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What to use for browser flash support?


On 22 January 2018 at 11:21, Oliver Grawert <ogra at ubuntu.com> wrote:
> hi,
> Am Sonntag, den 21.01.2018, 23:13 +0100 schrieb Liam Proven:
>>
>> 32-bit x86 can't usefully address >3.25 GiB of RAM. There must have
>> been man-years wasted troubleshooting that. Modern OSes need more
>> than
>> that.
>
> they can... (and ubuntu carried that setup for a while in its i386
> kernel)
> https://en.wikipedia.org/wiki/Physical_Address_Extension

That specific feature is why I said "usefully".

PAE is bank-switching, as was LIM-spec EMS in the DOS era, or 8-bit
micros with >64 kB of RAM.

There's a Wikipedia article on EMS which I think I wrote most of, way back when:

https://en.wikipedia.org/wiki/Expanded_memory

Basically, the OS can page banks of RAM from above 4GB into the lower
3GB of address space. It's relatively slow. The kernel can't directly
address RAM above the 4GB line, can't run code up there, can't store
data up there. All it can do is page blocks from up there into the
space below 3GB, read/write to them, then page them back out again.

It is poor for performance, and it means that, for instance, while you
can have 3-4 apps of 1-2GB  all in RAM at once, being paged in and out
of the high memory, you can't have one app that takes >2-3GB of
memory, or which is smaller but loads a 3-4GB file.

Also, it remains a Windows world out there, and for licensing reasons,
workstation editions of Windows don't use PAE. Only server editions
can.

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