Thread: External RAM?
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Old December 31st 17, 03:42 AM posted to microsoft.public.windowsxp.general
philo
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Default External RAM?

On 12/30/2017 07:55 PM, JT wrote:
Paul wrote:

KenK wrote:
I was wondering if I could add RAM without messing with the MB.
Google tells me that evidently you can use an external HD or thumb
drive as RAM. Is this effective? Anyone tried it? Anything better
and easy to add?

TIA


So you know there is RAM (dynamic DRAM or DRAM) inside the
computer. It's fast, and it happens to be volatile. Some day,
it's not going to be volatile any more and will remember
things even with the power off.

https://images10.newegg.com/ProductI...20-242-327-Z01
.jpg

You might notice, if you look at a bunch of motherboard pictures,
the RAM is always reasonably close to the processor itself. At
one time, the RAM connected to the Northbridge chip, and then
from the Northbridge to the CPU. But that wasn't fast enough.

So then they started connecting the RAM (RAM busses) right
on the CPU itself. Eliminate the middle man. Only inches away
from the CPU.

One reason for getting closer, is time-of-flight. Things
cannot go faster than the speed of light in the medium.
So we like to snug the RAM up, as close to the CPU as possible.

*******

OK, great, that doesn't guarantee what works, but it's
an observation none-the-less. Closer is better.

At one time, we were tight for RAM, and they had
"Extended" and "Expanded" memory. This was placed
on a card, and put in one of the expansion slots
(like a PCI slot, or hopefully, something much faster).

https://en.wikipedia.org/wiki/Expanded_memory

Now, imagine something this horrible. OK, we got memory chips
alright, and people at the time would love to own one of these.
(They would drool over stuff like this.) But the bus connection
is ISA bus.

https://en.wikipedia.org/wiki/File:E...st_4M_ISA.jpeg

And one of the ISA bus entries here is rated at 8.33MB/sec.
Well, I have one processor here that snorts info at 17000MB/sec.
That card would be a joke in practical terms.

https://en.wikipedia.org/wiki/List_of_device_bit_rates

The PCI Express bus comes close. A byte lane on PCI Express Rev3
is 985MB/sec, and we round to 1GB/sec. A x16 slot gives 16GB/sec.
Now, we're getting close to being in the ballpark. The buffer
inside the CPU, for the PCI Express bus, it uses small buffers
for PCI Express packets, and this limits the practical rate,
such that you don't get 16GB/sec. It might be as bad as 8GB/sec
in practical situations. It all depends on how "generous"
Intel is with their buffers for the packets.

But today, we don't really have extended and expanded as
part of the terminology.

*******

Now, here's one from the year 2009. But it's got a couple things
wrong with it. It benches at 215MB/sec on reads. Still too slow.
It appears to Device Manager as a disk drive.
Now, we need software, page-file-like software, if we wanted
to expand the RAM.

https://www.pcper.com/reviews/Storag...nd-running-PCI
-E-RAM-based-SSD/Packaging-Specifications

*******

If we move forward, Intel has a scheme with the word "Optane"
in it, which works as RAM.

https://www.anandtech.com/show/11208...tane-ssd-dc-p4
800x-with-3d-xpoint-memory

Typical Latency (R/W) 10µs

Now, that's slow, but they still use it for paging anyway.
Paging that isn't quite as visible to the OS.

"Intel Memory Drive Technology

Along with the DC P4800X, Intel is launching Intel Memory Drive
Technology software as a paid add-on. The Memory Drive Technology
software is a custom virtual memory system implemented as a minimal
hypervisor. The guest operating system or general-purpose
hypervisor is presented with the illusion that a portion of the 3D
XPoint memory on the Optane SSD is directly addressable, producing
an apparent memory capacity that far exceeds the capacity of the
system's installed DRAM. Under the hood and almost entirely
transparent to the guest OS, Intel Memory Drive Technology
monitors memory access patterns to cache actively used data in
DRAM and prefetch from Optane SSDs.

At a high level, this is merely duplicating the paging mechanisms
all operating systems already provide.

However, Intel claims that the heuristics used by Memory Drive
Technology can far outperform those currently used by operating
systems to manage swap space residing on storage that is far
slower than Optane SSDs.

On some workloads Intel Memory Drive Technology can offer
performance approaching that of an all-DRAM memory pool of equal
capacity, though this will depend highly on the specific
application workload.

Intel Memory Drive Technology has a substantial capacity overhead:
a 375GB Optane SSD can provide up to 320GB of virtual memory.
Multiple Optane SSDs can be used to provide virtual memory up to
ten times the system's DRAM capacity, though Intel recommends
Optane to DRAM ratios between 3:1 and 8:1. When multiple CPUs or
Optane SSDs are in use, the Memory Drive Technology software will
take into account non-uniform memory access (NUMA) effects and
attempt to optimize data placement to put data in the DRAM or
Optane SSD that is closest to the core using it.

By default, the Memory Drive Technology software will present to
the guest OS a NUMA topology equivalent to the underlying DRAM
configuration plus a pool of memory that is not local to any
of the processors, with capacity equal to the virtual memory
provided by the Optane SSDs. However, this is implemented purely
for the sake of allowing NUMA-aware software to adapt its usage
patterns; regardless of the NUMA configuration seen by the guest
software, the Memory Drive Technology software will not be
statically allocating specific address ranges to DRAM or Optane
storage.

