> -----Original Message----- > From: IBM Mainframe Discussion List > [mailto:[EMAIL PROTECTED] On Behalf Of Dana Mitchell > Sent: Thursday, July 12, 2007 2:37 PM > To: IBM-MAIN@BAMA.UA.EDU > Subject: Re: Track size and maximum single volume data set size > > > This raises another question. Now that all modern DASD is > some flavor of > 3380 or 3390 geometry emulated via RAID, why is it neccessary > to emulate the > gaps between blocks when writing blocks to a track? Since > the microcode is > emulating track size and cylinders etc, why not allow full > utilization of > the tracksize regardless of block size? or do access methods have > calculations built in for allowing for the gaps? > > Dana Mitchell
Your speculation is correct. Access methods calculate the amount of space left on a track (TRKBAL?). This is so that they know whether the block to be written to the end of a dataset (a new physical block) will fit on the current track or needs to be written to the first record of the next track. -- John McKown Senior Systems Programmer HealthMarkets Keeping the Promise of Affordable Coverage Administrative Services Group Information Technology The information contained in this e-mail message may be privileged and/or confidential. It is for intended addressee(s) only. If you are not the intended recipient, you are hereby notified that any disclosure, reproduction, distribution or other use of this communication is strictly prohibited and could, in certain circumstances, be a criminal offense. If you have received this e-mail in error, please notify the sender by reply and delete this message without copying or disclosing it. ---------------------------------------------------------------------- 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
