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Simple answer .. Single level store means (essentially) that the physical configuration of the storage is hidden from all of the system except for those OS routines associated with disk I/O. Blocking is similar in concept to cacheing . . . even though a program will read one record at a time, a "block" of records is brought into the job memory area, speeding the the program access to the individual records. Hope this helps. >>> james@eaerich.com 01/08/03 03:54PM >>> On Wed, 8 Jan 2003, Leif Svalgaard wrote: > excuse me, but isn't the Single Level Store supposed to make all this > talk about blocking irrelevant? We used to hear that "traditional > computers" were worse than SLS because data had to transferred > from the disk into blocks of memory before being processed. SLS was > supposed to make that obsolete. No? Old 36 code has a lot of blocking parms in it, so blocking apparently made a difference. When disk is read it is read into something, that something is unlikely to be the CPU cache, even on a single level store system. The CPU can't do its work directly on the disk or even directly on the RAM. The read operation must store what it reads from disk somewhere where the cpu can merge the data with the instruction stream and then execute. James Rich _______________________________________________ This is the Midrange Systems Technical Discussion (MIDRANGE-L) mailing list To post a message email: MIDRANGE-L@midrange.com To subscribe, unsubscribe, or change list options, visit: http://lists.midrange.com/mailman/listinfo.cgi/midrange-l or email: MIDRANGE-L-request@midrange.com Before posting, please take a moment to review the archives at http://archive.midrange.com/midrange-l. THIS MESSAGE IS INTENDED ONLY FOR THE USE OF THE INDIVIDUAL OR ENTITY TO WHICH IT IS ADDRESSED AND MAY CONTAIN INFORMATION THAT IS PRIVILEGED, CONFIDENTIAL AND EXEMPT FROM DISCLOSURE UNDER APPLICABLE LAW. If the reader of this message is not the intended recipient, or the employee or agent responsible for delivering the message to the intended recipient, you are hereby notified that any dissemination, distribution, copying, downloading, storing or forwarding of this communication is prohibited. If you have received this communication in error, please notify us immediately via email and delete the message from your computer files and/or data base. Thank you.
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