The approach taken by the Memory Drive Technology software
allows operating systems and applications to function without
modification and without requiring Optane-specific optimizations,
but it also means there is no way for applications that are
NUMA-aware or use system calls like madvise to communicate
directly with the real memory allocator.

The full licensing cost structure for Intel Memory Drive Technology
is not clear, but the MSRP for a 375GB P4800X bundled with
Memory Drive Technology is $1951 compared to $1520 for the SSD
alone.

The Memory Drive Technology hypervisor must be booted from a
USB device or an IDE-compatible storage controller, and the
guest operating system cannot be booted in UEFI mode.

Intel Xeon E5-x6xx v2 or later and E7-x8xx v2 or later processors
are supported. [I.e. Not desktop processors]
"

So if you started with a Xeon motherboard with 64GB of real RAM,
you could install two 375GB Optane cards for $4000 and have a 64+640GB
total RAM motherboard. Speed would be on the order of 4GB/sec, and
still a bit shy of the 16GB per second I was looking for.

If the Intel Optane card was replaced with a card with DRAM on it,
like 128GB LRDIMMs or something, you could build a comparable
memory capacity, and use the Intel software to page in and out
of it. And it would smoke pretty good :-)

*******

If you walk into the Walmart today, could you buy something like
that ? $20 won't buy you a lot of hardware, and no matter what
subsystem your $20 was tied into, it would be pretty slow in
any case.

I believe there probably are whizzy setups in HPC labs around
the world, that we don't hear about. For example, you can join
PCI Express busses together like Lego and build bigger things.
The PCI Express bus can be extended outside the PC box,
and the Bitcoin miners show an example. These allow gadgets
like video cards, to run outside the PC. We don't get to
see too many pictures of lashups with these, but at least
it shows one of the form-factors out there.

http://cryptomining-blog.com/tag/pci-express-extender/

*******

If you're not mobile, it's possible an organization like Geek
Squad makes house calls. Maybe you could get them to add RAM
on-site.

Many older motherboards, simply don't have the space for
extensive quantities of additional RAM. Maybe the old RAM
has to be removed, to make room for a larger set. Or if you
want larger expansion options, it's a new motherboard.

I have an S370 motherboard with 1.5GB of RAM.

I have an Asrock 4Core board which only held a
max of 2GB of DDR2 RAM. And that one, I had a Core2
processor in it (2.6GHz). That makes a fine WinXP board.

My typing machine is an X48 based motherboard, and
holds 8GB of DDR2. 3.1GB of that is available in WinXP x32,
and 4GB is used as a RAM Drive. The excess RAM is not
wasted, but works like a disk drive.

https://s17.postimg.org/o3q61a3u7/RAMdrives.gif

That's what happens when you have too much RAM.

WinXP x32 doesn't really go over 3.1GB for your copy of Firefox.

And when you buy items like this, you'll never have
to complain about running out of RAM slots. This one
has room for 32 DIMMs. At $200 for a relatively cheap
DIMM, it takes $6400 just to fill the slots with something
and make it look pretty :-) The CPUs range from $750 to $2100
or so for the various versions. To run WinXP on this, requires
using the cheaper CPUs, because the $2100 ones have too
many cores for WinXP Pro :-)

https://www.supermicro.com/Aplus/mot.../H11DSU-iN.cfm

And at 17" x 17", it won't fit in your computer case,
and will be easy to reach for RAM upgrades :-) I'm
sure Stephen Hawking wants one of those (he was given
a computer with a 1TB or 2TB limit a number of years
ago, and theoretically that board could top it).

*******

If you want to get some idea of what options you have,
take a look at the machine using CPUZ. You won't have to
open it up, but you'll get some identifiers about what
is inside the box.

https://www.cpuid.com/softwares/cpu-z.html

Zip English 32 or 64-bit version

This is the info that is useful for someone picking
out an upgrade for you. If I sent this to Geek Squad,
I would expect the staff to decode this and give me
a price and options. Or, if you provide the info here,
I can take a crack at it.

https://s17.postimg.org/8c07b8u6n/I_...send_email_to_
Geek_Squad.gif

It takes time to test RAM after it is installed, but
the time to plug in the DIMMs shouldn't take more than
ten minutes with an anti-static strap. For devices like
tablets with the RAM soldered down, you can't upgrade
those. The above info is mainly for the "easy" cases
like desktop computers. Even some laptops have "half"
the RAM soldered down. CPUZ cannot tell you where they
have dribbled solder and made upgrades impossible.

Paul


Paul, you reminded me of the old AST "Six Pack"

It was one of those LIM (Lotus Intel Microsoft) EMS boards.

http://www.retrocomputing.net/parts/...0080sixpak.JPG

You had to manually insert 9 chips in each bank,

9th chip was for parity. I remember begging my manager for

a few extra chips as it was VERY easy to bend pins on those

"DIP" chips!!!

Wow! How time flies!

Do you remember the old debug command" G=C800:5 (for WD)??

I'm getting old!

JT




LOL:


I do recall the debug command


BTW: Speaking of adding RAM, I still have my Zenith Data Systems 286

It came with 512k of on-board RAM


At some point I was given an ISA memory expansion board and just as an
exercise installed 16 megs or RAM...the maximum a 286 can address.

Had 16 megs of RAM been available at the time the 286 was manufactured,
it would have cost a fortune.
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