IBM TS2340 User Guide - Page 342

IBM Tape Diagnostic Tool Full Write The Full Write function writes the entire cartridge with a given block size either with compressible or incompressible data and output performance data. Attention: The Full Write function erases data on the cartridge that is used for the test. Notes: 1. The Full Write function takes approximately 2 hours when writing incompressible data, less time for compressible data. 2. The Full Write function runs only on tape drives, not on autoloaders or libraries. The Full Write test can be used to: v Demonstrate that the drive is capable of writing the full amount of data on a cartridge. v Reveal system performance bottlenecks. Full Write firsts runs the test with incompressible data first, then runs the test with compressible data. If no difference in overall performance is observed, then probably there is a bandwidth limitation caused by the system or cabling or HBA. v Identify system issues with compression. Compression is always switched on during the full write. When run with compressible data, the output shows the compression rate. If that is higher than 1.0 but your system does not appear to be able to compress data on the cartridge, check your device driver and software settings to see if they disable compression. To perform a full write on tape drives within a library, the library must be in online mode. 1. After selecting the device you want to write to, start the Full Write function by selecting Test -> Full Write from the actions toolbar. 2. Click OK to start the full write. ITDT-GE then displays the Full Write screen. If no cartridge is inserted, ITDT-GE prompts to insert a cartridge. Either insert a cartridge and click OK or stop by clicking the Abort button. Note: If ITDT-GE detects data on the cartridge, it displays the following message (Figure 97 on page 325): 324 IBM Tape Device Drivers Installation and User's Guide