The Straight Dope

Go Back   Straight Dope Message Board > Main > General Questions

Reply
 
Thread Tools Display Modes
  #1  
Old 04-11-2011, 02:29 PM
MaxTheVool MaxTheVool is offline
Member
 
Join Date: Aug 2000
Location: Santa Clara, CA
Posts: 9,216
Current iPhone vs past supercomputers

I just got a new iPhone. How far back in time would I have to travel for it to be the most powerful computer in the world?
Reply With Quote
Advertisements  
  #2  
Old 04-11-2011, 02:59 PM
engineer_comp_geek engineer_comp_geek is online now
Robot Mod in Beta Testing
Moderator
 
Join Date: Mar 2001
Location: Pennsylvania
Posts: 8,908
Somewhere around the late 60s to early 70s.
Reply With Quote
  #3  
Old 04-11-2011, 03:37 PM
sevenwood sevenwood is offline
Guest
 
Join Date: Aug 2003
As an example:

in 1976, Cray Research unveiled the Cray-1, an unbelievably fast computer designed specifically for scientific computing. It had a theoretical performance of 160 MIPS. It contained roughly 8Mbytes of main memory, weighed 5.5 tons (including its freon refrigeration system), consumed 115Kw of electricity, cost 5.5 million dollars, came with no apps (other than a FORTRAN compiler), and couldn't make phone calls.

Last edited by sevenwood; 04-11-2011 at 03:39 PM..
Reply With Quote
  #4  
Old 04-11-2011, 03:39 PM
Giles Giles is offline
Charter Member
 
Join Date: Apr 2004
Location: Newcastle NSW
Posts: 12,010
Quote:
Originally Posted by sevenwood View Post
... and couldn't make phone calls.
But could it take photographs and let you browse the Web?
Reply With Quote
  #5  
Old 04-11-2011, 03:42 PM
Whack-a-Mole Whack-a-Mole is offline
Guest
 
Join Date: Apr 2000
The CDC-7600 was built in 1969 and a a peak performance of about 36 MFLOPS which is about the same as the iPhone 4.

That machine cost $5 million in 1969 which is $29.4 million in today's dollars. Rather bigger too.
Reply With Quote
  #6  
Old 04-11-2011, 04:15 PM
Ravenman Ravenman is offline
Charter Member
 
Join Date: Jan 2003
Location: Washington, DC
Posts: 14,621
Quote:
Originally Posted by Whack-a-Mole View Post
That machine cost $5 million in 1969 which is $29.4 million in today's dollars. Rather bigger too.
Does that price include the white belt and orange shirt?
Reply With Quote
  #7  
Old 04-11-2011, 04:51 PM
t-bonham@scc.net t-bonham@scc.net is offline
Guest
 
Join Date: Mar 2003
Quote:
Originally Posted by Ravenman View Post
Does that price include the white belt and orange shirt?
That was out in California, so what do you expect?

Back in Minnesota, where those machines were designed & built, they wore plaid flannel shirts.
Reply With Quote
  #8  
Old 04-11-2011, 09:12 PM
Keeve Keeve is offline
Guest
 
Join Date: Aug 2000
First you have to define what you mean by "powerful". One way is by getting an engineer to measure how fast the internal electrons are talking to each other. But if you mean in terms of how much it can accomplish visibly to an ordinary person, I'm guessing that you'd have to go back to before Thomas Edison.

I'm being serious. Beside its usefulness as a flashlight, how much can an iPhone do when there's no network to connect to? One of the reasons I'm staying away from the current generation of smartphones is that all their smarts vanishes when the Cloud is out of reach. Specifically, I was looking for a phone/PDA that would let me edit simple text files and save them on the device (rather than in the cloud), and I couldn't find any. Can one even use camera, or are those saved in the cloud too?

I suppose I must admit that I'm exaggerating. I think they have calculators that can be used. I guess that brings it to the early 1970s.
Reply With Quote
  #9  
Old 04-11-2011, 09:17 PM
Shmendrik Shmendrik is offline
Guest
 
Join Date: Nov 2007
Quote:
Originally Posted by Keeve View Post
First you have to define what you mean by "powerful". One way is by getting an engineer to measure how fast the internal electrons are talking to each other. But if you mean in terms of how much it can accomplish visibly to an ordinary person, I'm guessing that you'd have to go back to before Thomas Edison.

I'm being serious. Beside its usefulness as a flashlight, how much can an iPhone do when there's no network to connect to? One of the reasons I'm staying away from the current generation of smartphones is that all their smarts vanishes when the Cloud is out of reach. Specifically, I was looking for a phone/PDA that would let me edit simple text files and save them on the device (rather than in the cloud), and I couldn't find any. Can one even use camera, or are those saved in the cloud too?

I suppose I must admit that I'm exaggerating. I think they have calculators that can be used. I guess that brings it to the early 1970s.
I don't know of any smartphone which can't edit and save files locally. Depending what apps you have installed, your iphone/android/windows phone can do a heck of a lot of things with no network.
Reply With Quote
  #10  
Old 04-11-2011, 09:26 PM
Shagnasty Shagnasty is offline
Charter Member
 
Join Date: May 2000
Posts: 22,525
Quote:
Originally Posted by Shmendrik View Post
I don't know of any smartphone which can't edit and save files locally. Depending what apps you have installed, your iphone/android/windows phone can do a heck of a lot of things with no network.
Like play media files and even edit them. You have to go to the fairly recent past to get that. I don't think an early Cray could do much with any media file without the software to go with it which is another huge part of this question.
Reply With Quote
  #11  
Old 04-11-2011, 11:06 PM
pulykamell pulykamell is offline
Charter Member
 
Join Date: May 2000
Location: SW Side, Chicago
Posts: 31,141
Quote:
Originally Posted by Keeve View Post
Beside its usefulness as a flashlight, how much can an iPhone do when there's no network to connect to?
Pretty much anything except surf the web, get email, and make phone calls. Like any other smart phone. What gave you the impression you needed the cloud to do anything useful on the phone?
Reply With Quote
  #12  
Old 04-11-2011, 11:14 PM
Todderbob Todderbob is offline
Guest
 
Join Date: Dec 2008
Quote:
Originally Posted by Keeve View Post
First you have to define what you mean by "powerful". One way is by getting an engineer to measure how fast the internal electrons are talking to each other. But if you mean in terms of how much it can accomplish visibly to an ordinary person, I'm guessing that you'd have to go back to before Thomas Edison.

