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From: tmoran@bix.com (Tom Moran)
Subject: Re: How do I get this to work??
Date: 1999/01/10
Message-ID: <36993523.2075072@news.pacbell.net>#1/1
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Newsgroups: comp.lang.ada
Date: 1999-01-10T00:00:00+00:00
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>segmentation is present in the PII, for
>compatibility purposes, and used in some limited manners in
>the operating system kernel
  How could one write such operating system kernel code with a
compiler that did not recognize the existence of segmented addresses?
(Other than using asm code.)

> Ada 95 *does* provide
>a linear address model via the Integer_Address type in
>System.Storage_Elements
  Besides the use of segments in the 8086 as a way of partially
caching memory address, and its additional use in the 286/B5500 et al
for protection and virtual memory, what about things like bank memory
architectures (eg, CDC160-A/8090 to name one)?
   What does System.Storage_Elements."-" do when the two addresses are
in different distributied partitions, potentially on different
machines?  Raise Program_Error, depending on where the partitions
happen to reside?  I hope not.

>C does NOT provide a
>linear view of the address space, so general address
>arithmetic is not possible in C
  I sure wish I had a penny for each C programmer who believes that in

  char a[10],b;
'b' is the same as a[10].  And of course the 'buffer overflow'
security holes demonstrate that is usually a correct assumption.

>assuming *you* know the 5500 architecture well
A long time ago, as an RA in the U of Wisconsin Computer Center, most
of  my job was maintaining and enhancing the OS on their B5500s.