The following message is a courtesy copy of an article that has been posted to bit.listserv.ibm-main,alt.folklore.computers as well.
Anne & Lynn Wheeler <[EMAIL PROTECTED]> writes: > with the advent of PCs ... a lot of the cms personal computing migrated > to PCs ... although the (mainframe) virtual machine operating system > continues to survive ... and even had seen some resurgent in the early > part of this decade supporting large numbers of virtual machines running > linux ... somewhat in the "server consolidation" market segment > > recently, "server consolidation" has become something of a more widely > recognized buzzword ... pushing a combination of virtual machine > capability migrated to PC hardware platforms possibly in combination > with large BLADE form-factors farms ... where a business with hundreds, > thousands, or even tens of thousands of servers are consolidating into > much smaller space. re: http://www.garlic.com/~lynn/2007m.html#51 Is Parallel Programming Just Too Hard? note that in the 80s, there started to be the possibility of two-level "timesharing" dispatch/scheduling when some amount of the virtual machine capability migrated into the mainframe "hardware", ... commingly referred to now as LPARS (logical partitions). The hardware had to schedule/dispatch timeshare the virtual machine LPARS ... and within an LPAR could be a virtual machine operating system, also having to schedule/dispatch timeshare its virtual machines. something similar has to be going on the emerging PC-based genre of virtual machine implementations. one of the interesting dispatch/schedule evolution starts with single processor virtual machines running on single processor hardware ... then moving to single processor virtual machines running on multiple processor hardware ... things can get more complex when having to run multiple processor virtual machines running on multiple processsor hardware ... and it may not be possible to independently dispatch/schedule the different virtual processors of a virtual machine ... having possibly needing to dispatch/schedule multiple virtual processors (of a virtual machine) concurrently on multiple real processors. lots of past posts about multiprocessors, tightly-coupled, and/or compare&swap instruction http://www.garlic.com/~lynn/subtopic.html#smp ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