I'm being serious. Beside its usefulness as a flashlight, how much can an iPhone do when there's no network to connect to? One of the reasons I'm staying away from the current generation of smartphones is that all their smarts vanishes when the Cloud is out of reach. Specifically, I was looking for a phone/PDA that would let me edit simple text files and save them on the device (rather than in the cloud), and I couldn't find any. Can one even use camera, or are those saved in the cloud too?

I suppose I must admit that I'm exaggerating. I think they have calculators that can be used. I guess that brings it to the early 1970s.
You should take another look at smart phones, the abilities you describe have been around since Windows 6.0, at least. And that well predates 'modern' smart phones (like Android and iOS based devices).

Last edited by Todderbob; 04-11-2011 at 11:14 PM..
Reply With Quote
  #13  
Old 04-11-2011, 11:24 PM
Terry Kennedy Terry Kennedy is offline
Guest
 
Join Date: Nov 2009
Quote:
Originally Posted by Shagnasty View Post
Like play media files and even edit them. You have to go to the fairly recent past to get that. I don't think an early Cray could do much with any media file without the software to go with it which is another huge part of this question.
Music synthesis on the PDP-1, 1964 Link.

In the late 70's I was fooling around at a recording studio and used an S-100 computer to digitize, store, and play back audio. This was with 8-bit sampling at a low (several KHz) rate. That was well before there were CDs - the basic format was probably defined at the time I did my audio work, but the availability of audio CDs was several years away.

The main limitation was the cost of storage (both main memory and disk) - in the mid to late 70's disk drives that stored anywhere from 5MB to 200MB were the size of washing machines and very expensive. A typical hobby computer had somewhere between 8KB and 64KB of main memory and (if a high-end system) perhaps 512KB of disk (a pair of single-density 8" floppies).
Reply With Quote
  #14  
Old 04-11-2011, 11:29 PM
thirdname thirdname is offline
Guest
 
Join Date: Mar 2005
I'm surprised an iPhone has so little power. I thought it was like a little computer. I know it has less power than a computer, but I thought it would at least have a tenth the power of a current desktop. Isn't 36 MFLOPS like, a hundredth or a thousandth of a modern desktop, or am I wrong?

I googled attempting to find out the FLOPS of an iMac and ended up on this page: http://www.intel.com/support/process.../cs-023143.htm that lists Intel processors in the tens of GFLOPS.
Reply With Quote
  #15  
Old 04-11-2011, 11:36 PM
Uncertain Uncertain is offline
Guest
 
Join Date: Oct 2007
Quote:
Originally Posted by Keeve View Post
First you have to define what you mean by "powerful". One way is by getting an engineer to measure how fast the internal electrons are talking to each other.
How does an engineer measure these internal electrons? And what would be a high speed?

I presume that the question is about processor power, and perhaps memory and non-volatile storage. And people are providing meaningful answers.
Reply With Quote
  #16  
Old 04-11-2011, 11:39 PM
beowulff beowulff is online now
Member
 
Join Date: May 2001
Location: Scottsdale, more-or-less
Posts: 11,010
Quote:
Originally Posted by thirdname View Post
I'm surprised an iPhone has so little power. I thought it was like a little computer. I know it has less power than a computer, but I thought it would at least have a tenth the power of a current desktop. Isn't 36 MFLOPS like, a hundredth or a thousandth of a modern desktop, or am I wrong?

I googled attempting to find out the FLOPS of an iMac and ended up on this page: http://www.intel.com/support/process.../cs-023143.htm that lists Intel processors in the tens of GFLOPS.
Floating-point operations aren't particularly important for a hand-held device. For that matter, even desktop machines aren't generally floating-point bound. Integer operations are going to be much more important to overall speed, and so they are what is optimized on the iPhone. Most of the calculations requiring floating point would be for screen rendering, and the iPhone has dedicated hardware for that - hardware that would blow any 30-year-old supercomputer out of the water.
Reply With Quote
  #17  
Old 04-11-2011, 11:50 PM
SeaDragonTattoo SeaDragonTattoo is online now
Member
 
Join Date: Sep 2007
Location: Chicago, Far Northsider
Posts: 5,798
Quote:
Originally Posted by Keeve View Post
(snip)
Can one even use camera, or are those saved in the cloud too?

I suppose I must admit that I'm exaggerating. I think they have calculators that can be used. I guess that brings it to the early 1970s.
I'm not sure when you looked last, but the iPhones have 8, 16, or 32 gigs of memory to store whatever you want on it locally. Take your own photos, store music, games, PDF's, word processing documents, take your own video or watch movies, books, whatever - all to be played back at will, regardless of connection to the web. Depending on what apps are on-board, you can also edit any photos or video you have taken, along with editing documents. If the cloud is unavailable to connect, but there's a hardwired web-enabled computer nearby, you can still connect via USB.

When you are connected to the cloud, you can stream everything and not even use any of that storage to watch youtube, netflix, or music from Pandora, Napster, whatever!

Now what year are we in?
Reply With Quote
  #18  
Old 04-12-2011, 12:28 AM
astro astro is online now
Guest
 
Join Date: Jul 1999
Quote:
Originally Posted by Keeve View Post
First you have to define what you mean by "powerful". One way is by getting an engineer to measure how fast the internal electrons are talking to each other. But if you mean in terms of how much it can accomplish visibly to an ordinary person, I'm guessing that you'd have to go back to before Thomas Edison.

