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From: krewat@kilonet.net (Arthur Krewat)
Subject: [TUHS] RIP John Backus
Date: Sat, 17 Mar 2018 14:52:29 -0400	[thread overview]
Message-ID: <1881ddbc-690a-2901-a68e-91334322065d@kilonet.net> (raw)
In-Reply-To: <ecea8e70-4256-2476-1e3e-aa942a8627f9@mcjones.org>

On 3/17/2018 1:49 PM, Paul McJones wrote:
> It first ran on the IBM 704, whose index registers subtracted (as did 
> the follow-on 709, 7090, etc), so array indexing went from higher 
> memory addresses to lower.

Leave it to IBM to do something backwards.

Of course, that was in 1954, so I can't complain, it was 11 years before 
I was born. But that's ... odd.

Was subtraction easier than addition with digital electronics back then? 
I would think that they were both the same level of effort (clock 
cycles) so why do something obviously backwards logically?

ak


  reply	other threads:[~2018-03-17 18:52 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <mailman.19.1521302091.3788.tuhs@minnie.tuhs.org>
2018-03-17 17:49 ` Paul McJones
2018-03-17 18:52   ` Arthur Krewat [this message]
2018-03-18  3:39     ` Greg 'groggy' Lehey
2018-03-18  7:35     ` Otto Moerbeek
2018-03-18 13:33 Noel Chiappa
     [not found] <mailman.21.1521314548.3788.tuhs@minnie.tuhs.org>
2018-03-17 20:01 ` Paul McJones
2018-03-17 20:14 ` Paul McJones
2018-03-17 22:27   ` Steve Johnson
     [not found] <mailman.17.1521243734.3788.tuhs@minnie.tuhs.org>
2018-03-17 14:47 ` Paul McJones
2018-03-17 15:54   ` Dave Horsfall
  -- strict thread matches above, loose matches on Subject: below --
2018-03-16 21:52 Dave Horsfall
2018-03-16 23:42 ` Dan Stromberg
2018-03-17  0:08   ` Dave Horsfall
2018-03-17  0:26     ` Arthur Krewat
2018-03-17  0:36       ` Dave Horsfall
2018-03-17  1:40       ` Charles H Sauer
2018-03-17  1:57 ` Nemo
2018-03-17  7:20 ` Bakul Shah
2018-03-17 13:43 ` Clem Cole
2018-03-17 17:06   ` Steve Simon
2018-03-17 19:15     ` Pierre DAVID
2018-03-17 19:41       ` Charles Anthony
2018-03-18 11:02       ` Steve Simon
2018-03-17 19:22   ` Tim Bradshaw
2018-03-17 19:28   ` Mike Markowski
2018-03-18 18:51 ` Paul Winalski
2018-03-18 21:07   ` Clem Cole
2018-03-19 14:50     ` Dan Cross
2018-03-19 15:43       ` Clem Cole
2018-03-19 15:46         ` Clem Cole
2018-03-19 17:39           ` Paul Winalski
2018-03-19 17:43             ` George Michaelson
2018-03-19 18:16               ` Steve Nickolas
2018-03-19 17:48             ` Clem Cole
2018-03-19 17:59               ` Jon Forrest
2018-03-19 18:40                 ` Tom Ivar Helbekkmo
2018-03-19 19:40                   ` Arthur Krewat
2018-03-19 15:55       ` Clem Cole
2018-03-18 21:26   ` Tim Bradshaw
2018-03-19  0:26   ` Steve Johnson
2018-03-19 14:26     ` Warner Losh

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