Re: memory reading and writing

From: Gyps (gyps_rueppelli_at_yahoo.com)
Date: 07/18/04 

Date: 18 Jul 2004 02:23:30 -0700

"Beth" <BethStone21@hotmail.NOSPICEDHAM.com> wrote in message news:<bkfKc.503$eS1.28@newsfe4-gui.ntli.net>...
> ..._with_ caches, your system is a 850MHz Celeron...with them
> disabled, it effectively might as well be a 133Mhz Celeron
> (well, maybe more like 150Mhz or something...as, of course, not
> all instructions access memory and those will return to
> operating at 850MHz...quite a "st-st-st-stutter" the machine's
> got there without the caches, eh? ;)...

We all seem to throw out frequencies, but how does, say, 133Mhz
actually translate into time for a single memory access??

I heard somewhere that the access speed for typical RAM are
around 70 nanoseconds...but, as you say, there are so many
specialised devices and complicating factors, it's probably
not accurate to determine the access speed by doing some simple
math...

> Consider something like a 3GHz machine with only a 200Mhz bus or
> whatever...makes quite a bit of difference...which is why we
> notice that there's a kind of "trend" towards taking things away
> from the CPU and distributing the processing around...

Yes, nowadays, simple microprocessing chips are a common part of
most peripheral devices like disk-drives, VGA, modems etc.

Distributing processing among several devices with each having
an appropriate 'built-in' memory and micro-controller is a neat
concept and quite essential for 'performance' under modern OSes
and 'multi-gigabyte' games and videos.

> It's really the "Achilles Heel" of modern PCs that, between
> components, there's such a "bottleneck"...of course, as we're
> seeing here, there's all manner of "tricks" used to get around
> it...but this is a central issue to do with performance that
> both hardware and software developers need to consider...after
> all, something like developing a 5GHz CPU sounds impressive but
> can anything else in the system keep up with it? Currently,
> no...not even close usually...rather the CPU tends to do a whole
> bunch of stuff in "batch" (with the L1 cache), so to speak, and
> then it gets "flushed" to the rest of the system at a more
> reasonable pace for the rest of the system to deal with...

Interesting, if the object itself is small enough, highly
expensive materials and engineering techniques can be brought to
bear, and the 'component' made 'high-performance', but when it
comes to such a, relatively, 'large' and 'spread-out' component as
the parent-board, then those same techniques become prohibitively
expensive.

> The one thing I don't particularly like about this kind of thing
> is that, until recently, all the stuff that was moved off the
> CPU onto the hardware wasn't quite as programmable as it should
> be...the new "shader" stuff on video cards is trying to rectify
> it a little, where you actually send it a kind of set of
> "assembly language" instructions...but, well, if this stuff is
> going to be necessarily moved "off-CPU" then it would still be
> nice if it was all still perfectly programmable...

Yes, this is a basic 'conflict' between hardware engineers and
software developers. Making the hardware more programmable
would be good from the point of view of flexibility, software
performance etc., but, the implementing the necessary 'logic'
circuits becomes more and more comlplex for the hardware engineers.

Thats, one of the reasons why, specialised microprocessors for
peripheral devices have become the norm, the amount of cicuitry
needed to control the actual, complex device on the one hand and
on the other hand to present a clean, yet programmable and
standards compliant interface to the software is complex enough
to warrant the use of small, specialised microprocessors.

> ...and, if you've got
> the money to afford it, they could install superconductors
> rather than semi-conductors to eradicate all
> resistance...unfortunately, there aren't any "room temperature
> superconductors" yet - one of the mythical goals like "Cold
> Fusion" that scientists chase after -
Actually, I think I read somewhere recently that recently methods
have been found to develop materials with super-conducting
properties well above room temprature...I think this is the link:

http://www.globaltechnoscan.com/5thDec-11thDec01/superconductors.htm

> It's actually interesting to see how the technology effects
> things...

Yes, even more interesting to speculate how it might affect
things hence...

> With the old Commodore 64 machines,...

Well, effectively, my first tryst with the 'PC' was an old
8086 box, with, I believe, Minix, at my school. Later on,
in university, I got to try my hand at BSD and Linux.
Nowadays, it mainly shuffling back-and-forth between Win98/WinXP
on the one hand and Linux (Slackware) on the other hand.