I'm being serious. Beside its usefulness as a flashlight, how much can an iPhone do when there's no network to connect to? One of the reasons I'm staying away from the current generation of smartphones is that all their smarts vanishes when the Cloud is out of reach. Specifically, I was looking for a phone/PDA that would let me edit simple text files and save them on the device (rather than in the cloud), and I couldn't find any. Can one even use camera, or are those saved in the cloud too?

I suppose I must admit that I'm exaggerating. I think they have calculators that can be used. I guess that brings it to the early 1970s.
Per what the others said what in the world are you talking about? Where did you get this notion?

Modern smartphones have all their text editing smarts (and other programs) onboard and can save locally. This has been true ever since the first smartphones came out several years ago. The only apps that are "cloud" dependent are those they rely on an external database or data set of some kind. If you are determined to wait until a smartphone can hold the web offline I think you will be waiting a long, long time.
Reply With Quote
  #19  
Old 04-12-2011, 02:49 AM
Francis Vaughan Francis Vaughan is online now
Guest
 
Join Date: Sep 2009
It is not a clear cut problem to find a historical machine or even system that relates directly to a modern computer, even more so for a smart phone. Relating to a supercomputer is even more difficult because they have really significantly different uses.

A traditional supercomputer has usually been a floating point monster. 64 bit floating point on large regular data. Your average smart phone is notihng special at that particular job, mostly because there is no good reason to provide the capability. On the other hand, pretty much all the other useful capabilities are well taken care of.

Most smart phones are ARM based, with Coretex-8 being very common. Clock rates up to 1GHz, reasonable cache, and with graphics accellerators on many phones. Support for some form of SIMD acceleration, whether proprietory or ARM's NEON, gets things very close to the capabilities of old vector machines like the Crays, but still typically no 64 bit floating point. 32 bit, for games and graphics support yes, but the requirements of the platform just don't need 64 bit.

The old Crays didn't even have caches, they just had very fast memory and massive prefectch that worked well with the vector operations. This meant they didn't slow down like more general purpose machines do when the caches start to thrash.

Even very humble phones have had significant, if very specific, computational power. Running the codecs and encryption engines requires processors with quite a bit of grunt. However the implementations are usually very targetted at the problem. So whilst they may whip an old supercomputer on that one task, they won't beat the supercomputer on what it is good at. There was even a bespoke supercomputer devoted to QCD calculations that tried to leverage the processing power in early phone chipsets. (Lattice Gauge QCD codes require a small matrix kernel on a 8D space that only needs 32 bit float. Thus it turns out to be a nice fit. Most physics problems are not so well contained.)

So, that answer to the OP is really not well defined. You can do a rough match against various metrics on machines back in history, but a smart phone is a very well honed integrated system design, as were the old supercomputers. With very different use cases they are optimised in very different ways. So any comparison is going to find quite diverse answers depending upon the metric you use.
Reply With Quote
  #20  
Old 04-12-2011, 03:11 AM
Reply Reply is offline
Member
 
Join Date: Jul 2003
Location: Arcata, CA
Posts: 7,126
Quote:
Originally Posted by Francis Vaughan View Post
It is not a clear cut problem to find a historical machine or even system that relates directly to a modern computer, even more so for a smart phone. Relating to a supercomputer is even more difficult because they have really significantly different uses.

A traditional supercomputer has usually been a floating point monster. 64 bit floating point on large regular data. Your average smart phone is notihng special at that particular job, mostly because there is no good reason to provide the capability. On the other hand, pretty much all the other useful capabilities are well taken care of.

Most smart phones are ARM based, with Coretex-8 being very common. Clock rates up to 1GHz, reasonable cache, and with graphics accellerators on many phones. Support for some form of SIMD acceleration, whether proprietory or ARM's NEON, gets things very close to the capabilities of old vector machines like the Crays, but still typically no 64 bit floating point. 32 bit, for games and graphics support yes, but the requirements of the platform just don't need 64 bit.

The old Crays didn't even have caches, they just had very fast memory and massive prefectch that worked well with the vector operations. This meant they didn't slow down like more general purpose machines do when the caches start to thrash.

Even very humble phones have had significant, if very specific, computational power. Running the codecs and encryption engines requires processors with quite a bit of grunt. However the implementations are usually very targetted at the problem. So whilst they may whip an old supercomputer on that one task, they won't beat the supercomputer on what it is good at. There was even a bespoke supercomputer devoted to QCD calculations that tried to leverage the processing power in early phone chipsets. (Lattice Gauge QCD codes require a small matrix kernel on a 8D space that only needs 32 bit float. Thus it turns out to be a nice fit. Most physics problems are not so well contained.)

So, that answer to the OP is really not well defined. You can do a rough match against various metrics on machines back in history, but a smart phone is a very well honed integrated system design, as were the old supercomputers. With very different use cases they are optimised in very different ways. So any comparison is going to find quite diverse answers depending upon the metric you use.
I've always heard this, but never quite understood it. Could you provide an example of something that a supercomputer's purpose-designed chip would be better at than a general-purpose one? What exactly is it about the hardware that makes them better-suited to any one thing?
Reply With Quote
  #21  
Old 04-12-2011, 04:31 AM
Francis Vaughan Francis Vaughan is online now
Guest
 
Join Date: Sep 2009
Nowadays there are very few specially designed supercomputer processors, so we have to go back a while, to a more golden age to see the difference. The lack of purpose designed supercomputer chips is mostly to do with economies of scale. With a market for millions of processor chips, the mainstream manufacturers and designers of chips can push the design cycle much faster and design much much more sophisticated systems compared to a niche market like traditional supercomputers.

