Serena StarTool IOO
I/O Optimizer
As an OS/390 Performance professional, you have long known that the best manual tuning cannot produce
the performance savings of an automated and dynamic tuning utility. However, until now, no one single
integrated and comprehensive tool existed to tune all of your I/O processing with one easy to maintain
approach. SerenaT StarToolŪ IOO, I/O Optimizer, (formerly known as ULTIMIZERŪ) is the most comprehensive, 
cost-effective, fastest and easiest way to achieve total, automated system tuning.
Serena StarTool IOO is an integrated optimization system that automatically and dynamically tunes the major components of OS/390's I/O processing functions to achieve dramatic throughput improvements both in batch and on-line. It is the ultimate I/O throughput optimizer for OS/390. It is based on a proprietary analysis and intelligence gathering process during OPEN processing and I/O request to any VSAM or SAM (QSAM, BSAM and EXCP) dataset. Serena StarTool IOO delivers the performance needed for applications that operate in today's fast-changing eBusiness environment.
VSAM Optimization
Eighty percent (80%) of all VSAM mainframe applications use Non-Shared Resources (NSR) because most only support NSR. Serena StarTool IOO allows pro-grams written in any language (including COBOL) to use Local Shared Resources (LSR) when the program is dynamically or randomly accessing a VSAM file. Serena StarTool IOO builds the optimal number of LSR buffers to maximize performance. Most indexes are placed in main memory to reduce the number of physical I/Os to access a logical record. If sequential processing is requested, the number of NSR buffers for read-ahead processing is provided. LSR and NSR buffers are built above-the-16M-line to alleviate virtual storage constraints in the private area. For LSR, expanded storage using hiperspace buffering is automatically and transparently used when the file size is larger than the LSR pool.
Dynamic Memory Management
For those programs that are coded in assembler and already use native LSR, the perfect quantity of above-the-16M-line buffers and hiperspaces are transparently allocated based on file size. For all LSR processing (NSR-LSR or LSR native), a separate LSR pool is used for each file (up to 255 LSR pools transparently allocated) to eliminate buffer stealing. When applica-tions change processing modes from Direct to Sequential, the Serena StarTool IOO detects this and re-optimizes tuning parameters.
Sequential Optimization
Serena StarTool IOO dynamically optimizes SAM files to provide the best throughput and response time for I/O requests.
Blocking
Most sequential QSAM, SAM and EXCP processing is highly dependent upon efficient blocksizes. System Determined Blocksizes can not reblock all of a shop's sequential files. Serena StarTool IOO replaces or enhances SDB's reblocking function and performs reblocking on all sequential data sets, including managing programs with hard-coded DCB's. The product reblocks all device types including tape data sets and reblocks without any JCL changes. The physical blocksize is attached dynamically and automatically managed regardless of what logical blocksize the program is dependent upon. Therefore, even all SORT products, FOCUS files, SAS sequential files and all QSAM and BSAM sequential files are optimized. Serena StarTool IOO is smart enough to re-block only 35% of all your eligible data sets but achieve 90% of the potential savings.
Buffer Management
Serena StarTool IOO dynamically optimizes buffers and Start I/O's for QSAM, BSAM and sequential EXCP I/Os. Specifically, it optimizes physical sequential data sets, permanent and temporary, including data sets generated by most utilities (e.g.: IEBGENER, etc.). It improves QSAM, BSAM and EXCP performance as much as 75%, saves up to 50% elapsed time for DB2 Unloads and Reloads and saves up to 40% elapsed time for IDMS sweeps.
Built in Intelligence
Serena StarTool IOO contains a database of information containing parameters and values that deliver the best I/O performance by type of device by type of access. Customer can easily override the rules by keying in their own parameters, or by excluding a dataset or jobname from the optimization process. Most users, however, use the default parameters and achieve outstanding results from the I/O optimization.
Summary
This solution automates the I/O tuning efforts, increases the level of benefits received from practicing performance management and boosts user productivity. By using Serena StarTool IOO, enterprise IS organizations can help to ensure application efficiency and responsiveness throughout the life of their OS/390-based mission-critical applications, thereby controlling costs, satisfying customers, and supporting growth. Before you decide you need a new CPU, additional DASD or start a man-ual system tuning project, find out your true capacity and performance potential with Serena StarTool IOO.
StarTool is a registered trademark of SERENA Software, Inc. Serena is a trademark of SERENA Software, Inc. All other products or company names are used for identification purposes only, and may be trademarks of their respective owners.