Well, technically speaking, there never was a 3390-27. There was the 3390-1, 3390-2, 3390-3, and 3390-9 as actual physically orderable devices. The 3390-n for other values of "n" usually referred to either a multiplier over the size of a 3390-1, e.g.: a 3390-27 was 27x the number of cylinders of a 3390-1 (which was only 1113 cylinders, making a 3390-27 be 30051 cylinders==27x1113). The other was that the "-n" was for "gigabytes". A track on a 3390 device is 56K in size, sort of. There are 15 tracks per cylinder or 840K per cylinder. 27Gigabytes is 27,648M or 28,311,552K or 33,704 cylinders (rounded). But 33,704 is too big to fit in a signed halfword and so IBM decided to "round" it to 32760 cylinders. 32760 cylinders = 481,400 tracks = 27,518,400K =~ 3390-27.
IOW: This is IBM marketing having fun with us using rather poor math. -- John McKown Systems Engineer IV IT Administrative Services Group HealthMarkets® 9151 Boulevard 26 • N. Richland Hills • TX 76010 (817) 255-3225 phone • [email protected] • www.HealthMarkets.com Confidentiality Notice: This e-mail message may contain confidential or proprietary information. If you are not the intended recipient, please contact the sender by reply e-mail and destroy all copies of the original message. HealthMarkets® is the brand name for products underwritten and issued by the insurance subsidiaries of HealthMarkets, Inc. –The Chesapeake Life Insurance Company®, Mid-West National Life Insurance Company of TennesseeSM and The MEGA Life and Health Insurance Company.SM > -----Original Message----- > From: IBM Mainframe Discussion List [mailto:[email protected]] > On Behalf Of Martin, Larry D > Sent: Monday, November 19, 2012 10:59 AM > To: [email protected] > Subject: 3390-27 > > I just observed the following: > > IBM Disk capacity tables show 3390-27 as 32760 Cylinders > > Out DS8700 3390-27 disks have 30051 Cylinders > > Can anyone explain this? Was the DS8700 configured incorrectly? > > Thanks, .............Larry ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
