The following message is a courtesy copy of an article that has been posted to bit.listserv.ibm-main,alt.folklore.computers as well.
[EMAIL PROTECTED] (Wayne Driscoll) writes: > Not really answering either question, but on the topic of Q2, the recent > port of Open Solaris to System z was done only under z/VM, with no > attempt to get it to run under LPAR mode because of the increased amount > of work LPAR mode would have added (paraphrased from the company that > did the porting work). Now that the hard part of getting Linux to run > in an LPAR has been done, I don't see the need to eliminate it, but it > would be interesting to see the percentage of Linux on z usage in LPAR > vs z/VM. long ago and far away, similar arguments were made for both gold/au and aix/370. issue was that field engineering had lots of diagnostic, recording, and recovery requirements for servicing customer machines (EREP, RAS, etc). the effort to add mainframe EREP/RAS functionality to any of these ports was several times larger than just doing the straight forward port (while vm was able to satisfy the requirement, including for any of its guest operating systems). however, over the yrs, there has been more and more of virtual machine support functionality being moved into LPAR and service processor operation. slightly related recent post http://www.garlic.com/~lynn/2007t.html#77 T3 Sues IBM To Break its Mainframe Monopoly also in this post http://www.garlic.com/~lynn/2007u.html#8 Open z/Architecture or Not the reference to various OCO related material from vmshare archives, the reference to "TUCC's MVS/370 to MVS/XA conversion experiences" describes part of the success was having access to SIE and VM/SF information http://vm.marist.edu/~vmshare/browse?fn=OCOCME&ft=NOTE ... part of difficulty discussion from above ... The key to gaining performance from the primary guest operating system is the I/O Passthru feature of SIE. This allows the guest system to initiate I/O directly to the I/O subsystem without intervention from VM/SF. The SIE microcode assist is a documented feature, however the portion that supports I/O Passthru is not documented. As a result it took us two months to correct this problem. The problem was extraordinarly difficult to analyze, because the symptoms were noticeable only after the problem occured. We had all of MVS/370's I/O devices in I/O Passthru, including the Memorex 1270 devices. In certain circumstances, such as MVS disabling for 09x wait, VM/SF decided to remove all of the I/O from I/O Passthru. After taking all devices out of I/O passthru, VM/SF will then put them all back in. Performing this function requires that VM/SF perform a Modify Subchannel to each device to accomplish this. ... snip .. ---------------------------------------------------------------------- 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