If we talk supercomputers of yore, we are usually talking big numeric problems. These problems are usually very regular, and often expressible in terms of liner algebra, which means matrix arithmetic. Indeed about half the problems out there were numeric solutions to partial differential equations, which is little more than populate a huge matrix invert, calculate answer, rinse and repeat. The other half were finite element style systems, and again lots of reasonably regular calculations over large data sets. The critical thing about most of these systems is that they need the accuracy of 64 bit floating point. Systems would often simply be too unstable to get useful answers with the error that would creep in with only 32 bit float.

This leads to computer architectures that are very good at very regular application of 64 bit floating point operations to large data sets. Fast floating point means deep pipelines, and large data sets means that you need lots of fast memory. Modern machines depend upon very fast caches that can provide operands inside a very few clock cycles. There is a constant trade-off in cache sizes, bigger caches are slower. Which is why you see such tiny level one caches.

The key to the performance of these older vector machines was that they were designed to operate upon slabs of data at a go - vectors of data. Not only would you have registers of data, like conventional machine, but vector registers, that actually contained say 64 operands. You could emit a single vector instruction and have it apply the operation to all 64 elements. Read and write operations work the same to memory. Because the processor knew at the start of the instruction all the work it needed to do on a very large amount of data it could efficiently muster large resources. In principle multiple ALUs, with deep pipelines could all be usefully employed. Because the operands didn't conflict there was no need for worrying about hazards in the piplelines, or lots of the horrendous tricks used in a modern superscalar design. Probably the last vector was the Cray X1, which was an amazing design, but sadly overtaken by systems based upon commodity x86 processors. With a clock of a pedestrian 800Mhz it still offered 12.8 Gigaflops per processor. 6 years later there still isn't anything that can touch that.

Last edited by Francis Vaughan; 04-12-2011 at 04:32 AM..
Reply With Quote
  #22  
Old 04-12-2011, 08:36 AM
sevenwood sevenwood is offline
Guest
 
Join Date: Aug 2003
Quote:
Originally Posted by Keeve View Post
how much can an iPhone do when there's no network to connect to?
For that matter, that Cray-1 supercomputer I mentioned above couldn't do anything without another computer handing its input and output. Seriously - it had disk drives, but didn't have any I/O capability beyond that.

That situation wasn't unusual in those days. My first job was as a computer operator on a CDC 1604 (I may have that model number wrong) in the mid-sixties. That computer had tape drives, but no other peripherals. My main task was using another computer to perform card-to-tape and tape-to-print operations as a combined front-end and back-end for the 1604.
Reply With Quote
  #23  
Old 04-12-2011, 08:44 AM
chorpler chorpler is offline
Charter Member
 
Join Date: Apr 2002
Location: Vegas, baby!
Posts: 3,259
Quote:
Originally Posted by Keeve View Post
First you have to define what you mean by "powerful". One way is by getting an engineer to measure how fast the internal electrons are talking to each other. But if you mean in terms of how much it can accomplish visibly to an ordinary person, I'm guessing that you'd have to go back to before Thomas Edison.

I'm being serious. Beside its usefulness as a flashlight, how much can an iPhone do when there's no network to connect to? One of the reasons I'm staying away from the current generation of smartphones is that all their smarts vanishes when the Cloud is out of reach. Specifically, I was looking for a phone/PDA that would let me edit simple text files and save them on the device (rather than in the cloud), and I couldn't find any. Can one even use camera, or are those saved in the cloud too?

I suppose I must admit that I'm exaggerating. I think they have calculators that can be used. I guess that brings it to the early 1970s.
I'm curious about which smart phones WON'T let you save and edit local text files. What phones did you look at? Because, as others have said, this is completely incorrect. Heck, Apple makes a ton of money selling iPod Touches, which are basically iPhones with the phone part removed.
Reply With Quote
  #24  
Old 04-12-2011, 11:16 AM
BigT BigT is offline
Guest
 
Join Date: Aug 2008
How do these devices decode MP3s? I remember when I did a short research paper on MP3s in high school, and I learned that the first computer that could decode an MP3 in real time was the Pentium 120 MHz (or maybe it was 133Mhz).

I always equated my third generation iPod with that Pentium. I loaded Linux on it, and it could just barely play MP3s at 160bps. While Apple apparently had a way to play MP3s and still allow you to do other things on the device, I assumed that was a different codec than the general purpose one that would be used in Linux.

Anyways, my point is that, if you actually look at the things the iPhone is good for, I think you'll find it would be the fastest computer a lot later than you think.
Reply With Quote
  #25  
Old 04-12-2011, 11:54 AM
Chronos Chronos is offline
Charter Member
 
Join Date: Jan 2000
Location: The Land of Cleves
Posts: 55,274
Actually, dedicated vector-processing number-crunching computers are still around, and with far greater economies of scale than ever before. Your CPU isn't designed for the same kinds of tasks that the old Crays were, but your video card is. And a lot of high-end scientific computing nowadays is done on video cards.
Reply With Quote
  #26  
Old 04-12-2011, 04:08 PM
Jman Jman is offline
Guest
 
Join Date: Jun 2000
Looking at Geekbench scores, my iPhone 4 scores about 50% better than a PowerPC G4 500MHz and slightly higher than a G4 700. Not bad for in your pocket, I'd say.

Last edited by Jman; 04-12-2011 at 04:09 PM..
Reply With Quote
  #27  
Old 04-12-2011, 05:04 PM
t-bonham@scc.net t-bonham@scc.net is offline
Guest
 
Join Date: Mar 2003
Quote:
Originally Posted by sevenwood View Post
For that matter, that Cray-1 supercomputer I mentioned above couldn't do anything without another computer handing its input and output. Seriously - it had disk drives, but didn't have any I/O capability beyond that.

