Starting with z/OS 2.1 and continuing with z/OS 2.2, IBM has improved the performance of the Erase-On-Scratch (EOS) function over the pre-z/OS 2.1 releases by increasing the number of tracks that can be "erased" in each channel program from 1 to 255 to 12,240. The good news is that with those changes (on the software side) there was a drastic reduction in both elapsed time as well as an I/O count reduction, but these I/O operations are asynchronous and as such, most customers are concerned about suffering the performance hit that it takes to implement EOS, especially with replicated DASD. IBM believes that there is a lot of latent interest in using this function, but most customers are simply not using it because of the potential performance impact, including myself. And even if customers are using it, they are using it only for a subset of data sets. IBM would like to drive the use Erase-On-Scratch use up and get most, if not all customers using it because of the security exposure that exists and that IBM would like to eliminate.
IBM has been having some internal discussions about improvements that revolve around a combination of hardware/microcode and z/OS software changes that, if implemented in z/OS and the DASD subsystem, would bring the overhead of using EOS down to the point where the overhead would not be noticed. But... the folks involved in bringing that to market need our help. There's an RFE that we can vote for that would show the level of interest in this function. If your Auditors or internal security folks are concerned about residual data on DASD and would like to see you using EOS but you are concerned about the overhead, please consider voting for the following enhancement to help bring this new functionality to market: https://www.ibm.com/developerworks/rfe/execute?use_case=viewRfe&CR_ID=134047 Thanks! Larre Shiller US Social Security Administration ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
