Path: csiph.com!x330-a1.tempe.blueboxinc.net!usenet.pasdenom.info!weretis.net!feeder4.news.weretis.net!usenet.ukfsn.org!not-for-mail From: Martin Gregorie Newsgroups: comp.lang.java.programmer Subject: Re: Arithmetic overflow checking Date: Sun, 10 Jul 2011 19:22:23 +0000 (UTC) Organization: UK Free Software Network Lines: 62 Message-ID: References: <015aeb15-57db-48ab-9cd4-77f8448b632f@w24g2000yqw.googlegroups.com> <2rydnez7l-H5BYnTnZ2dnUVZ_vGdnZ2d@earthlink.com> <9LWdnZH2hdfmyYvTnZ2dnUVZ_vidnZ2d@posted.palinacquisition> <1K2dnVVEK60FcoTTnZ2dnUVZ_hKdnZ2d@earthlink.com> NNTP-Posting-Host: 84.45.235.129 Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Trace: localhost.localdomain 1310325743 21494 84.45.235.129 (10 Jul 2011 19:22:23 GMT) X-Complaints-To: usenet@localhost.localdomain NNTP-Posting-Date: Sun, 10 Jul 2011 19:22:23 +0000 (UTC) User-Agent: Pan/0.133 (House of Butterflies) Xref: x330-a1.tempe.blueboxinc.net comp.lang.java.programmer:6058 On Sun, 10 Jul 2011 11:29:39 -0700, Patricia Shanahan wrote: > On 7/10/2011 11:07 AM, Martin Gregorie wrote: >> On Sun, 10 Jul 2011 10:53:09 -0400, David Lamb wrote: >> >>> On 08/07/2011 12:30 AM, Eric Sosman wrote: >>>> On 7/7/2011 8:51 PM, Peter Duniho wrote: >>>>> [...] >>>>> I would not worry about the "simple" or "efficient" criteria. IMHO, >>>>> if one is deciding to apply overflow checking to every computation, >>>>> one has already abandoned the hope of efficiency. >>>> >>>> I've used machines that raised overflow traps "for free," >>> ... >>>> (The machines I speak of were from forty-odd years ago >>> >>> When microprocessors started to arrive on the scene, a lot of >>> old-timey hardware folks said they'd forgotten 30+ years of hardware >>> design. When operating systems for computers based on said processors >>> came out, a lot of old-timey software folks said they'd forgotten 30+ >>> years of operating system design. We seem to still be suffering the >>> consequences. >> >> That happened not once, but twice. >> >> The first great leap backward was the minicomputer era, when the likes >> of the PDP-8 arrived with a single user, single tasking OS reminiscent >> of early computers, except they generally had teletypes instead of >> banks of switches and flashing lights. By then the better mainframes >> were multi- user, multitasking beasts. >> >> Then the first microcomputers arrived in the mid/late '70s. By this >> time the better minis had multi-tasking operating systems, but micros >> had re- implemented the earliest mini OSes - CP/M was near as dammit a >> copy of the old PDP-8 OS (RSTS?) from the late 60s - and the earliest >> micros even had switches and flashing lights (KIM-1, IMSAI 8080). By >> 1980 the minis were running UNIX but the latest and greatest micros had >> - drumroll - MS- DOS! >> >> >> > Only twice? Aren't you forgetting "smart" phones. One of the great > advances in Android is (Drum roll!) multitasking!!! > They don't count since, unlike minis and micros, their builders didn't retreat to the techno-stone age, ignore progress made to date, and build primitive OS by rubbing (metaphorical) sticks together. AFAIK all smartphones started an a more advanced level because they inherited better operating systems. IIRC these all originated on electronic memo pads such as Psion, HP and Palm Pilot made, and were all a lot more advanced than the likes of RSTS, CP/M, Flex09, etc. Leastwise, I don't think you can consider Symbian and whatever MS was calling the iPAQ OS at that stage any more primitive than the contemporary versions of MacOS, OS/2 or even Windows, though admittedly they were rather behind UNIX and its distant relations such as OS-9/68K. -- martin@ | Martin Gregorie gregorie. | Essex, UK org |