HP 3000 Manuals HP 3000 Manuals
MPE/iX versus MPE V Data Collection The collector programs for MPE/iX (SCOPEXL) and MPE V (SCOPE) have identical functions. The programs have different names to prevent a user from executing the wrong version of the collector on a system. You can use the same PARM files to define applications, identify systems, and set thresholds. The log files created on both systems have the same names: LOGGLOB, LOGAPPL, LOGPROC, LOGDISC, and LOGALRM. An additional log file, LOGINDX, is created with MPE/iX. It is very small and can appear to be empty (i.e. contain zero records). Do not purge it! The file contains the information necessary for rapid positioning into the other three log files. All log files are created by SCOPEXL when it is first run or are created by the UTILITY program. Since the data collected by SCOPE and SCOPEXL are compatible, you can expect the log files to grow at about the same rate (usually at an average rate of about 1 megabyte of data per day). MPE/iX allows 31 user-defined applications while MPE V allows only 15. There is a limitation when you move a raw or extracted MPE/iX log file to an MPE V system. EXTRACT will be able to extract application details for all applications, but will only extract application summaries for the first 16 applications. You will receive a warning message if you try to use the MPE V EXTRACT program to extract application summaries of a log file with more than 16 applications. MPE/iX provides 5 kilobytes of disc space for application definitions; MPE V provides 2 kilobytes of disc space. Logical Disc I/Os On MPE/iX systems, there is a relatively higher ratio of logical disc I/O to physical disc I/O than on MPE V systems. This is partly due to MPE/iX caching disc writes and reads, but to a larger degree, it is due to the two systems defining logical I/O differently. Under MPE V, a logical I/O occurs when the file system requests the I/O system to transfer a block of data to or from a disc file. Under MPE/iX, a read attempt or write attempt occurs whenever a program requests the file system to transfer a block of data. These transfers can occur at each record, at each block (if multirecord I/O is done), or not at all (if mapped files are used). The metric that records MPE/iX read/write attempts is comparable to the metric that records MPE V logical I/Os, but they are not equivalent.