[Arm-netbook] microkernels

Luke Kenneth Casson Leighton lkcl at lkcl.net
Tue Dec 11 03:13:12 GMT 2018

crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68

On Tue, Dec 11, 2018 at 2:12 AM Christopher Havel <laserhawk64 at gmail.com> wrote:

> For example, I'm typing this on a 32bit Win7 based HP Mini netbook with an
> Atom N450 CPU and 2gb RAM. It seems to me that playing Pandora Internet
> Radio in one browser window, with another browser window of nine tabs (and
> three of those are static JPEG images retrieved from a search engine, not
> proper webpages or anything), and with the file manager having one window
> open and another image displayed in an OS-resident image viewer -- that the
> described load ought not to very nearly lock the machine up entirely. And
> yet, it does -- which, it seems to me, indicates that the gentlefolk
> they're hiring over there in Redmond these days, simply do not understand
> how to code.

 they do... they're "hampered" by some design decisions that relate to
strategically significant "convenience", at the MSRPC (more
specifically the DCOM) level.

 DCOM is a way to transparently treat remote objects as if they were
local.  however it requires that the entire function call be
serialised (marshalled) and unserialised (unmarshalled).

 for *local* systems (local procedure calls, over a transport named
"ncalrpc"), someone came up with the brilliant and simple idea of
using shared memory.  instead of doing a full serialisation, instead
the data structures would be in shared memory, at a globally-fixed

 the problem is: the *amount* of shared memory required effectively
consumes a whopping 50% of available memory.  on 32-bit systems they
subdivided the memory into 2 halves, which in turn meant that *all*
32-bit applications were hard-limited to a maximum of 2GB of physical
RAM, where the other 2GB absolutely had to be hard-reserved onto
*real* RAM.

 as you only have 2GB of RAM, and are running a modern web browser, a
massive chunk of that physical 2GB will be reserved for global
fixed-address shared memory, which in turn leaves pretty much
absolutely nothing left as far as running web browsers is concerned.

 thus, that netbook will be absolutely thrashing its nuts off, on swap-space.

 bottom line: what the f*** are you doing running windows!!



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