Posted: Fri May 04, 2007 3:08 am Post subject: how to convert cylinders to megabytes ??
I like to know, how to convert cylinders to megabytes
and Track to Megabyte conversion?
Code:
XXSORTOUT DD DSN=DEAA11A.SWARS(+1),
XX DISP=(NEW,CATLG,CATLG),
XX SPACE=(CYL,(2500,500),RLSE),VOL=(,,,10),
XX UNIT=SYSDA,
XX MGMTCLAS=MC0030,
XX DCB=(PSDSCB,DSORG=PS,RECFM=VB,LRECL=2004)
Joined: 01 Mar 2007 Posts: 475 Topics: 9 Location: Welsh Wales
Posted: Fri May 04, 2007 3:19 am Post subject:
Quote:
I like to know, how to convert cylinders to megabytes
and Track to Megabyte conversion?
I think I see the logic behind your request, but, the DASD allocation routines will convert whatever space allocation you have specified, records, Kb, Mb into either cylinder or track allocations. Personally I never bother.
Quote:
Here, I have coded RLSE parameter for DEAA11A.SWARS but still it shows 100% used.
How CYL,(2500,500) is shown as Tracks Used: 60000 Cyls: 4000
If you think about it, it would show 100% used. You have specified via RLSE that any unused space is released, so if all of the allocated space is being used it would be 100%. _________________ If it's true that we are here to help others,
then what exactly are the others here for ?
Joined: 01 Feb 2007 Posts: 1075 Topics: 7 Location: At Home
Posted: Fri May 04, 2007 3:21 am Post subject:
If you use RLSE all unused space ie released therefore what is left allocated is 100% used - no wasted space. you need the 3390 ref card or similar to find out how many records of that LRECL fit on a track and work from there. _________________ Utility and Program control cards are NOT, repeat NOT, JCL.
Joined: 01 Mar 2007 Posts: 475 Topics: 9 Location: Welsh Wales
Posted: Fri May 04, 2007 3:40 am Post subject:
Interesting JCL code too ..............
Code:
XXSORTOUT DD DSN=DEAA11A.SWARS(+1),
XX DISP=(NEW,CATLG,CATLG),
XX SPACE=(CYL,(2500,500),RLSE),VOL=(,,,10),
XX UNIT=SYSDA,
XX MGMTCLAS=MC0030,
XX DCB=(PSDSCB,DSORG=PS,RECFM=VB,LRECL=2004)
If you storage group have set up SMS properly, there is no longer a need to code JCL in the prehistoric manner.
I would have coded ...
Code:
XXSORTOUT DD DSN=DEAA11A.SWARS(+1),
XX DISP=(NEW,CATLG,CATLG),
XX SPACE=(CYL,(2500,500),RLSE),VOL=(,,,10),
XX RECFM=VB,LRECL=2004
If SMS assigns a DATACLAS to EVERY dataset, be it SMS managed or not, DASD or tape, then there is no need to code a model or pattern DSCB. What are the attributes of this model, if they are equally as archaic then maybe the BLKSIZE would be LRECL+4 which would waste a lot of DASD space.
RECFM and LRECL are parameters in their own right and no longer need to be coded as sub parameters of the DCB field. _________________ If it's true that we are here to help others,
then what exactly are the others here for ?
Joined: 01 Mar 2007 Posts: 475 Topics: 9 Location: Welsh Wales
Posted: Fri May 04, 2007 4:56 am Post subject:
If you look at what I would have coded you can see that I did not include DCB=
As I said, IF your SMS environment is set up correctly then you do not need the model DSCB in your JCL.
The model or pattern DSCB that you have specified may have an inefficient blocksize coded, and because you had coded DCB=(PSDSCB the blocksize used for your dataset would be the same as that of PSDSCB. _________________ If it's true that we are here to help others,
then what exactly are the others here for ?
Joined: 01 Feb 2007 Posts: 1075 Topics: 7 Location: At Home
Posted: Fri May 04, 2007 4:58 am Post subject:
Quote:
do you mean the DCB parameters are not required
Yes - as per the manual. For several years now (since the mid 90s?) LRECL, RECFM and BLKSIZE (and probably others) are stand-alone parameters i.e. they do not need to be coded as sub-parameters of DCB _________________ Utility and Program control cards are NOT, repeat NOT, JCL.
Joined: 26 Nov 2002 Posts: 12377 Topics: 75 Location: San Jose
Posted: Fri May 04, 2007 8:51 am Post subject:
A 3390-n device has a capacity of 56,664 bytes per track,of which 55,996 bytes are accessible by applications programmers. And 1 cylinder is 15 tracks.
So let us take the accessible bytes in a track which is 55,996.
Code:
1 Cylinder = 55,996 * 15 = 839,940 bytes.
so 1000 cylinders = 839,940 * 1000
1 Megabyte = 1,048,576 (2 to the 20th power) bytes.
Disk space is measured in cylinders for CMS, in megabytes for UNIX, and in tracks for MVS. For an approximate conversion between cylinders and megabytes, use the formula "1 cylinder = 600 KB" (1 KB = 1024 bytes, 1024 KB = 1 MB). For conversion between cylinders and tracks, use the formula "1 cylinder = 15 tracks".
The megabyte formula will actually provide more UNIX disk space than needed. The true number of bytes per cylinder varies as a result of arbitrary choices made by you when creating the files on CMS or when formatting the minidisk.
The following table lists some representative disk quotas in cylinders and in megabytes
Joined: 01 Feb 2007 Posts: 1075 Topics: 7 Location: At Home
Posted: Fri May 04, 2007 9:38 am Post subject:
MVS uses cyls, tracks, blocks u-name-it. I should think CMS (which I think runs under VM) uses probably the same. Never tried UNIX allocations
but as Koluso said 55996 bytes per track, 15 tracks per cyl number of cyls per 3390 depends on version of 3390. _________________ Utility and Program control cards are NOT, repeat NOT, JCL.
Joined: 03 Dec 2002 Posts: 579 Topics: 1 Location: Iowa, USA
Posted: Mon May 07, 2007 8:13 am Post subject:
Be mindful that the actual usable bytes per track depends greatly on physical blocksize written. Small blocks waste alot of space on each track due to the architecture.
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