Re: [SOLVED] Is my processor 32-bit or 64-bit?
On 8/27/2012 6:12 PM, Stephen Powell wrote:
> On Mon, 27 Aug 2012 01:42:54 -0400 (EDT), Stan Hoeppner wrote:
>> Stephen Powell wrote:
>>> I know enough to be dangerous, but not
>>> always enough to be competent. That's why I opened this thread
>>> in the first place.
>>
>> In this case the solution is as simple as downloading and reading the
>> manual for your board: http://ph.academicdirect.ro/ISB_SE7500CW2.pdf
>>
>> The memory specs are on page 17.
>
> Stan, you are a wealth of information. I didn't search for the motherboard
> manual because, for some reason, I didn't think they were published online.
> Maybe I did an extensive search in the past for a motherboard or chipset
> manual and found nothing; so I already had it in my head that such things
> weren't available. But in this case I am happy to be proved wrong.
It's quite common for someone around the globe to re-host the manual for
an EOL/obsolete product. Sometimes they're easy to find, sometimes not
so easy. Your manual was pretty easy with a basic Google search. I
found it not long after this thread began.
> By the way, there's something I don't understand. A 32-bit processor can
> only access 4G of "real" (extended) memory, right? So why are there
> motherboards available for 32-bit processors that support installing
> more than 4G of RAM? What good is memory that the processor can't address?
The processor can address up to 64GB using PAE:
http://en.wikipedia.org/wiki/Physical_Address_Extension
PAE, BTW has been with us in every Intel and AMD CPU since the Pentium
Pro and K6, since 1996, 16 years, one year after I started working on
computers professionally.
All new AMD/Intel x86 CPUs for many years have had the x86-64 ISA
(instruction set architecture), so PAE is rarely used today. Before AMD
introduced the the x86-64 ISA with the Opteron, if one wanted large
memory in a server PAE was the only option in the x86 world. Only a few
systems took serious advantage of PAE, almost all for database work.
The Data General Aviion 25000 sported up to 32 Pentium Pro CPUs and 64GB
RAM, running their proprietary DG/UX SVR4 Unix variant; exclusively used
in the health care industry for patient record databases, etc. Axil
(acquired by HP) had an 8-way Pentium Pro box with up to 8 or 16GB RAM
which they sold as an MS SQL server solution. Unisys had a series of
ES7000 machines with up to 32 Xeon processors and 64GB of RAM, also sold
as an MS SQL server platform though Linux was supported. These were
really neat machines.
Somewhat off topic, but very interesting, these 32-way Unisys machines
were quite unique at the time as they could be partitioned into
independent physical servers (not virtual) of 4, 8, 12, 16, 20, 24, 28,
or 32 CPUs each. This was possible because the system was built around
4 CPU cellular multiprocessing boards interconnected by a custom cross
bar switch network which was connected to a single high bandwidth flat
memory subsystem composed of multiple interleaved channels.
It's memory bandwidth of 20GB/s was many times higher than any x86
server at that time as they all used a single P6 bus, with only 1GB/s
bandwidth. 20GB/s is peanuts today given just two channels of DDR3-1333
have just over 20GB/s, but back then, in the late 1990s, this was huge.
This CMP design also allowed assigning different amounts of memory to
each of the hosts, with the firmware and custom crossbar chipset setting
up the fences in the physical memory map. Individual PCI buses and IO
devices could be assigned to any of the partitioned servers. In the
first models, a console module had to be installed which included VGA,
KB, mouse ports and each was controlled via a KVM switch. Later models
had a much more intelligent solution in the form of a single system
controller.
This also facilitated the ability to cluster multiple sets of two
physical hosts (up to 4 clusters per server) within a single server
using system memory as the cluster interconnect, with latency thousands
of times lower and bandwidth thousands of times higher than the fastest
network interconnects at that time, this became immensely popular with
Unisys customers, many running multiple clustered MS SQL servers within
one ES7000 mainframe.
Note I used the word mainframe. All of this unique technology and
scalability Unisys brought to x86, MS Windows and, to a lesser degree,
Linux, was directly derived from Unisys' ClearPath mainframe technology,
where such features had been common for years, as well as on IBM,
Fujitsu, and other mainframes.
Sadly, due to market realities and diminished customer demand for large
monolithic servers, the biggest x86 box Unisys now sells is an 8-way 4U
Xeon box. Though with up to 80 cores, 332x times the memory bandwidth,
and similarly higher IO bus bandwidth, it runs circles around the
monster 32 socket mainframe style boxes of yesterday.
--
Stan
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