On Tue, May 15, 2018 at 11:06 AM, Mike Schwab <[email protected]> wrote:
> On Tue, May 15, 2018 at 8:33 AM, John McKown > <[email protected]> wrote: > > On Tue, May 15, 2018 at 7:57 AM, Kurt Quackenbush <[email protected]> > wrote: > > > >> On 5/15/2018 2:58 AM, Mike Fulton wrote: > >> > >>> Hi > >>> > >>> I know in ISPF under 3.2, if I am allocating a dataset and it is > >>> SMS-managed, I can specify the space in bytes (e.g. megabytes) > >>> instead of tracks or cylinders or blocks. Is there a similar way to > >>> do this from the TSO ALLOC command? Looking at the manual, I can't > >>> see it, but I would have thought if it could be done in ISPF, it > >>> could be done in TSO... > >>> > >> > >> It sure would be simpler if you could just specify the number of bytes, > >> but that's not how it works. Instead you specify the length of an > average > >> record (AVBLOCK) in bytes and the multiplier (AVREC). > >> https://www.ibm.com/support/knowledgecenter/en/SSLTBW_2.1.0/ > >> com.ibm.zos.v2r1.ikjc500/alloccmd.htm > > > > > > S > > o you simply set AVBLOCK to 1 and AVREC to number of bytes? > > It would include a lot of inter record gap space. > Even AVGREC=80 and using blocksize 8000 would add a lot of inter > record gap space. > I was thinking of doing something like: SPACE=(1,(1048576,1048576)),RECFM=U,BLKSIZE=27998,AVGREC=U to get about 1MiB of disk space. When I ran a job to do that, the dataset was allocated 19 tracks. 19*56K=1064K or about 1MiB. If I change the BLKSIZE= to 8000 instead, I get 22 tracks. So DADSM is properly calculating the inter-block gap to give me enough space to store about 1MiB of user data in my dataset, assuming that every block is BLKSIZE length. My first example is 1/2 track blocking, which is what I use a lot when I put the contents of a UNIX file into a z/OS dataset; especially the output from PAX. In the past, I used RECFM=FB,LRECL=1,BLKSIZE=27998 for PAX output because I was thinking that was a good way to indicate that the data was a "byte stream". > > -- > Mike A Schwab, Springfield IL USA > Where do Forest Rangers go to get away from it all? > > -- We all have skeletons in our closet. Mine are so old, they have osteoporosis. Maranatha! <>< John McKown ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