That situation wasn't unusual in those days. My first job was as a computer operator on a CDC 1604 (I may have that model number wrong) in the mid-sixties. That computer had tape drives, but no other peripherals. My main task was using another computer to perform card-to-tape and tape-to-print operations as a combined front-end and back-end for the 1604.
This was typical of Seymour Cray's designs.
And that design is still used today, for high performance. For example, early PC's had the CPU doing the output for the integrated video; now there are specialized video cards, with their own graphics processor onboard to do that work for the machine.

It was commonly said that you never sold a Seymour Cray machine.

When you were already maxing out your 1 (or 2) CDC 7600's; so you installed a Cray-1, but you kept the 7600's to do the I/O processing for the Cray.
Reply With Quote
  #28  
Old 04-12-2011, 09:57 PM
gonzoron gonzoron is offline
Guest
 
Join Date: Aug 2000
Quote:
Originally Posted by Giles View Post
But could it take photographs and let you browse the Web?
Photographs, no. But you can't name a website available at the time that it couldn't browse.

Reply With Quote
  #29  
Old 04-12-2011, 11:46 PM
Dr. Strangelove Dr. Strangelove is online now
Guest
 
Join Date: Dec 2010
Quote:
Originally Posted by Francis Vaughan View Post
With a clock of a pedestrian 800Mhz it still offered 12.8 Gigaflops per processor. 6 years later there still isn't anything that can touch that.
Recent NVIDIA GPUs can achieve about 500 GFLOPs of double-precision performance per processor at <1200 MHz ALU clocks. Yeah, it's a GPU--but the programming limitations on them are similar to vector processors. They even support supercomputer-type features such as ECC memory.
Reply With Quote
  #30  
Old 04-13-2011, 02:11 AM
septimus septimus is online now
Guest
 
Join Date: Dec 2009
Quote:
Originally Posted by Shagnasty View Post
I don't think an early Cray could do much with any media file without the software to go with it which is another huge part of this question.
The Crays and 7600 were after my time, but in the 6600 the CPU itself was only a sort of "idiot-savant." Most O.S. operations (including all I/O) were handled by the PPU, a separately-architected processor.

The PPU executed ten threads concurrently with a single processor! This mechanism (compared to the rotating barrel of a revolver gun) is an elegant low-cost approach to higher performance. It conflicts with cacheing, but cacheing is a high-cost approach to speed, so I'm surprised Cray's barrel got little further interest, or did it?
Reply With Quote
  #31  
Old 04-13-2011, 04:14 AM
Francis Vaughan Francis Vaughan is online now
Guest
 
Join Date: Sep 2009
Quote:
Originally Posted by Dr. Strangelove View Post
Recent NVIDIA GPUs can achieve about 500 GFLOPs of double-precision performance per processor at <1200 MHz ALU clocks. Yeah, it's a GPU--but the programming limitations on them are similar to vector processors. They even support supercomputer-type features such as ECC memory.
A Nvidia T20 GPU can clock in at 515 GFlops of double precision. But it isn't a single core, rather it contains 448 cores. That is still pretty damn impressive. But the Cray X1 was a single core. It was also based upon a MIPS ISA, and could be used as a general purpose processor (albeit no faster than any other 800MHz MIPS processor.)

On the other hand, Cray now ship machines that can be filled with GPU boards, and they killed the X1 5 years ago, so it is pretty clear how things have worked out. But it is hard to take it away from the X1, it was an amazing bit of work. It was later available as a dual core chip, but things were already winding up for it by then. However, had the X1 been a success we would probably be seeing eight+ core chips with 3+GHz clocks, and processing capability lineball with GPUs and with possibly an easier to use ISA. But no market sizeable enough to support it.
Reply With Quote
  #32  
Old 04-13-2011, 07:50 AM
Keeve Keeve is offline
Guest
 
Join Date: Aug 2000
Quote:
Originally Posted by chorpler View Post
I'm curious about which smart phones WON'T let you save and edit local text files. What phones did you look at? Because, as others have said, this is completely incorrect. Heck, Apple makes a ton of money selling iPod Touches, which are basically iPhones with the phone part removed.
Yeah, I seem to have gotten two different issues confused. You and I discussed my search for a smartphone in January in this thread. But looking back at it, I see that part of my problem was that I also wanted a physical keyboard, and that's missing from a lot of the modern phones.

BTW, I ended up getting a cheap used Palm Centro on eBay. It is an AT&T one, so I simply put my SIM card into it, and was using it and loving it for about a month. I never used any of its data abilities, because I didn't want to pay for the data plan, and was more than happy to have a phone and a PDA in the same device. Then AT&T discovered that I was using a smartphone for my phone calls, and informed me that this requires me to pay for a data plan. I argued with them for about 2-3 hours across 4-5 calls, telling them that it is a totally legal AT&T phone that I didn't jailbreak or anything, and that I'm not using the data features and I shouldn't have to pay for the data features. With great difficulty they were able to show me where the contract says that I'm required to get a data plan simply because I'm using a smartphone. So, rather than pay their extortion fee, I put the SIM card back into my dumbphone, and now I have two separate devices in my pocket. It turns out that the inconvenience of having two devices is balanced by having double the battery power!
Reply With Quote
  #33  
Old 04-13-2011, 07:56 AM
Musicat Musicat is offline
Charter Member
 
Join Date: Oct 1999
Location: Sturgeon Bay, WI USA
Posts: 17,535
Quote:
Originally Posted by Terry Kennedy View Post
In the late 70's I was fooling around at a recording studio and used an S-100 computer to digitize, store, and play back audio. This was with 8-bit sampling at a low (several KHz) rate. That was well before there were CDs - the basic format was probably defined at the time I did my audio work, but the availability of audio CDs was several years away.

The main limitation was the cost of storage (both main memory and disk) - in the mid to late 70's disk drives that stored anywhere from 5MB to 200MB were the size of washing machines and very expensive. A typical hobby computer had somewhere between 8KB and 64KB of main memory and (if a high-end system) perhaps 512KB of disk (a pair of single-density 8" floppies).
I did stuff like that on an IMSAI 8080, too, but with 48K RAM (64K cost too much and we had to allow for EPROM addressing space), we could only capture a few seconds of single-channel audio. Kinda made it difficult to store Elton John's Greatest Hits album.

