🚀 go-pugleaf

In article <458mrk$enl@inferno.mpx.com.au>, msmith@jolt.mpx.com.au says...
>
>It sounds as though everyone is agreeing with each other.  We can't have 
>that in this news group.  Allow me to supply an opposing point of view.
>
>There are two reasons for increasing your bus size.
>        1.  To address more memory
>        2.  To increase throughput (bandwidth).
>
>Very few people (who I know anyway) buy 64 bit machines to address more 
>than 4GB of memory.  They do it to get faster throughput.  The extra 
>address space is simply a side-effect.  While increasing your bus from 32 
>to 64 bits may increase your address space by an enormous amount, it only 
>increases the throughput by a factor of 2.  I can easily imagine users 
>(in the next few years) wanting 128 bit graphics cards, disk controllers 
>and network interface cards and thus wanting a 128 bit bus.
>
>There!  That should start an argument.
Yes.  You are 100% wrong.  The width of the data bus has nothing to do with
the amount of memory you can address.  There are computers today with 128 bit
wide data busses, very high memory bandwidth and a limit of 4Gbytes of total
memory.

There are at least 4 places where people talk about an n-bit computer:
 (1) How many bits of linear address space are available to a single
     instruction?
 (2) How many bits of physical address space are available to the operating
     system?
 (3) How many bits get added in an integer add instruction?
 (4) How many bits get transmitted over the system bus on a cache miss?
All of these numbers can (and mostly are) different.  You are confusing (1) 
and (4).
--
--------------------------------------------------------------------
Donald A. Lewine                (508) 898-6488 Voice 
Data General Corporation        (508) 366-0750 FAX
4400 Computer Drive. MS D112A
Westboro, MA 01580  U.S.A.
Internet: Don_Lewine@dg.com -or-
          dlewine@cheshirecat.webo.dg.com
The user assumes the entire risk as to the accuracy and the use
of this document.