This is the type of things we discuss in betas
Eric,
Thanks, and I am glad you enjoyed it. I am not educating you here, just
talking on into a bright sun to tan my brain and ward off the grimy reaper.
It is the "what" vs. the "why". Once one understands the fundamentals then
you have a universal that applies to all chips that address things and
underlies the language of people in the various disciplines that talk about
accessing memory. The differnence between a fundamental and systems
organizations create the variety of responses.
When one speaks of an OS the systems language definitions they hold before
their mind changes everything. How much memory can a 32 bit OS address????
Directly or otherwise? With virtual memory and unlimited time a 4 bit
machine can address as much memory as a 64 bit machine can. Using sky
computers, the internet, and grated permissions again with unlimited time I
can address the entire world. The implicit assumptions in the answer changes
everything.
If you consider a 32 bit OS, then you can directly address 4GB and that is
for the definition that the drivers are part of the OS which they are. If
one means what can a user address with a user mode program, then the amount
will be very much less. So the viewpoints all vary according to people's
definitions and there were no wrong answers given. If one assumes hardware
can swap blocks of offshore memory in and out of an address space, then one
might answer a large number while one who speaks of the wires coming out of
the CPU will say 4GB regardless of what it is or isn't connected to. A
processor can produce addresses even if memory is not connected. Is it a
memory address 
.
So when people answer, one looks at the context of that answer (what
discipline the person is in, or where he/she is coming from), and one
understands and agrees within that context even though all answers are
variants.
The fundamental remains a constant across the spectrum so no matter where
you are and what you are doing you will not be lost as long as you learn the
abc's.
I tend to answer the "why", and not the "what", it is the give a man a fish
and feed him for a day vs. a lifetime attitude. The "why" makes one's
knowledge independent of the process, the mother board, and the various
plug-ins. The "why" also allows one to become and inventor by devising other
kinds of "whats".
I had a nephew that used to drive me up a wall with questions that he did
not want to understand, he wanted absolute answers and expected everyone
around him to be an enclosed for his personal use. He was either too lazy to
think, or had not yet experienced the joy of self discovery. He has grown
into an engineer and is employed so I suspect he is thinking on his own now
.
The presentation I gave was low enough that many hungry "young", people will
understand it immediately and hopefully may create excitement within. We old
people rely on young people pretending we know everything so we can remain
fixtures rather than discoverers. I don't write to the people who's
knowledge is established; of what use can I be to them? If a person scared
of computers buried under billions of damn marketing acronyms grasp the
fundamentals then that person is fundamentally changed and may learn that
he/she can learn it all too just like the rest of us pretenders:). That
person will forge the next generation while those of us who memorize
acronyms will stay fat and happy where we are. I don't wish to judge even
though judging brings great joy. All types of people are required to make
the world go around. Without the person that finds joy in getting his/her
hands dirty building and testing the hardware the bright abstract engineer
is bound to failure; they need each other and there are just so many hours
in a lifetime. I always treated the people who emptied my waste basket as
engineers for where would I have been without them? My job was such leisure
by comparison. They made it possible for others to build a better world (and
as WWII taught us, build a more evil world as well. Innovation has no
morals.).
Paul
"Eric A. Whalley" <ewhalley@telus.net> wrote in message
news:stq4s4d4jvfas4vgcvv2lmd5ei8sfn94pu@4ax.com...
> Paul
> Now this is what I love . School is in you are giving the lecture
> on architecture limits . Using math to explain chip proccessing
> limits. Was at a conference ten years ago where they discussed board
> design and how it had reached its limits then .You know the old road
> blocks bus ,cpu.ram and hard drive .At that time they talked of
> radical change to allow the board to access direct paths to
> hardware etc .HMMPH nothing and I repeat nothing has changed . Same
> board architure after twenty five years !
> Certainly ram has increased . eight megs wow what a rocket .The new
> solid state drives hot diggity dam .YAHHH wonderful . Same stupid road
> blocks .
> Getting off my pedastal now . My little pet rant .
> Eric A. Whalley
> " <proussin@> wrote:
>
>>For 32 bit computer chips, the number of address wires going out to select
>>data in memory is 32 wires. People tend to call it 32 bits.
>>
>>Any of those 32 wires can have a voltage on them or zero volts on them. If
>>there is a voltage on a wire people say that wire is on, or the bit is on,
>>or the bit is set etc.
