Subject: RE: How to precisely calculate the number of bytes per track for a
From: Kevin Corkery (firstname.lastname@example.org)
Date: Fri Aug 19 2011 - 09:51:59 EDT
Maybe this may be of help ... http://publibz.boulder.ibm.com/cgi-bin/bookmgr_OS390/BOOKS/am3u1001/B.1.2 http://publibz.boulder.ibm.com/cgi-bin/bookmgr/BOOKS/IESVGE60/7.4.3?SHELF=IE SVSE80&DT=20100803123026#TBLCISDATC The first is the 3390 track capacity chart for sequential files and the second is the VSAM capacity (based on CISZ) for various ECKD devices. -----Original Message----- From: owner-vse-l@Lehigh.EDU [mailto:owner-vse-l@Lehigh.EDU] On Behalf Of Beggs, Beth A. Sent: Friday, August 19, 2011 9:29 AM To: VSE Discussion List Subject: RE: How to precisely calculate the number of bytes per track for a Yes, those multiple posts were a combination of user and system error! I just removed the dups. Your answer does help. In addition to straight VSAM space, we use EPIC disk which is offloaded to (virtual 3490) tape. We do not have any tape blocksize in excess of 32767. Is that also an obsolete limitation? -----Original Message----- From: owner-vse-l@Lehigh.EDU [mailto:owner-vse-l@Lehigh.EDU] On Behalf Of Bo Sent: Friday, August 19, 2011 9:23 AM To: VSE Discussion List Subject: Re: How to precisely calculate the number of bytes per track for a Beth; I have noticed that you have opened a number of topics with this same question, I am presuming you are anxious for an answer. The capacity of a 3390 track is a constant, "Every 3390 disk volume contains 56,664 bytes per track, 15 tracks per cylinder and 849,960 Bytes per Cylinder." The CISIZE or BlockSize is the variable which determines how much data you can store on a device. In the old days a Blocksize was limited to 32K, if you had the "maximum" block size of 32,0000+ bytes you could write one block per track, this made the other 24,000 bytes useless and you wasted 2/3 of each track. To utilize a dasd device to it's fullest you should use a blocksize or CISIZE that allows for the maximum records per track. If your CISIZE is the 23,552 or 45,056 you indicated you will still lose around 10k per track. I like to use 18000 as a guideline, gets me 3 blocks per track with a minimum of waste. Hope that helps. NOTICE: This email message is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply email and destroy all copies of the original message. This message has been content scanned by the Axway MailGate. MailGate uses policy enforcement to scan for known viruses, spam, undesirable content and malicious code. For more information on Axway products please visit www.axway.com.
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