Thank you David. I remember the 286 and 386 machines and Windows 3.1 My how far we have come!!!
Between all of you I think I have the information I need. Bottom line, I will have to find other programs but it looks like my printers will be okay.
tannis z TN
--- On Thu, 10/29/09, David Gillett <[log in to unmask]> wrote:
> From: David Gillett <[log in to unmask]>
> Subject: Re: [PCBUILD] Dell Studio 17
> To: [log in to unmask]
> Date: Thursday, October 29, 2009, 6:27 PM
> On 26 Oct 2009 at 19:37, Dean Kukral
> wrote:
>
> > There is a little confusion here that I think that I
> can clear up. A
> > 64 bit system - "a 64 bit architecture" - refers to
> the word length
> > internal to the cpu. It generally represents the
> number of memory
> > locations that can be addressed in one word, two to
> the sixty-fourth
> > power. I believe that all home computer cpu's
> have had a 64 bit
> > architecture for a good number of years.
>
> There are actually THREE numbers of interest here:
>
> 1. The size of integer data registers in the
> CPU. When people
> talk about a given CPU as being "X bit", this is almost
> always
> the number they are actually referring to. This is
> still 32
> bits for most Intel and compatible processors unless they
> are
> designated "64 bit" which, although becoming more and more
>
> common, is still a minority.
>
> 2. The size of address registers in the CPU.
> This used to
> commonly exceed the size of the integer data
> registers: most 8-
> bit CPUs used 16-bit addresses and the 16-bit PC CPUs (8086
>
> through 80286) used 24-bit addresses. 32-bit data
> registers
> with 32-bit addressing has kind of been a sweet spot for
> almost
> 20 years.
>
> 3. The width of the physical memory address bus
> (collection of
> pins) on the CPU, which is almost never wider than the
> address
> register size. This determines the actual maximum
> addressable
> physical memory. For instance, the 80386 SX and DX
> processors
> both used 32-bit address registers, but the SX had only 24
>
> physical address pins, limiting it to 16MB of physical RAM
> (but
> making it easy to adapt tp motherboard designs intended for
>
> 80286 CPUs...).
>
> Windows 3.x was a 16-bit OS. Most of the
> machines that ever
> ran it had 32-bit CPUs (80386 or better), and a popular
> optimization trick was to use the 32-bit data registers
> (which
> required at least an 80386) for arithmetic while sticking
> with
> the 24-bit address architecture from the 80286. The
> Pentium Pro
> CPU had an optimized 32-bit core, but it's 16-bit subsystem
>
> lacked performance and so it did poorly with Windows
> customers.
> Intel corrected that in the Pentium II, and Microsoft
> finally
> released Windows 95 and NT 4,
> Now we have CPUs available which provide 64-bit data
> and
> address registers, and since XP Microsoft has been shipping
> OS
> versions which support and take advantage of those. A
> 64-bit OS
> version won't run on a CPU that isn't also 64-bit. A
> 64-bit OS
> knows how to manage RAM that could have physical addresses
>
> bigger than 32 bits, so is a prerequisite for systems using
> more
> than 4GB of total address space. (But the only 64-bit
> CPU I
> currently own is on a motherboard that is limited to 2GB of
> RAM,
> so CPU and OS support while required is not sufficient.)
>
> Windows 95 was able to support 16-bit applications
> by running
> them in one or more virtual 16-bit environments, and the
> 64-bit
> versions of Windows are able to do similar (better,
> actually)
> for 32-bit applications which are still the vast
> majority. That
> trick doesn't really work for the OS itself, though, or for
>
> drivers which need to act as OS components. If you
> are buying
> or building a new system out of pretty standard components,
> that
> shouldn't be an issue, but if you need to support some
> oddball
> or legacy peripherals, lack of 64-bit driver support may
> rule
> out a 64-bit OS version. But you may still find the
> price/speed
> of a 64-bit CPU and matching motherboard competitive with
> 32-bit
> versions, and the 32-bit OS and drivers etc will work on
> them
> just fine.
>
> David Gillett
>
>
> Do you want to
> signoff PCBUILD or just change to
>
> Digest mode - visit our web site:
>
> http://freepctech.com/pcbuild.shtml
>
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