It is not the exact power of 2 from 15 bits on. 2 **15 is 32767, but IBM only allowed 32760 cylinders. 2**16 is 64K, but IBM only allowed 65.520 cylinders. EAVs are a multiple of 1113 cylinders under 2 **18 then 2 **20 limits and eventually 2 **28, I listed the highest multiple.
On Tue, Jun 11, 2013 at 7:12 PM, DASDBILL2 <[email protected]> wrote: > > The numbers of cylinders (column 2) that can be represented by the number of > bits in column 1 are correct from 7 to 14 bits, but the table has slightly > wrong values from 15 bits and higher. And 7 of the values are odd numbers, > which can never happen. > > Bill Fairchild > Franklin, TN > > > ----- Original Message ----- > From: "Mike Schwab" <[email protected]> > To: [email protected] > Sent: Tuesday, June 11, 2013 6:04:57 PM > Subject: Re: Data volumes > > On Tue, Jun 11, 2013 at 8:30 AM, Pew, Curtis G > <[email protected]> wrote: >> On Jun 11, 2013, at 8:18 AM, Paul Gilmartin <[email protected]> >> wrote: >> >>> 2**18 + 2**9 + 12. A peculiar number. I wonder how they chose >>> that? >> >> For what it's worth, that's 236 * 1113, the latter being the size of a 3390 >> mod 1. I don't know why they went with 236 (2**2 * 59) though. >> >> -- >> Curtis Pew ([email protected]) > > Highest multiple of 1113 that is under 2 ** 18 (using 18 bits of the > x'ccccCCChrr' field (is c'CCHHR' for non-EAV volumes.) > Here is a list of OS/360 to z/OS x.xx volumes by number of bits used > for number of cylinders. > > http://www.hercules-390.eu/hercload.html > Bits Cyls Model GB > 3390-Model/ Bits used First used > 7 128 0.1150 0.109 M0.11 > B07 > 8 256 0.2300 0.218 M0.21 > B08 23## (OS/360) > 9 512 0.4600 0.435 M0.46 > B09 3330-1 > 10 1,024 0.9200 0.870 M0.92 B10 > 3330-11 > 11 2,048 1.8401 1.741 M1.84 B11 > 3380-2 > 12 4,096 3.6801 3.481 M3.68 B12 > 3380-3 > 13 8,192 7.3603 6.963 M7.36 B13 > 14 16,384 14.7206 13.926 M14.7 > B14 3390-9 12/1993 > 15 32,760 29.4340 27.845 M29.4 > B15 3390-27 OS/390 V2.10 > 16 65,520 58.8679 55.689 M58.8 > B16 3390-54 OS/390 V2.10 > 17 130,221 117.0000 110.682 M0117 > B17 EAV1 > 18 261,555 235. 222.310 > M0235 B18 EAV2 3390-EAV 2bits z/OS V1.10 > 19 524,223 471. 445.566 > M0471 B19 EAV3 > 20 1,048,446 942. 891.132 > M0942 B20 EAV4 3390-EAV 4bits z/OS V1.13 > 21 2,096,892 1,884. 1,782.264 > M1884 B21 EAV5 (future) > 22 4,193,784 3,768. 3,564.528 > M3768 B22 EAV6 3390-EAV 6 bits z/OS V2.0x > 23 8,387,568 7,536. 7,129.056 > M7536 B23 EAV7 > 24 16,776,249 15,073. 14,259.058 M15073 B24 EAV8 > 3390-EAV 8 bits z/OS V2.1x > 25 33,553,611 30,147. 28,519.062 M28519 B25 EAV9 > 26 67,108,335 60,295. 57,039.070 M60295 B26 EAV10 > 3390-EAV 10 bits z/OS V3.0x > 27 134,216,670 120,590. 114,078.140 M120590 B27 > EAV11 > 28 268,434,453 241,181. 228,157.226 M228158 B28 > EAV12 3390-EAV 12 bits > z/OS V3.1x > -- Mike A Schwab, Springfield IL USA Where do Forest Rangers go to get away from it all? ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
