z390 PTF v1.4.00e now available for download from www.z390.org has new VSAM KSDS AVL balanced tree insert support. For details and download link with InstallShield support for Windows visit:
http://z390.sourceforge.net/z390_Download_Archive.htm This PTF contains single RPI 806 enhancement to z390 VSAM support to add AVL balanced tree insertion for KSDS records. It includes new regression test program vsam\test\KSF2TST4.MLC which adds 1000 records in pseudo random sequence and then retrieves and lists them in ascending sequence using key access. This process creates a balanced tree with 10 levels (2**10 = 1024). The I/O required is about 10 writes per record. With the z390 VSAM VCB cache buffering option on, most rereads are avoided With this new support VSAM can now be used as a record sorting tool with the performance characteristics of a shell sort with I/O proportional to N * log2 N. VSAM has been updated to include AVL tree statistics on the STATS optional STA statistics file. The TRACEV option has been updated to include tracing of AVL height updates and rotations. The new support also includes verification of all KSIR record double links and branch height values to catch any file integrity problems. To run the new regression program, install z390 v1.4.00, then v1.4.00e, double click on z390 GUI icon, and enter the command vsam\test\KSF2TST4 STATS. See the following web page for high level explanation of AVL trees and the required rotations to maintain balanced tree after each insert: http://sky.fit.qut.edu.au/~maire/avl/System/AVLTree.html This AVL support was an intensive 10 day effort starting from scratch as all I knew 10 days ago was that trees could be balanced but I didn’t know what an AVL tree was. Thanks to Google and the Queensland University of Technology web page, I’ve had a quick on the job learning experience. There is much the rotation diagrams don’t say about the implementation details. Check out the vz390.java source for details on how it works. Also many thanks to the name sake G.M. Adelson-Velsky and E.M. Landis, who published it in their 1962 paper "An algorithm for the organization of information." Be sure and attend the SHARE Conference session 8194 next Monday, February 25, 2008 at 4:30 in Orlando Florida if you would like to learn more about z390 VSAM and CICS support. Both Melvyn Maltz and I will be speaking and perhaps we can organize a BOF on the subject for those interested. All feedback welcome! Hope to meet you at SHARE. Don Higgins mailto:[EMAIL PROTECTED] http://don.higgins.net ---------------------------------------------------------------------- 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