And real-time compression was out of the question since the CPU wasn't fast enough.
Reply With Quote
  #34  
Old 04-13-2011, 11:59 AM
Ruminator Ruminator is offline
Guest
 
Join Date: Dec 2007
Quote:
Originally Posted by Reply View Post
I've always heard this, but never quite understood it. Could you provide an example of something that a supercomputer's purpose-designed chip would be better at than a general-purpose one? What exactly is it about the hardware that makes them better-suited to any one thing?
If Francis Vaughan's good comments are too technical, I'll try and offer an analogy.

Let's say computer chip manufacturers use the basic building blocks of electrical circuits. If they arrange them a certain way, it can be optimal for integer calculations. If they arrange them another way, it can be optimal for floating point. Of course, you can have a computer with both types of circuits but there's an inherent space and power limitation inside the enclosure so the computer designers consider the type of "tasks" it's intended for and can favor the architecture that is most appropriate.

For the analogy, consider making computation devices out of the basic building blocks of wood and sticks. One approach might be a wood abacus (see photos). This type of device would be optimal for integer type of computations. Another approach with wood is to construct slide rules (see photos). This is great for multiplying/dividing large numbers and floating point calculations. Notice you'll have a similar limitation as the computer chips above: in a given volume of physical space, you can't construct a piece of wood that's optimal at both types of calculations. However, if you prioritize the "tasks" you want to solve, you'll know ahead of time which computational device is more appropriate. Now, a big point to emphasize is that you can do floating point operations on the abacus, but it requires more "rules" and many more manipulations of the fingers shifting beads around. It's "slower" than the slide rules dedicated to that type of calculation.

If you need a device to tally votes or count vertices on a graph, the devices optimized for integer operations is fine. If you need to calculate vectors of stars or ballistics trajectories, you'll want something with horsepower dedicated to floating point.

As a disclaimer, I know my analogy is incomplete but one can keep adding details to it until you have the equivalent of a PhD in electrical engineering and can design computer chips from the raw materials of sand.
Reply With Quote
  #35  
Old 04-13-2011, 12:51 PM
gazpacho gazpacho is offline
Charter Member
 
Join Date: Oct 1999
Posts: 5,125
Vector processing is alive and well. Especially in the cell phone industry. Many digital signal processors have something very much like the vector math processors of old super computers. For pretty much the same reason the old super computers did. There is a huge amount of math that is done to get the high data rates out of the cell phone modems. Some of this math is done in specific dedicated hardware some of it is done in more general purpose DSPs. A trend is to move more of the stuff in dedicated hardware to more powerful DSPs with vector processing engines. All this vector processing stuff is done in different processors from the application processor that runs the apps you get for your iphone or android phone.

BigT the phones I am familiar with have separate DSPs that handle the heavy computations for MP3 and movie decoding and encoding.
Reply With Quote
  #36  
Old 04-13-2011, 11:42 PM
Dr. Strangelove Dr. Strangelove is online now
Guest
 
Join Date: Dec 2010
Quote:
Originally Posted by Francis Vaughan View Post
A Nvidia T20 GPU can clock in at 515 GFlops of double precision. But it isn't a single core, rather it contains 448 cores. That is still pretty damn impressive. But the Cray X1 was a single core. It was also based upon a MIPS ISA, and could be used as a general purpose processor (albeit no faster than any other 800MHz MIPS processor.)
I wouldn't equate a GPU core with a CPU core. They aren't equivalent in functionality. GPU processing is arranged somewhat hierarchically, with clusters of "cores" and clusters of clusters. Unlike CPU cores, GPU cores can't operate independently, and in reality more resemble a single slice of a vector unit on a CPU.

So while it may be true that the Cray X1 had the fastest single-core FP throughput per clock, for some definition of a "core", to me that seems like too limiting a definition given the variety of implementations out there. In terms of what's been packed onto a single die, the X1 has been beaten.
Reply With Quote
  #37  
Old 04-13-2011, 11:56 PM
Dr. Strangelove Dr. Strangelove is online now
Guest
 
Join Date: Dec 2010
Quote:
Originally Posted by septimus View Post
It conflicts with cacheing, but cacheing is a high-cost approach to speed, so I'm surprised Cray's barrel got little further interest, or did it?
There's been plenty of interest. Most recent Intel CPUs support "Hyper-Threading", which is 2 threads per physical core. IBM has similar technology for its POWER architecture. And Sun's UltraSPARC Tx-series has a barrel-type arrangement with 4 or 8 threads per core.

Probably the main reason why there isn't even more interest is because massively-threaded systems are useful mainly for servers; on the desktop, single-thread performance is still crucial.
Reply With Quote
  #38  
Old 04-14-2011, 01:23 AM
chorpler chorpler is offline
Charter Member
 
Join Date: Apr 2002
Location: Vegas, baby!
Posts: 3,259
Quote:
Originally Posted by Keeve View Post
Yeah, I seem to have gotten two different issues confused. You and I discussed my search for a smartphone in January in this thread. But looking back at it, I see that part of my problem was that I also wanted a physical keyboard, and that's missing from a lot of the modern phones.

BTW, I ended up getting a cheap used Palm Centro on eBay. It is an AT&T one, so I simply put my SIM card into it, and was using it and loving it for about a month. I never used any of its data abilities, because I didn't want to pay for the data plan, and was more than happy to have a phone and a PDA in the same device. Then AT&T discovered that I was using a smartphone for my phone calls, and informed me that this requires me to pay for a data plan. I argued with them for about 2-3 hours across 4-5 calls, telling them that it is a totally legal AT&T phone that I didn't jailbreak or anything, and that I'm not using the data features and I shouldn't have to pay for the data features. With great difficulty they were able to show me where the contract says that I'm required to get a data plan simply because I'm using a smartphone. So, rather than pay their extortion fee, I put the SIM card back into my dumbphone, and now I have two separate devices in my pocket. It turns out that the inconvenience of having two devices is balanced by having double the battery power!
See, I knew you must be thinking of something else, because I remember discussing this with you a few months ago and PMing about it.