>>
>>The custom is to simply say a set bit has a value of 1, while a reset or a
>>clear bit has a value of 0. Note 1 and 0 are just names. That is just for
>>discussion, the actual voltage doesn't matter as long as you can tell if
>>the
>>bit is set or clear. Note that if a single wire can be on or off then it
>>can
>>sit in two states. One wire, orone bit can be in one of two states, 0 or
>>1.
>>I won't mention the fact that you could have many more states on a wire,
>>because the complicates things and the reliability to have multistate
>>computers is expensive. We will sitck with 0 and 1 also called boolean
>>values.
>>
>>How many distinct states can a group of wires represent. Let us play a
>>game
>>and figure it out.
>>
>>Say you have one wire and build what is called a state table.
>>
>>By definition of the problem, the wire can have two settings, 0 or 1 and
>>the
>>table looks like this.
>>w
>>0
>>1
>> It is a single column. This single wire can represent two values. If you
>>are addressing memory then it can represent two addresses.
>>
>>Let us try two wires and each wire can be independently set on or off.
>>Just
>>for fun let us call the two wires w and x. Like in decimal w is to the
>>left
>>and we say it is more significant.
>>wx
>>00
>>01
>>10
>>11
>>Note that we now have 4 distinct patterns. So 1 wire gives 2, and 2 wire
>>gives 4.
>>Note that 00 is counted as a pattern. You can give those patterns a value
>>like 0,1,2, or 3. You don't have to give the pattern those values, but
>>then
>>you are in your own encrypted world and no one can talk to you.
>>
>>Let us try 3 wires wxy and build a table for that.
>>Note this produces 8 distinct patterns so you can address sets of unique
>>data for memory.
>>wxy
>>000
>>001
>>010
>>011
>>100
>>101
>>110
>>111
>>This can represent 0 through 7.
>>
>>What have we figured out so far???
>>1 wire produces 2 patterns,
>>2 wire produces 4 patterns,
>>3 wire produces 8 patterns,
>>
>>Note that 1 raised to the power of 2 is 1,
>>Note that 2 raised to the power of 2 is 4,
>>Note that 3 raised to the power of 2 is 8.
>>
>>Hmmm, there appears to be a simple formula that we can use.
>>If we have 4 wires we should address 16 memory locations????
>>Try it:
>>wxyz
>>0000
>>0001
>>0010
>>0011
>>0100
>>0101
>>0110
>>0111
>>1000
>>1001
>>1010
>>1011
>>1100
>>1101
>>1110
>>1111
>>
>>Yes we have 16 unique patterns.
>>Every time we add a wire we double the previous capability.
>>
>>8 bits is 2^8 (2 raised to the eight power) or 256.
>>16 bits can address 65536 unique addresses.
>>32 bits can address 4GB or 4294967296 bytes.
>>
>>Since a 32 bit operating system can't add wires then it can't address more
>>than 4GB.
>>
>>There are tricks you can play but they involve extra hardware and there is
>>a
>>setup involved. You can address bytes over the network for example, but
>>now
>>the access is terribly slow. You can add hardware to your computer but
>>again
>>there is setup overhead. There are a few schemes for this.
>>
>>So with 32 bits you can directly address 4GB without any overhead, and you
>>since you can set the address bit pattern as you please you can read
>>memory
>>at random addresses.
>>
>>So direct memory addresses space is (Number of wires)^2.
>>
>>Some memory is reserved to talk to the video card, so the video card can
>>share that memory with the CPU. This lets you read and write directly to
>>and
>>from a picture although modern computers have made this much different and
>>you have to use system services these days.
>>
>> Other pieces of hardware also use shared memory so a 32 bit OS will give
>>your programs 4GB, but quite a it less.
>>
>>Now to the latest chips: 64 bits = 2^64 and that is mighty big!
>>
>>If you started counting on Monday you would finish counting the same day
>>from exhaustion.
>>
>>Paul
>>
>>
>>
>>
>>
>>
>>
>>"paul reed" <gifted_id2@hotmail.com> wrote in message
>>news:%23Myky5CqJHA.1452@Baybnewsweb03.SND.RNO.GBL...
>>> Well, I guess I could find this out with some diligent research,
>>>
>>> but I'm not in a rush for the answer, so I'll post it here.
>>>
>>> I say again, is there still a 4g memory limit on the 32 bit
>>> flavor of Windows 7?
>>>
>>> And, I guess the next question would be, if so, why?
>>>
>>> thankx,
>>>
>>> paul r.
>>>
>>> : ))
>>>
>>>
