On 20 July 2016 at 21:29, Paul Koning <paulkon...@comcast.net> wrote: > I don't remember the earlier ARM designs, but it was my impression that DEC's > StrongARM was the one that made really large strides in low power (especially > power per MHz of clock speed). Interestingly enough, StrongARM was one of > the few (and the first?) independent designs; it used the ARM architecture > specification but not the actual logic design as others did.
Hmm. That wasn't my impression at the time, no. The big deal with StrongARM was that it had a dramatically increased speed -- whereas Acorn ARMs ran from 8MHz in my original Archimedes A305 to 12MHz for the first SoC ones (A3010 with ARM 250) to 25MHz for the ARM3-powered A5000, Digital's first StrongARM ran at 100-200MHz. To keep the core fed with data at this ridiculous speed, it had onboard L1 instruction & data caches. http://www.zdnet.com/pictures/decs-40-years-of-innovation/10/ https://www.netogram.com/strongarmprocessor.htm Original PR: http://www.cpushack.com/CIC/embed/announce/DigitalStrongARMIntro.html Self-modifying code could write back to and thus run from the cache before it was propagated to the main RAM, which meant that some RISC OS code had to be rewritten. E.g. http://www.riscos.com/ftp_space/370/index.htm The "Kinetic" StrongARM upgrade for the RISC PC therefore had RAM on the CPU daughterboard, as the motherboard RAM was not even close to fast enough. http://www.riscos.info/index.php/Kinetic So at least in the marketing to the Acorn user community, no, power draw wasn't even mentioned. It never came up. The original ARMs were low-power, and so was StrongARM. StrongARM wasn't a big win for the Newton, inasmuch as the Original MessagePad (OMP) had an ARM610 in it. The Newton 2000 was the first model with a StrongARM but it was merely an upgraded CPU for the newer hardware. -- Liam Proven • Profile: http://lproven.livejournal.com/profile Email: lpro...@cix.co.uk • GMail/G+/Twitter/Flickr/Facebook: lproven MSN: lpro...@hotmail.com • Skype/AIM/Yahoo/LinkedIn: liamproven Cell/Mobiles: +44 7939-087884 (UK) • +420 702 829 053 (ČR)