I'm very very nervous about AT&T buying out T-Mobile now that you've posted this. And I was already plenty nervous.
Reply With Quote
  #39  
Old 04-14-2011, 08:44 AM
Francis Vaughan Francis Vaughan is online now
Guest
 
Join Date: Sep 2009
Quote:
Originally Posted by Dr. Strangelove View Post
There's been plenty of interest. Most recent Intel CPUs support "Hyper-Threading", which is 2 threads per physical core. IBM has similar technology for its POWER architecture. And Sun's UltraSPARC Tx-series has a barrel-type arrangement with 4 or 8 threads per core.

Probably the main reason why there isn't even more interest is because massively-threaded systems are useful mainly for servers; on the desktop, single-thread performance is still crucial.
The granddaddy of hyper threading was/is the Tera MTA (Muti-threaded-architecture).
For a long time it was really the only new idea in computer architecture. Tera pushed the idea for quite a time, and actually made (a few) machines. When Tera bought Cray (a minnow swallowing a whale) the MTA continued on for a while, but was killed. Burton Smith, who was the leading light, left and joined the evil empire.

The MTA was amazing. The second version had 256 threads, and it would switch contexts each clock cycle. It had no data caches, but latency to memory was - surprise surprise - about 256 cycles. So a thread always saw its operands. It has other neat archtictural features, especially tagged memory. The big big problem was getting a compiler to make use of so many threads. I heard Burton talking the MTA up in 1996, and some years later he was using exactly the same benchmark results - a massive parallel sort. There is a clear lineage from the MTA to hyperthreading and the other multi threaded designs.
Reply With Quote
  #40  
Old 04-14-2011, 08:52 AM
Francis Vaughan Francis Vaughan is online now
Guest
 
Join Date: Sep 2009
Quote:
Originally Posted by Dr. Strangelove View Post
I wouldn't equate a GPU core with a CPU core. They aren't equivalent in functionality. GPU processing is arranged somewhat hierarchically, with clusters of "cores" and clusters of clusters. Unlike CPU cores, GPU cores can't operate independently, and in reality more resemble a single slice of a vector unit on a CPU.
No argument there. Eventually all that matters is what you can do with a given area of silicon. GPUs remind me much more of classic SIMD machines, machines like the CM-2 and CM-5.

It is worth mentioning that vector supercomputers are not really dead. But they are very niche. NEC still makes the SX9, which gets 100GFlops per core. They must do it for love. OTOH, for the right problem they are amazing.

Matching the architecture to the problem has always been the big issue with the very high end supercomputing. This is why machines like the SX9 and SGI UV still exist.

Last edited by Francis Vaughan; 04-14-2011 at 08:54 AM..
Reply With Quote
  #41  
Old 10-23-2012, 07:27 PM
jojomonkeyboy jojomonkeyboy is offline
Guest
 
Join Date: Oct 2012
This is comparing desktop to supers of the 80s but can also apply to ipads as well

When comparing performance of your average desktop to the crays of the early 1990s or even 80s, you must take into consideration not the "peak mflop" ratings but the sustained mflop ratings. Peak mflops mean little if the machine never reaches such performance levels. The Army actually analyzed the cost/benefit of having a cluster of p4 2.8 ghz or going with a cray solution. They discovered that although the p4 2.8 ghz had a high peak mflop rating of 5.6gflops, in practice it only reached %3.4 of its peak performance due to bandwidth limitations! Please see the results of the army's study right here https://cug.org/5-publications/proce...zio_slides.pdf Needless to say their conclusion was that the cray solution was more cost effective and easier to program and maintain.
Nasa's high performance computer lab also did a comparison between their old cray xmp 12 (one processor 2 megawords of memory) and a dual pentium II 366 running windows NT. They had to redesign the space shuttle's solid rocket boosters back in the late 80s after the challenger disaster and the cray xmp was used to model air flow and stresses on the new design. Some years later the code was ported to a windows NT workstation and the simulation rerun for comparison. The result is that a single processor cray xmp was able to compute the simulation in 6.1 hours versus 17.9 hours on the dual pentium II. The cray xmp could have up to four processors with an aggregate bandwidth of over 10gb a sec. to main memory, this kind of SUSTAINED bandwidth between cpu (not gpu) and main memory was not matched on the desktop until about 4 years ago. The pentium IIs had either a 66mhz or 100mhz bus speed so we are talking a maximum bandwidth of only 800mb (528mb with 66mhz bus) and with around 330mb/sec transfer rates sustained (remember pc's use dram and the crays mostly used very expensive sram memory). The importance of bandwidth and real world number crunching performance can be seen in the STREAM benchmark. Please go to http://www.streambench.org/ to see exactly what I mean.
In 1990 the C90 cray was the baddest super computer on the planet, and at $30 million fully configured it was also by far the costliest. Here's a photo of it: http://www.cisl.ucar.edu/zine/96/fall/images/c90.gif. The cray c90 could have up to 16 processors, with 16gb of memory, and could achieve a maximum performance of around 16glfops. "Well gee, my cheapo phenom x6 can do well over 16 gflops because that's what it says on my sisoft sandra score so I have a cray c90 sitting under my desk blah blah..." you are completely wrong if you think this. The sisoft sandra benchmark tests everything in cache which is easy for the cpu to access. Real world problems, the kind that crays are built to solve, can't fit into a little 4mb cache and thus we come to sustained bandwith problems. The c90 can fetch 5 mega words per clock cycle (for each processor) from main memory and has a real world bandwidth of 105gb/sec; compare this to a relatively modern, quad processor (4 processors and 16 cores) core i7 2600 that gets a measly 12gb a second sustained bandwidth. "But the core i7 2600 is clocked much higher than the c90 which only operate at 244mhz per processor". Ahhh but if the data is not available for the processor to operate on then it just sits there, wasting all cycles, waiting for the memory controller to deliver data to it. Without getting into too much detail (if you want a lot of detail read my analysis of the cray 1a versus pentium II below) the real world mflops of the C90, working on data sets too large for a typical pcs small cache, works out to roughly 8.6 gflops while the Intel Core i7 2600 will achieve only about 1gflops sustained on problems out of cache. So far there are no desktops, and won't be for quite a few years, that come EVEN close to the real world sustained bandwidth (and thus sustained performance) of a C90. Now for problems that do fit into the tiny cache and can be mostly pre-fetched, of course the desktop will be superior to the old crays. Here is a rough comparison I made between a cray 1a and a pentium II 400, read on only if you want to be bored to death:

