	3	3
BUFFERS /TRACK GROUP	30	30	30	36	36	36	30	30
KBYTES /TRACK GROUP	120	120	120	144	144	144	120	120
TRACK GROUPS /VOLUME	4425	8850	13275	5565	11130	16695	7200	10780
Usable MBYTES/VOLUME	530	1060	1590	800	1600	2400	862	1291
Device Utilization(%)	84	84	84	85	85	85	85.9	85.9
Note: Characteristics of 3390 Model 2. For 3390 Model 1 capacities, divide the volume characteristics by 2.

Table 3 provides device utilization percentages for selected DASD based on several JES2 initialization parameter BUFSIZE specifications.

The 3390-9 is supported for SPOOL. See Specifying the storage of checkpoints on DASD for information on using the SPACE= parameter.

Table 3. Selected device and BUFSIZE parameter (on SPOOLDEF) values and resultant utilization percentages
UTILIZATION (%)
DASD	BYTES /TRACK*	BUFSIZE	BUFFERS /TRACK	DEVICE**	STORAGE***
3380	47476	3992	10	84	97
		3856	11	89	94
		1944	19	78	95
3390	56664	3992	12	85	97
		3856	12	82	94
		3768	13	86	92
		1944	22	76	95
9340	46456	3992	10	85.9	97
		3672	11	89.6	65
		1944	18	75.3	95
* Values presented as “Maximum Block Size Per Track” in MVS/DFP Managing non-VSAM Data Sets Device Utilization % = BUFSIZE x buffers/track bytes/track * Storage Utilization % = BUFSIZE x buffers/page bytes/page (= 4096)