In a recent note, Ron and Jenny Hawkins said:
> Date: Sat, 1 Jul 2006 09:38:04 +0800
>
> I don't see it as counterintuitive at all. My recollection is that AVGBLK as
> value for SPACE was around well before the AVGREC parm became available.
>
> SPACE=(27998,(1000,100)) where 27998 is AVGBLK
>
> A requirement to specify space based on number of records of a given size
> was serviced by providing the AVGREC parameter, which acts as a switch to
> say that the first value SPACE Parm is AVGREC instead of AVGBLK, and to use
> the subparm as a multiplier for primary and secondary space requests.
>
> SPACE=(1024,(1000,100)),AVGREC=K where 1024 is AVGREC
>
> I've used this rather simple JCL technique for around 10 years. I have
> endured nothing because it such a damn easy thing to use.
>
> However, I do like the suggestion to use K and M shorthand for the Space
> subparms, but don't you think that a switch would still be required to have
> the first subparm interpreted as AVGBLK or AVGREC?
>
I'm still trying to grasp what records, or their size, means to
allocation. I thought records come into play only later, at access
method time. So, I tried an experiment:
//
//SIZES JOB 'Account','Paul Gilmartin',
// MSGLEVEL=(1,1),REGION=0M
//*
//* Test various suboptions of SPACE=
//*
//USERC OUTPUT JESDS=ALL,DEFAULT=YES,
// CLASS=R,PAGEDEF=V0648Z,CHARS=GT12
//*
//DOIT PROC
//*
//ALC EXEC PGM=IEFBR14
//SYSUT1 DD DISP=(MOD,CATLG),UNIT=SYSALLDA,
// SPACE=(10000,&NUM)&AVG,DSN=&SYSUID..AVGALC&SUF
//*
//GEN EXEC PGM=IEBGENER
//SYSPRINT DD SYSOUT=(,)
//SYSIN DD DUMMY
//SYSUT2 DD DISP=(MOD,CATLG),UNIT=SYSALLDA,
// SPACE=(10000,&NUM)&AVG,DSN=&SYSUID..AVGGEN&SUF
//SYSUT1 DD DISP=SHR,DSN=SYS1.MACLIB(GIMZPOOL)
//*
//DOIT PEND
//*
//NONE EXEC DOIT,NUM=1024,AVG=,SUF=N
//UNIT EXEC DOIT,NUM=1024,AVG=',AVGREC=U',SUF=U
//KIBI EXEC DOIT,NUM=1,AVG=',AVGREC=K',SUF=K
//*
//* :w ! submit
The results from ISPF DSLIST, without and with AVGREC=U:
Data Set Information
Data Set Name . . . : SPPG.AVGALCN
General Data Current Allocation
Volume serial . . . : TSO008 Allocated tracks . : 205
Device type . . . . : 3390 Allocated extents . : 1
Organization . . . : NONE
Record format . . . : ?
Record length . . . : 0
Block size . . . . : 0 Current Utilization
1st extent tracks . : 205 Used tracks . . . . : 0
Secondary blocks . : 0 Used extents . . . : 0
Data Set Information
Data Set Name . . . : SPPG.AVGALCU
General Data Current Allocation
Volume serial . . . : TSOCT1 Allocated tracks . : 209
Device type . . . . : 3390 Allocated extents . : 1
Organization . . . : NONE
Record format . . . : ?
Record length . . . : 0
Block size . . . . : 0 Current Utilization
1st extent tracks . : 209 Used tracks . . . . : 0
Secondary bytes . . : 0 Used extents . . . : 0
So, why do I get slightly more tracks with AVGREC=U than without?
Why is the first extent displayed in tracks when I specified a
unit of blocks or records respectively? Why is the (unused)
secondary displayed in blocks in one case, and bytes in the other?
And, when initialized by IEBGENER:
Data Set Information
Data Set Name . . . : SPPG.AVGGENN
General Data Current Allocation
Volume serial . . . : TSO032 Allocated blocks . : 410
Device type . . . . : 3390 Allocated extents . : 5
Organization . . . : PS
Record format . . . : FB
Record length . . . : 80
Block size . . . . : 27920 Current Utilization
1st extent blocks . : 70 Used blocks . . . . : 1
Secondary blocks . : 0 Used extents . . . : 1
Data Set Information
Data Set Name . . . : SPPG.AVGGENU
General Data Current Allocation
Volume serial . . . : TSO019 Allocated bytes . . : 11,670,560
Device type . . . . : 3390 Allocated extents . : 4
Organization . . . : PS
Record format . . . : FB
Record length . . . : 80
Block size . . . . : 27920 Current Utilization
1st extent bytes . : 3350400 Used bytes . . . . : 27,920
Secondary bytes . . : 0 Used extents . . . : 1
Why does it say I have 410 blocks when I asked for 1024?
Etc.
Are the formulae used published anywhere?
And, basically, this user would prefer to be able to specify:
SPACE=(BYTE,10G)
... and let the computer perform the computation.
-- gil
--
StorageTek
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