The Cray 1A had a clock cycle time of 12.5 ns, or an operational frequency of 80 mhz. It had three vector functional units and three floating point units that were shared between vector and scalar operands in addition to four scalar units. For floating point operations it could perform 2 adds and a multiply operation per clock cycle. It had a maximum memory configuration of 1 million megawords or 8 megabytes at 50ns access time interleaved into 16 banks. This interleaving had the effect of allowing a maximum bandwidth of 320 million megawords into the instruction buffers or 2560 mb/sec. Bandwidth to the 8 vector registers of the Cray 1A could occur at a maximum rate of 640 mb/sec. The Cray !A possessed up to eight disk controllers each with one to four disks, and each disk having a capacity of 2.424X10^9 bits for a maximum total hard disk capacity of 9.7 gigabytes. There were also 12 input/output channels for peripheral devices and the master control unit. It cost over 7 million in 1976 dollars and weighed in at 10,500 lbs with a power requirement of 115 kilo watts. So how does this beast compare with myr old clunker of a PC with 384 mb of SD100 ram and a P2 400 mhz cpu?

Well lets take a simple triad operation, with V representing a vector register and S representing a scalar register.

S*V0[i] + V1[i] = V2[i]

Without getting into too much detail this equation requires 24 bytes of data to perform once. There are two floating point operations going on here, the multiplication of the scalar value with the vector, then the addition of the second vector.Thus, assuming a problem too large to just loop in the cray 1A registers, and a bandwidth of 640 mb/s, the maximum performance of a Cray1A would equal (640/24) * 2 = 53 mflops on large problems containing data which could not be reused. This figure correlates well with the reported performance of the Cray 1A on real world problems

http://www.ecmwf.int/services/comput...r_history.html.

True bandwidth on a Cray 1A would also have to take into account bank conflicts plus access latency so about 533 mb/sec sustained is a more realistic figure. On smaller problems with reusable data the Cray 1A could achieve up to 240 mflops by utilizing two addition function units and one multiplication function unit simultaneously through a process called chaining. So you see the Cray 1A could be severely bandwidth limited when dealing with larger heterogeneous data sets.

My pentium II 400 has 512 kb of L2 cache, 384 mebabytes of SD100 ram, and a 160gb 7200 rpm hard drive. Theoretically it can achieve a maximum of 400 mflops when operating on data contained in its L1 cache, although benchmarks like BLAS place its maximum performance at 240 mflops for double precision operations which is what we are interested in here. Interestingly this is about the same as what a Cray !A can do on small vectorizable code. However once we get out to problem sizes of 128kb or 256kb or even 512kb my pentium 2 would beat the Cray 1A even in its greatest strength, double precision floating point operations, due to the bandwidth advantage of the L2 cache over the Cray's memory. At 1600 mb/s bandwidth my computer can do up to 133 mflops for problems under 512 kb in size but greater than the L1 Cache.

Once we get beyond 512 kilobytes the situation shifts as data would then need to be transferred from the SD100 ram.The theoretical bandwidth of SD100 ram is 800 mb/sec, still greater than the Cray 1A but here we run into some issues. The Cray 1A had memory comprised of much more expensive SRAM, while my memory is el crapo DRAM which require refresh cycles. So with these taken into account my DRAM actually has a theoretical maximum bandwidth of about 533mb/s and a real world maximum sustained bandwidth of a little over 300mb/s. This means that for problems out of cache, my pentium 2 gets slowed to a measly 315/12 = 26 mflops. In this special situation where the problem is vectorizable, the Cray 1A is still faster than my pentium 2, not bad for a computer that is 30 years old.

Once we get problems greater than 8 megabytes, the advantage shifts completely back to my pentium II as the Cray !A must then stream data from its hard disks (which were slower than ultra ATA/100) and my computer can go right on fetching data from ram. The Cray 1A could not realize its full potential as it was hampered by bandwidth
and memory size issues, yet in certain situations could outperform a desktop computer from 1998. Solid state disks,more memory ports, and larger memories were utilized in the subsequent cray xmp to address these problems.

A desktop like the core duo E6700 can do over 12 gigaflops, BUT only on problems that are small and fit into its cache. Once the data gets out of cache today's modern computers get their butts kicked by the old school Crays from the 80s. Just visit http://www.streambench.org/ to see what I mean.

Last edited by jojomonkeyboy; 10-23-2012 at 07:28 PM..
Reply With Quote
Reply



Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 01:59 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.

Send questions for Cecil Adams to: cecil@chicagoreader.com

Send comments about this website to: webmaster@straightdope.com

Terms of Use / Privacy Policy

Advertise on the Straight Dope!
(Your direct line to thousands of the smartest, hippest people on the planet, plus a few total dipsticks.)

Publishers - interested in subscribing to the Straight Dope?
Write to: sdsubscriptions@chicagoreader.com.

Copyright 2013 Sun-Times Media, LLC.