Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]


Groups > comp.lang.java.programmer > #14340

Re: Teaching kids to program (in Java)

From glen herrmannsfeldt <gah@ugcs.caltech.edu>
Newsgroups comp.lang.java.programmer
Subject Re: Teaching kids to program (in Java)
Date 2012-05-06 17:10 +0000
Organization Aioe.org NNTP Server
Message-ID <jo6bau$igk$1@speranza.aioe.org> (permalink)
References (6 earlier) <tok1p7dl1cp7ipt59ilg4d0uk6jf20q07s@4ax.com> <20638428.276.1334951022461.JavaMail.geo-discussion-forums@pbcsx5> <56h3p7phgturh7hkno6k1q9pfohfdi5b6j@4ax.com> <4fa5c494$0$294$14726298@news.sunsite.dk> <jo5qec$rkl$4@localhost.localdomain>

Show all headers | View raw


Martin Gregorie <martin@address-in-sig.invalid> wrote:

(snip)
> So, back when C was specified, it made sense to have both hex and octal 
> bit representations because it was being used on both byte and word 
> oriented hardware (didn't some early DEC kit use word and character 
> lengths that were multiples of 3 rather than 4?) but now, with the 
> almost universal adoption of byte-oriented architectures there's 
> little reason, other than historic, to use octal notation.

Before VAX, everything DEC was octal. There were machines with 12
bit and 36 bit words. The PDP-11 used 16 bits, but the instruction
fields were divided up such that octal made them more readable.
Much of the PDP-11 software uses Radix 50, which is actually
base 40 because the 50 is in octal. (Three characters per word.)

With VAX, they went hex, though octal was still supported.

Stories are that DEC published a calendar with the dates in hex
in the year before VAX was released. Instruction fields are in
multiples of four bits. The DUMP commands prints ASCII and hex.
(The hex going right to left, so that little endian values can
be read correctly.)

-- glen

Back to comp.lang.java.programmer | Previous | NextPrevious in thread | Next in thread | Find similar | Unroll thread


Thread

Re: Teaching kids to program (in Java) Arne Vajhøj <arne@vajhoej.dk> - 2012-05-05 20:23 -0400
  Re: Teaching kids to program (in Java) Martin Gregorie <martin@address-in-sig.invalid> - 2012-05-06 12:22 +0000
    Re: Teaching kids to program (in Java) Arne Vajhøj <arne@vajhoej.dk> - 2012-05-06 11:36 -0400
    Re: Teaching kids to program (in Java) glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-05-06 17:10 +0000
  Re: Teaching kids to program (in Java) Gene Wirchenko <genew@ocis.net> - 2012-05-07 09:43 -0700
    Re: Teaching kids to program (in Java) Martin Gregorie <martin@address-in-sig.invalid> - 2012-05-07 18:17 +0000

csiph-web