No Intel only plan to refresh the Xeon UP and DP series with Nehalem in Q1 2009. They will only offer QPI for 4P+ systems in late 2009, when they release their Nehalem-based Xeon MPs. So it is safe to say that AMD will continue to dominate the 4P market for at least 1 more year.
I wouldn't be so quick to say that AMD has lost it all.
First of all, in the 4 and 8-socket market, AMD still has no competition.
The Intel Xeon MP series is still using the outdated FSB technology.
This series also requires expensive and power-consuming FB-DIMM modules instead
of DDR2/DDR3. Nehalem-based Xeon MPs are not going to ship before Q4 2009.
Etc.
Secondly, in the 1-socket and 2-socket market, and regarding the latest 45nm
AMD Shanghai and Intel Nehalem, so far there are very few
benchmarks comparing directly the 2 microarchitectures; most of the hardware
review sites do the mistake of comparing Shanghai against the older Intel
generation, or the older AMD generation
against Nehalem. But from what I have seen, clock-for-clock, for most
workloads, Shanghai and
Nehalem are very close, +/-10% in terms of performance, and Shanghai seems
to do this in the same or a slightly lower power envelope.
Some workloads do exhibit a more significant performance difference, with
either Shanghai or Nehalem pulling ahead of its competitor. Now comparing
clock-for-clock isn't really what matters. What matters is dollar-for-dollar
comparisons. But what is interesting is that AMD has priced the Shanghai
Opterons 23xx to match very closing the Nehalem Xeon 55xx series at equivalent
frequencies. This tends to indicate that AMD thinks that they offer a
clock-for-clock value identical or better than Intel.
The only area where AMD will clearly be unable to compete in the 1 and
2-socket market is the very high end: 1-socket Shanghai processors
will top out at 3.0 GHz, 2-socket processors will top out at 2.8 GHz,
while Intel goes all the way up to 3.2 GHz. However these expensive processors
represent a very small proportion of the market share (virtually nobody
buys $1000+ processors), so it shouldn't be a huge factor regarding
which processor manufacturer "wins" this 45nm battle. Intel will have
the bragging rights, but that's about it.
Another last point I would like to mention is that AMD will be the only
one to offer low-power 1-socket 45nm Shanghai for at least the entire
first half of 2009: 55W and 75W ACP Opteron 13xx, and 95W TDP Phenom II.
While Intel will only offer Core i7 and Xeon 35xx processors rated at
130W TDP (!). They are planning to release lower-power 45nm Nehalems only during
the second half of 2009. I find it rather stunning for Intel to not care
more about power consumption... especially for their Xeon 55xx line, the
server market cares about energy efficiency. We all remember that
extravagant power consumption and temperature was a
major factor that caused the failure of the Pentium 4 Netburst
microarchitecture...
You are so true about virtualization. Just 2 or 3 weeks ago I was benchmarking Linux and Windows VMs compiling Java code under Qemu/KVM-75 on an 2-socket 8-core 2.0GHz Opteron 2350 (non-Shanghai) system, and on a 1-socket 4-core 2.4GHz Core 2 Q6600 system. The VMs were configured with 1, 2, or 4 virtual processors and not more, to not give an unfair advantage to the AMD system which had twice the number of cores. Despite the lower CPU frequency as well as lower memory throughput and latency (registered DDR2-667 vs. unbuffered DDR2-800 for Intel), the AMD system was kicking the ass of the Intel system in every case by as much as 10-30%. Most likely this was because of the integrated memory controller and support of nested paging (aka "Rapid Virtualization Index"). Now Intel has cloned these 2 features in their Nehalem microarchitecture. I am very impatient to see how they perform.
The Opteron 1xxx series is using the same AM2+ socket as the Phenom processors, and are in fact rebranded Phenoms (no technical difference). But you are correct in that Opteron 2xxx and 8xxx are completely different animals.
The Opteron 8xxx series is for systems with 4 or more sockets (not restricted to 4). This is made possible because each of the 3 HT links per processor is running the cache coherency protocol (whereas only 1 out of the 3 HT link of an Opteron 2xxx runs the protocol).
Well the support center that handled your call was most likely in India. And
you are in Afghanistan, pretty close right ? And you have ammos... lots ! I'd
say, launch an offensive. Send in your platoon. 30-50 men should be ample
sufficient for a small support center. M16's, grenades, everything. Pretty sure
the support script the guy was reading is not going to provide him the "next
step to follow" in this situation. He'll have no choice but to find you a
laptop on the spot.
One 10-20W Intel IGP: ~$20.
Two 130W quad-core Core i7 920 processors: $568
Using the latter to barely manage to match the performance of the first: priceless.
Remind me to short MSFT when the market opens tomorrow morning.
It's because you are confusing quickness with rapidness. See this drive has a quickness about 3.5x better than regular drives, but a 10x higher rapidness ! They also improved the speediness by about 5x.
YOU CAN NOT DO THIS WITH SHIT PASTED TOGETHER FROM PARTS AT NEWEGG.
