Why aren't there external CPUs?

[Rtyh-12]

This might sound completely stupid to anyone who knows a bit of computing, but...

I was wondering, there are external hard drives, so why don't we have external CPUs? Some wired or even wireless processor that you could connect to your computer and use its processing power to speed things up. It would probably be more expensive than simply making an upgrade, but it would certainly be much easier and faster. It sounds like a very good idea, so if nobody has made it until now, there has to be some flaw in the concept.

So, why are there no external CPUs? Or maybe RAM too...:lol:

 

[Ghostrider]

"External" CPUs would mean parallel processing, and software needs to be written specifically for it.

 

[Urwumpe]

There are, but differently as you might expect. you can buy for example processor modules, that contain special purpose processors and with which you communicate by Ethernet. Those are pretty popular for image recognition.

Other than that: The further your CPU is away from I/O or memory, the slower it is. That is why the RAM on a PC is very close to the CPU in the layout, or why the next slot to the CPU is used for graphic cards.

 

[Artlav]

In the 90s Japanese made the hard drive heads with CPUs in them, that could route head movements and control related things.
That technology haven't got anywhere because nobody could think up a way on how to make this useful.

Same for external CPUs - give me an example of a task where they will be useful, or superior than a separate/networked board?

 

[Izack]

Same for external CPUs - give me an example of a task where they will be useful, or superior than a separate/networked board?

In event of cylon attack?

 

[Urwumpe]

In event of cylon attack?

In that case, Chuck Norris would be the better choice.

 

[Ghostrider]

In that case, Chuck Norris would be the better choice.

So say we all.

 

[jangofett287]

Same for external CPUs - give me an example of a task where they will be useful, or superior than a separate/networked board?

Instant scalable transportable super computer?

 

[garyw]

A lot of kit has it's own microcontrollers. hard drives have some on board logic for caching, Graphics cards have some on board logic for graphics processing and network cards have the same for optimising traffic.

As urwumpe said, the further away from all the RAM and other good stuff the CPU is the less useful it is but by having dedicated controllers for specific tasks you get the best of both worlds.

---------- Post added at 15:12 ---------- Previous post was at 15:11 ----------

Instant scalable transportable super computer?

Not really. You'd be better off with a beowulf cluster using very cheap machines but lots and lots of them.

 

[Urwumpe]

Not really. You'd be better off with a beowulf cluster using very cheap machines but lots and lots of them.

I am pretty sure, even by clustering Beagleboards, you could get more processing power.

 

[garyw]

More than likely. I believe google do something like that to increase the amount of processing power in a standard 42U rack.

 

[Urwumpe]

More than likely. I believe google do something like that to increase the amount of processing power in a standard 42U rack.

Not google, but I remember somebody lately starting commissioning a supercomputer made with ARM processors. It isn't finished, but even the TOP500 leader is still WIP.

EDIT: http://www.montblanc-project.eu/

 

[jangofett287]

If the CPU's were external. it would be a case of unplug the power, put CPU in a small case, put CPU in pocket. you could transport 100s of CPUs in a small hatchback! Then there's only the small problem of the RAM access bottleneck... I know, add external RAM as well!
I'm just being silly now aren't I?

 

[RisingFury]

IIRC, there were some PCI processors for servers...

 

[garyw]

IIRC, there were some PCI processors for servers...

You still have them - ILO cards for servers for example which are a small computer on a card to allow for remote access to a server even when the server is down but they don't add to the processing power of the server.

 

[Izack]

I know, add external RAM as well!

What you have now is a cluster, like mentioned above.

[ame="http://en.wikipedia.org/wiki/Beowulf_cluster"]Beowulf cluster - Wikipedia, the free encyclopedia[/ame]

 

[Ark]

If you made it function like an external hard drive, wouldn't it be absurdly bottlenecked by the transfer rate of USB?

 

[Quick_Nick]

If you made it function like an external hard drive, wouldn't it be absurdly bottlenecked by the transfer rate of USB?

Extremely. I was wondering what kind of performance you can get with Ethernet like Urwumpe mentioned on the last page.

 

[garyw]

Very, very poor even with 10GigE. you'd have to have a processor dedicated to working out what to offload based on the requirements of the code you are executing. If you offloaded the mathematical parts of orbiter to an external CPU, even over 10gigE you'd see major isses.

 

[Artlav]

Isn't rendering done by what is actually a special purpose external CPU?
And that GPU is linked to the system over a not-so-fast PCIE, but is still useful due to it's sheer power.