On Sat, 20 Apr 2002, Dave Jones wrote: > > -----Original Message----- > > From: Linux on 390 Port [mailto:[EMAIL PROTECTED]]On Behalf Of > > Hall, Ken (ECSS) > > Sent: Friday, April 19, 2002 12:13 PM > > To: [EMAIL PROTECTED] > > Subject: LinuxWorld Article series > > > > > > Anyone seen this? > > > > Aside from some (fairly glaring) technical inaccuracies, I can't > > see much I'm qualified to dispute. > > > > http://www.linuxworld.com/site-stories/2002/0416.mainframelinux.html > > > > But the "glaring technical inaccuracies" lead me to question his conclusions > about Linux on S/390. I suspect that > while he knows a great deal about the Unix environment and the typical Unix > user mindset, his grasp of the "mainframe" > world is limited, to say the least. He seems to fixate on the mainframe a > "batch-oriented" and Unix as interactive, and > that "interactive" doesn't work well on mainframes. He obviously has never > used CMS on VM (or CP/VM as he calls it...); > it's as interactive and responsive as any Linux system I've used. And his > statement that TSO and CMS "load as batch jobs" is just pure nonsense...... > > One statement struck me as clearly incorrect is the following: > > "In contrast, most mainframe control environments, including loadable > libraries and related systems level applications, are written and maintained > very close to the hardware -- usually in PL/1 or assembler but often with > handwritten or at least > "tweaked" object code -- to use far fewer cycles than their C language Unix > equivalents. > > This statement is wrong on two separate counts: > > 1) most mainframe programming (well above 50%) is still done in COBOL, with > PL/I, Assembler, Fortran, etc. splitting the rest. > 2) PL/I is lots of things, but "close to the hardware" ain't one of them. > :-) > > Overall this article appears to be not so much concerned with Linux running > on a S/390 environment, but a diatribe against > mainframes in general and the overall superiority of SUN boxes. That seems > to be the whole thrust of the paragarphs on > "mutually contingent evolution." (whatever that is.....). > > I suspect that Paul Murphy is a shill for SUN.
I found it interesting that he wrote about CP/40. That was the first example of a 360-style operating system using virtual memory with the equivalent of modern TLBs. [It had been done on other architectures.] The hardware was a one-of created for the Cambridge Scientific Center (Mass). And CP/67 was hosted virtually, and CP/67 begat VM/370, and VM/370 begat ..... So it is interesting but not terribly important to current understanding. He got the bit about CP/67->VM/370 wrong, too, calling it CP/VM. [Brown University had a VM/360, but I digress.] My conclusion is he read/skimmed a history, such as Melinda Varian's history of VM and folded it in without real knowledge or anyone to proofread the result. It did make me tend to disbelieve any conclusions. If the author couldn't understand and abstract (with credit) a well written history, it tends to suggest he doesn't understand the current environment. Anyone with half a brain can see that IBM bet mucho $$$ on Linux/390 and have sold a lot of machines and acquired a lot of mindshare... in some quarters they are approaching cool status. Big bet with a big payoff. There is a lot of stuff bubbling around in IBM also. They have some top guys working on NUMA machines that are regularly collaberating (sending code to) the Linux kernel development tree. john alvord