Of course you can. The lack of technical details in your post
proves you have no idea what it takes to build servers comparable to
what storage vendors sell, and what is exactly the value that they
offer when you buy these at over $1200/TB.
Take a concrete example: Thumper X4540. Sun use the same Opteron
2300 series processors you can buy on newegg. They use the same nVidia
chipsets MCP55 and IO55 you find on many motherboards from newegg. They
use the same LSI SAS 1068e chips you can find on the Supermicro card
AOC-USAS-L8i recommended by Sun ZFS engineers themselves. They use the same
enterprise-class SATA drives (Seagate IIRC) you can buy from newegg.
They use DDR2 modules based on the same OEM RAM chips used by many
memory vendors selling on newegg. And all the technology is the same:
same PCI-E links, same 10GbE technology, same SATA links, etc.
The only major custom-designed electronic component in the X4540 is the
motherboard (mostly because they had to connect the 3 PCI-E slots to an
IO55 chipset linked to an independent HT link because the sequential
throughput of the 48 disks already use about 70% of the throughput
of the two other 2000MT/s HT links: 48 * 120 MB/s / (2 * 4000 MB/s) = 0.72).
But this custom motherboard is a pretty much unique requirement for the
X4540 -- 99% of the storage servers on the market are far from being
able to saturate 2 HT links as almost nobody else packs 48 drives in 4U.
The value of what Sun sells is twofold. They validate the platform as a
whole: compatibility of the components, thermal/power characteristics,
basic assessment of the failure rate of components, etc (something you
may not know how to do, but system integrators such as me have been doing
for years successfully). And they offer a bunch of "enterprise" features
that are irrelevant to this discussion about performance and reliability
of the I/O subsystem (mechanical design of the chassis, drive bays,
IPMI and other monitoring features, etc).
This myth that storage vendors have access to "superior" technology has
to stop. As always, I'll conclude by citing the example of Google that
started by building their datacenters out of OEM parts with motherboards
and drives literally velcro'd together. Perfect example of good system
integrators hired to do the job in-house instead of buying from storage
vendors...
Due to deliberate licensing issues we won't have native ZFS in Linux any time soon.
It's funny how this viewpoint is always the one promoted on slashdot. One could argue that the Linux GPL is the problem. FreeBSD and Mac OS X had no problem integrating ZFS into their code precisely because the ZFS license (CDDL) allowed it.
You know your "x% of the Sun price" comment makes me think that no storage vendor offers anything between the $120/TB and $750/TB range. Disks sell for $120/TB raw; DIY solutions (counting the PC hardware) can be doable around $200-250/TB; and the less expensive offerings from storage vendors always sell above the $750/TB mark. Something tells me a storage startup targetting the $300-500/TB range would be very, very successful...
An additional 48GB of RAM and 18GB of SSD are not worth $50k. Seriously... Registered ECC DDR2 RAM is about $50/GB and SSD about $20/GB (gross overestimation): they are really worth 48*50 + 18*20 = $2760... Sun is charging 18x more !
Also the 7210 with 48x250GB is strictly equivalent to the X4540 with 48x250GB (same amount of RAM, no SSD), but is $13k more expensive... for the same box ! That is outrageous.
The X4540 is even better to prove your point as it is cheaper than the X4500:
12TB (48x250GB) - $21,995.00
and is virtually identical to the new 7210 box (config with 48x250GB) that sells for $34,995.00. Therefore proving that the same hardware is sold at a 60% markup !
Someone mod the parent up, he laid out the perfect counter-argument to the GP.
Last I checked Netapp was still charging $10,000 per TB! Do you really think there is no reason for this?
Absolutely. The storage industry has always been a particularly profitable market precisely because buyers think
these prices are justified. IMHO it's caused by a lack of competition in the high-end market (competiton is much more
fierce in the entry-level and mid-range market). As someone pointed out, Google built a highly reliable platform and
is certaintly not paying $10k/TB. Read about Google FS.
A friend of mine who works for a storage vendor that should remain nameless fully admits that they can sell some systems at 4-5x their
OEM prices only because their customers, like you, think that "it must be worth it".
Look at, as pointed out by another poster, the diff between a
Thumper x4540
with 48 x 250GB SATA drives at $22k and a
Sun
Storage 7210 with 48 x 250GB SATA drives at $35k.
This is a $13k price difference for virtually the same box.
Beside even the x4540 is overpriced (another friend of mine bought one with
the smallest drives and replaced them with 1TB from Dell to end up
saving $20k to his employer).
So, no this practice of overpricing in the storage industry is not justified ! I have been saving tens of thousand of dollars
by buying and building my own servers from newegg and literally "throwing a few drives in 2U chassis" (and throwing ZFS on top of it) and guess
what ? It works pretty well ! Obviously not everybody can do it (don't build your servers if you don't know the diff between 1.8V and 2.0V RAM,
or the effect of a 75W vs. 120W processor in a 1U chassis, etc), but if you can do it, you will save non-negligible amounts of money to your employer. This is
important both for small startups who have to run as efficiently as possible, as well as Fortune500 like Google who have to scale efficiently.
