Path: ...!news.iecc.com!.POSTED.news.iecc.com!not-for-mail From: John Levine Newsgroups: comp.arch Subject: Re: architectural goals, Byte Addressability And Beyond Date: Fri, 31 May 2024 19:44:49 -0000 (UTC) Organization: Taughannock Networks Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Injection-Date: Fri, 31 May 2024 19:44:49 -0000 (UTC) Injection-Info: gal.iecc.com; posting-host="news.iecc.com:2001:470:1f07:1126:0:676f:7373:6970"; logging-data="28970"; mail-complaints-to="abuse@iecc.com" In-Reply-To: Cleverness: some X-Newsreader: trn 4.0-test77 (Sep 1, 2010) Originator: johnl@iecc.com (John Levine) Bytes: 2416 Lines: 27 According to John Savard : >On Thu, 30 May 2024 03:25:14 -0000 (UTC), John Levine > wrote: > >>I do not entirely understand why IBM keeps adding special purpose >>instructions to z. Maybe it's partly marketing, but they have a >>largely captive audience so it has to be more than that. > >One possibility is to _keep_ that audience captive even after all the >patents expire that are applicable to machines with the z/Architecture >in its current state, if you are reluctant to believe that these new >instructions genuinely improve performance. Back in the last millenium there were a bunch of companies that made clones of IBM mainframes. They all failed. It's the whole ecosystem of hardware and software, not just individual features that keep the customers nor patents. I have to say I'm somewhat surprised that IBM has put a lot of effort into running linux on zSeries, since that's about as un-captive as you can get. I would imagine that for some kinds of heavily threaded workloads they could be competitive since the z machines have upwards of a hundred CPUs with a shared mostly consistent cache. -- Regards, John Levine, johnl@taugh.com, Primary Perpetrator of "The Internet for Dummies", Please consider the environment before reading this e-mail. https://jl.ly