It's fascinating though, to hear from 'old hands' like you,
about the evolution of PCs ;)

> Which is actually another argument against some of the "fixed
> thinking" that often emerges because a technological change can
> often completely redefine what's "normal" that things change all
> around again...because, for instance, the software now typically
> on mobile phones and palmtops are the old style of software that
> could be feasibly written by lone developers as a "hobby"
> (indeed, lots of the software for these things are quite
> literally "ports" of old games and things that used to be on the
> older "home micro" machines :) and not actually require "teams"
> and big "projects" and Hollywood budgets to develop them...the
> resurrection of the "bedroom / garage programmer" (which is what
> Bill Gates started out as ;), who'd been declared "obselete" at
> one point...they also have limitations on speed and size where
> assembly language coding can make an important impact...

Yes, it's quite essential that programming, as defined for most
small to medium tasks, remains attractive and 'doable' to single
users with no great 'resources' or 'expertise'.

The 'open-source movement' of the 90s has demonstrated that
software projects that were considered feasible only by large
'corporations' *can* be done in a collectively and 'ad-hoc' yet
very effective manner.

We need to keep alive 'alternative' methods for various reasons
but primarily because, 'corporations', notably MS, have time and
again proved that they care ONLY about 'next-quater' profits
and to please a few rich 'customers' with bloated software that
the latter, ignorantly, think is 'innovative' and 'efficient'.

The greatest threat currently, is the so-called 'trusted computing'
effort by MS along with other big names like Intel, IBM, Dell etc.
The technology aims at 'authenticating' and 'verifying', with the
help of specialised cryptographic hardware chips, ALL the programs,
documents, files and even your hardware 'configuration', AND,
reporting all this data to certain central servers to 'verify' if
the source can be 'trusted', and, if not, stopping the computer and
forcing you to 'acquire' a new 'license'.

Such a scheme, if fully implemented, (and granted it does seem to
be facing a lot of 'implementation' and 'engineering' challenges),
would place ALL the activity of all participating computers, at
the sole mercy of certain 'corporate-controlled', 'big-business'
dominated servers. Even opening a document file on your hard-disk
would first have to be 'authorised' by communicating with such a
server, if reports are anything to go by.

And, those computers which chose to stay away from installing
the special chips and software, in other words, choosing not to
come under the auspices of 'Palladium', will become totally
alienated, and incompatible with most mainstream networks and
computers. Of course 'big-business' will switch over to 'Palladium'
gleefully, at the first glance from Mr.Bill...so, pressure to
'comply' will mount ever-increasingly on 'Non-Palladium' computers.

The 'idea' of course is to 'mega-centralize' everything. This
appeals strongly to most goverments, especially USA, and most
big to medium businesses. It's the end-users, especially those
of us who are a bit more 'freedom-loving' than others who will
be hit hard.

All sorts of excuses have been given for this Orwellian scheme,
like music piracy, terrorism and all such utter crap. But to me
the scheme itself seems to be a bigger 'long-term' threat than
a few illegal music files...

And, this is only a small fraction of the 'issues' facing the
world of computers alone...I haven't even started on other issues
like environment etc. etc.

However, since I am not Beth, I will stop here and allow her to
take over... ;)

> One thing I have found interesting over the years is that the
> "ubiquitous computing" idea is really having trouble getting
> ground...it's the old "sci-fi" idea of technology that's so
> "integrated" into things that you're not really noticing
> them...there's been many attempts but it never quite "clicks"
> with people...I'm beginning to wonder if this one of those
> psychological things...like the idea of eating pills for food -
> even if made technological possible - probably wouldn't actually
> fly in practice because, well, people often _ENJOY_ cooking and
> eating...people actually like their computers to have a "face"
> and a "place" (a "computer room" :)

Indeed, I am one of those persons who doesn't really like
computers being embedded in every little thing for the most
trivial of purposes.

Computers should only be used in situations where their absence
would create significant decrease in 'productivity' and in errors
leading to loss of life etc. etc...

But, embedding a micro-processor in every little thing isn't
to my personal liking. I like to spend a portion of my day
programming, checking mail, looking up things on the net, but,
having done that, I like to completely shut down the PC and
focus my attention on other matters.

Although I am quite interested in cs, physics etc, I made a
few foolish 'slip-ups' in my earlier education which has
prevented me from actually taking up computer science for
further studies. So, actually now I am doing ecology instead,
but, to be frank, I have always liked biology as well, so, I
am doing *something* that interests me, though I often regret
that I couldn't avoid making those mistakes so that my options
could have been broader...
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