Path: csiph.com!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Lynn Wheeler Newsgroups: alt.folklore.computers Subject: Re: Emulating vintage computers Date: Sat, 28 Sep 2024 14:01:37 -1000 Organization: Wheeler&Wheeler Lines: 26 Message-ID: <87r0931g66.fsf@localhost> References: <87tte2s1hu.fsf@localhost> <87v7yf1iw7.fsf@localhost> MIME-Version: 1.0 Content-Type: text/plain Injection-Date: Sun, 29 Sep 2024 02:01:40 +0200 (CEST) Injection-Info: dont-email.me; posting-host="2e0f1dff49e9949eda1a035847a5d7c4"; logging-data="1532464"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+61kLcdJmXh+9BpfBlZ5Q4HW70u6QTOts=" User-Agent: Gnus/5.13 (Gnus v5.13) Cancel-Lock: sha1:0xlCc3K4F9Mjcp2x03VxPfZFce8= sha1:krFJNHCgPkw37jKzjLeJ/oitRWU= Xref: csiph.com alt.folklore.computers:227173 emulation trivia Note upthread mentions helping endicott do 138/148 ECPS ... basically manual compiling selected code into "native" (micro)code running ten times faster. Then in the late 90s did some consulting for Fundamental Software https://web.archive.org/web/20240130182226/https://www.funsoft.com/ What is this zPDT? (and how does it fit in?) https://www.itconline.com/wp-content/uploads/2017/07/What-is-zPDT.pdf More recent versions of zPDT have added a "Just-In-Time" (JIT) compiled mode to this. Some algorithm determines whether a section of code should be interpreted or whether it would be better to invest some more initial cycles to compile the System z instructions into equivalent x86 instructions to simplify the rocess somewhat). This interpreter plus JIT compiler is what FLEX-ES used to achieve its high performance. FLEX-ES also cached the compiled sections of code for later reuse. I have not been able to verify that zPDT does this caching also, but I suspect so. ... snip ... -- virtualization experience starting Jan1968, online at home since Mar1970