In today's environment, the "mod number" is simply the size of the device in cylinders (more or less). The original 3390 mod 3 had 3339 cylinders. There was also a 3390-1 which had 1113 cylinders and a 3390-2 which had 2226. The original mod 9 had 9*1113 or 10017 cylinders, but was "slower" than the other 3390s. So, the convention more or less became that a 3390-n device contained "n" time 1113 cylinders. Today the "mod number" is basically meaningless because most DASD subsystems can be set up to have disk with any number of 3390 format cylinders that you want. I remember when we had EMC and "mini disks" which were only about 200 cylinders for small, highly active datasets. That is no longer done much because of PAV and HyperPAV volumes. It was done to get more parallel I/O because, before PAV, you could only have one I/O active to a DASD volume at a time. PAV allows multiple I/Os to be active to the same volume by assigning multiple device numbers to the same logical volume.
So, to see how many "mod n" volumes you have, look at the total number of cylinders on each volume. On Sat, 2011-04-30 at 09:33 +0530, jagadishan perumal wrote: > Hi, > > Could anyone please let me know to verify that in the *DASD* Pool If i have > *Mod3* or Mod9. Also, I would like to know if its there any way to check if > any dasd Mods not in use. > > Could you please let me know if it requires more informations. > > Regards, > Jags > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to [email protected] with the message: GET IBM-MAIN INFO > Search the archives at http://bama.ua.edu/archives/ibm-main.html -- John McKown Maranatha! <>< ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
