Lies in education [was Re: The "loop and a half"]

[Chris Angelico]

On Sat, Oct 14, 2017 at 6:32 AM, Peter J. Holzer <hjp-usenet3 at hjp.at> wrote:
> On 2017-10-13 14:51, Chris Angelico <rosuav at gmail.com> wrote:
>> On Sat, Oct 14, 2017 at 1:32 AM, Steve D'Aprano
>><steve+python at pearwood.info> wrote:
>>> It seems to me that you're not talking about ROM at all, but ordinary RAM.
>>> Then what do you mean by "read only"? A block of memory with a flag that
>>> says "unprivileged processes are prohibited from writing here"?
>>>
>>> (That's also not a rhetorical question.)
>>
>> When I first learned about Protected Mode (as defined by the Intel
>> 80386 and used in OS/2), there was a real concept of read-only RAM.
>> The program loader would fetch up the executable file (data on the
>> disk) and construct its segments: code, data, and BSS/stack.
>
> This is still the case. The granularity is just finer now: Instead of
> segments you use pages. (The 386 was the first x86 processor which
> supported paging. OS/2 probably used segments because it was originally
> designed for the 286.)

... either that, or I'm just misremembering, it being many MANY years
since I did anything that low-level. Let's assume I was mistaken. :)

ChrisA