From: David Masover Date: 2010-11-28T09:56:33+09:00 Subject: Re: Ruby 1.8 vs 1.9 On Saturday, November 27, 2010 02:47:12 pm Phillip Gawlowski wrote: > On Sat, Nov 27, 2010 at 7:50 PM, David Masover wrote: > > I suppose I expected people to be developing modern Linux apps that just > > happen to compile on that hardware. > > Linux is usually not the OS the vendor supports. Keep in mind, a day > of lost productivity on this kind of systems means losses in the > millions of dollars area. In other words, you need someone who will support it, and maybe someone who'll accept that kind of risk. None of the Linux vendors are solid enough? Or is it that they don't support mainframes? > >> And mainframes with vector CPUs are ideal for all sorts of simulations > >> engineers have to do (like aerodynamics), or weather research. > > > > When you say "ideal", do you mean they actually beat out the cluster of > > commodity hardware I could buy for the same price? > > Sure, if you can shell out for about 14 000 Xeon CPUs and 7 000 Tesla > GPGPUs (Source: http://en.wikipedia.org/wiki/Tianhe-I ). From that page: "Both the original Tianhe-1 and Tianhe-1A use a Linux-based operating system... Each blade is composed of two compute nodes, with each compute node containing two Xeon X5670 6-core processors and one Nvidia M2050 GPU processor." I'm not really seeing a difference in terms of hardware. > > All three of which suggest to me that in many cases, an actual greenfield > > project would be worth it. IIRC, there was a change to the California > > minimum wage that would take 6 months to implement and 9 months to > > revert because it was written in COBOL -- but could the same team really > > write a new payroll system in 15 months? Maybe, but doubtful. > > So, you'd bet the corporation Nope, which is why I said "doubtful." > just because you *think* it is > easier to do changes 40 years later in an unproven, unused, upstart > language? Sorry, "unproven, unused, upstart"? Which language are you talking about? > > But it's still absurdly wasteful. A rewrite would pay for itself with > > only a few minor changes that'd be trivial in a sane system, but major > > year-long projects with the legacy system. > > If the rewrite would pay for itself in the short term, then why hasn't > it been done? The problem is that it doesn't. What happens is that those "few minor changes" get written off as "too expensive", so they don't happen. Every now and then, it's actually worth the expense to make a "drastic" change anyway, but at that point, again, 15 months versus a greenfield rewrite -- the 15 months wins. So it very likely does pay off in the long run -- being flexible makes good business sense, and sooner or later, you're going to have to push another of those 15-month changes. But it doesn't pay off in the short run, and it's hard to predict how long it will be until it does pay off. The best you can do is say that it's very likely to pay off someday, but modern CEOs get rewarded in the short term, then take their pensions and let the next guy clean up the mess, so there isn't nearly enough incentive for long-term thinking. And I'm not sure I could make a solid case that it'd pay for itself eventually. I certainly couldn't do so without looking at the individual situation. Still wasteful, but maybe not worth fixing. Also, think about the argument you're using here. Why hasn't it been done? I can think of a few reasons, some saner than others, but sometimes the answer to "Why hasn't it been done?" is "Everybody was wrong." Example: "If it was possible to give people gigabytes of email storage for free, why hasn't it been done?" Then Gmail did, and the question became "Clearly it's possible to give people gigabytes of email storage for free. Why isn't Hotmail doing it?"