From owner-freebsd-questions@FreeBSD.ORG Sat Oct 23 07:03:54 2010 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id A60521065672 for ; Sat, 23 Oct 2010 07:03:54 +0000 (UTC) (envelope-from kline@thought.org) Received: from thought.org (plato.thought.org [209.180.213.209]) by mx1.freebsd.org (Postfix) with ESMTP id 583858FC1C for ; Sat, 23 Oct 2010 07:03:53 +0000 (UTC) Received: by thought.org (Postfix, from userid 1001) id 10ECDE838DF; Sat, 23 Oct 2010 00:03:53 -0700 (PDT) Date: Sat, 23 Oct 2010 00:03:53 -0700 From: Gary Kline To: Robert Bonomi Message-ID: <20101023070353.GC9331@thought.org> References: <201010230615.o9N6F5FJ017867@mail.r-bonomi.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <201010230615.o9N6F5FJ017867@mail.r-bonomi.com> X-Organization: Thought Unlimited. Public service Unix since 1986. X-Of_Interest: With 24 years of service to the Unix community. User-Agent: Mutt/1.5.20 (2009-06-14) Cc: freebsd-questions@freebsd.org Subject: Re: Greybeards X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 23 Oct 2010 07:03:54 -0000 On Sat, Oct 23, 2010 at 01:15:05AM -0500, Robert Bonomi wrote: > > > >Date: Fri, 22 Oct 2010 10:33:20 -0700 > >From: Gary Kline > > > > "TOS"? , LOL, ROFL ... > > Yawp. Really. TOS and DOS. Those _were_ the names the two OS varients > were known by. > > Not too long thereafter, IBM decided the minimum configuration would include > disk packs, And 0S/360 became the universal choice. > > > As for the 6400, it had 64k words of 60-bit (each word could hold 10 > characters in the internal CDC character set) memory. roughly 2x to 2.5x > the capacity of the 64k 32-bit words on the IBM. > > I programmed on the 6400, and it's big brother, the 6600, for a number of > years. An absolutely _lovely_ architecture at a high level it was a > beatutifully simple architecture, with a machine-language that you could > learn in an afternoon, if you'd had any exposure to _any_ other assemler > language. The instruction set was _so_ rational, you didn't need a "cheat > sheet" (aka, "green card", "yellow card", whatever) to keep track of what > was what. > > Now, admittedly, the closer you got to the hardware, the more "strange" the > machine got. It's the only machine I know of, where "CPU HALT" is an > _unpriviliged_ user-mode instruction. and one where user programs are > *expected* to use it to end every program. > > And, of course, the 6600 architecture (the 6600 was the original model, 6400s > were introduced later as a 'economy' version) as one other endearing > characteristic. It *can't*add*. At the hardware level, addition is done > by 'complement and subtract'. And the CPU clock is more than 10x faster > than memory read cycle. Memory is 32-way(!!) interleaved, to keep up. > > Oh yeah, the machine -really- annoyed computer-science purists. Up to > the limit of data that you oult fit in main memory, an optimized _bubble- > sort_ was faster than =any= other sorting algorithm. This came as a *RUDE* > surprise to more than one first-year C.S dept faculty member. There was > always some smart-*ss in the class who got the bubble-sort implementation > "right", and it ran in far less time than even quicksort. If you did > _careful_ benchmarking, you could see that when the data-sets got large > enough that the 'expected' (bubble-sort "loses") behavior _was_ there. > but the cross-over/break-even point was at a point that was _larger_ > than the maximum main memory that you could hang on a machine with only > an 18-hit address-space. Uuser apps were limited to only 17 bits of > addressing. > > It also freaked some people that you could copy a dataset that was > many times the size of main memory, using only _one_ buffer, and isusing > only *one* 'read" and *one* "write" instruction. The operating system > was 'management by committee' at the _hardware_ level, and could literally > be doing _20_ different things simultaneously. Start one member of the > 'committee' transferring data from the 'source' into the buffer, and hav > a -second- member transfering _out_ of the butter to the destination, > and just sit ack and watch them go at it. > > The 6600 also gets credit for being the first CPU where speed-of-light > limitqation had to be taken into consideration. roughly 40% of the data > "in" the CPU didn't have a fixed location, but was 'in transit' to where > it "would be" needed.. internal wiring of a particular insulation color > was _not_ 'field repairable'. you had to remove the wire entirely, and > replace it with a nother pice with the -specific- part number that came > from the factory. > Very interesting history. I never knew that the wordsize was 60 bits; hmm. The 6600 was designed by Seymour Cray, as you prob'ly know. Seymour was a hardcore EE who (at the time) thought that software was for pussies. No-need-for. No OS, no nothing. Seymour only cared about speed. -- Gary Kline kline@thought.org http://www.thought.org Public Service Unix The 7.90a release of Jottings: http://jottings.thought.org/index.php http://journey.thought.org