But sure, if you have the money and don't mind getting ripped off by storage vendors, go ahead, it's your money:) I don't deny they sell high-quality hardware, it's just unnecessarily expensive.
It's a Bash extension that lets you runs processes connected to a FIFO or/dev/fd devices. Example to diff the output of 2 commands without using temporary files:
Only the highest-end processor, Core i7 965 Extreme Edition, supports QPI
at 6.4 GT/s. The 920 and 940 support only 4.8 GT/s. So the amount of
bandwidth on a QPI link is:
6.4 GT/s * 20 bits/direction / 10 bits/byte (8b-10b encoding!) = 12.8 GB/s per direction (25.6 GB/s per link)
4.8 GT/s * 20 bits/direction / 10 bits/byte (8b-10b encoding!) = 9.6 GB/s per direction (19.2 GB/s per link)
This is comparable to the HyperTransport bandwith of a Phenom processor (4.0 GT/s), which
AMD is supposed to scale to 5.2 GT/s in the near future IIRC:
5.2 GT/s * 16 bits/direction / 8 bits/byte = 10.4 GB/s per direction (20.8 GB/s per link)
4.0 GT/s * 16 bits/direction / 8 bits/byte = 8.0 GB/s per direction (16.0 GB/s per link)
Re:why bother with 6 month release cycle?
on
OpenBSD 4.4 Released
·
· Score: 2, Informative
Those SPARCs are 4 year old machines.
No, the UltraSPARC T2 was released in October 2007.
Your datapoint is irrelevant. Because today's processors are much
faster and because the cipher implementations have been improved,
it is now much less costlier to encrypt data. Here are some
"openssl speed" benchmarks of the RC4 symmetric cipher
on a current processor and one released 8 years ago with a
version of OpenSSL almost as old:
This is a 17x improvement in performance ! Run the quad-core
processor in 64-bit mode and it would probably be 20x faster.
By comparison, disk throughput has increased by only about 2x over
the last 8 years (50 MB/s vs. 100 MB/s). So run the same test today
but replace your 8 Xeon 800 MHz with 8 quad-core processors with 12
disks and you should see almost no speed decrease caused by a well-designed
disk encryption app (I can vouch for dm-crypt).
Seriously why does everybody seem to care that much about taxes ? The tax differences between McCain's plain and Obama's plan will not amount to more than a few hundred bucks per year for the average taxpayer. Care about how the next president is going to run the country, economy, healthcare, international relations, not about a few hundred bucks.
it is more difficult for two files of the same size to have the same hash by chance.
This is false. Case in point: the first MD5 collision announced by Wang and his team in 2004 affected 2 data blocks of the same size. More generally, all cryptographically secure hashing algorithms are designed to output a hash as random as possible, no matter what the input size is.
The words "Golomb ruler" are displayed in a dark green color by your browser. Placing the mouse pointer over them usually transforms it in a hand. This is called an "hyperlink", or more commonly, "link". By clicking on it, you are redirected to a page from a site called "Wikipedia", a free, multilingual online encyclopedia project. This page explains what a Golomb ruler is. HTH.
Slashdot Mirror
No Intel only plan to refresh the Xeon UP and DP series with Nehalem in Q1 2009. They will only offer QPI for 4P+ systems in late 2009, when they release their Nehalem-based Xeon MPs. So it is safe to say that AMD will continue to dominate the 4P market for at least 1 more year.
I wouldn't be so quick to say that AMD has lost it all.
First of all, in the 4 and 8-socket market, AMD still has no competition. The Intel Xeon MP series is still using the outdated FSB technology. This series also requires expensive and power-consuming FB-DIMM modules instead of DDR2/DDR3. Nehalem-based Xeon MPs are not going to ship before Q4 2009. Etc.
Secondly, in the 1-socket and 2-socket market, and regarding the latest 45nm AMD Shanghai and Intel Nehalem, so far there are very few benchmarks comparing directly the 2 microarchitectures; most of the hardware review sites do the mistake of comparing Shanghai against the older Intel generation, or the older AMD generation against Nehalem. But from what I have seen, clock-for-clock, for most workloads, Shanghai and Nehalem are very close, +/-10% in terms of performance, and Shanghai seems to do this in the same or a slightly lower power envelope. Some workloads do exhibit a more significant performance difference, with either Shanghai or Nehalem pulling ahead of its competitor. Now comparing clock-for-clock isn't really what matters. What matters is dollar-for-dollar comparisons. But what is interesting is that AMD has priced the Shanghai Opterons 23xx to match very closing the Nehalem Xeon 55xx series at equivalent frequencies. This tends to indicate that AMD thinks that they offer a clock-for-clock value identical or better than Intel.
The only area where AMD will clearly be unable to compete in the 1 and 2-socket market is the very high end: 1-socket Shanghai processors will top out at 3.0 GHz, 2-socket processors will top out at 2.8 GHz, while Intel goes all the way up to 3.2 GHz. However these expensive processors represent a very small proportion of the market share (virtually nobody buys $1000+ processors), so it shouldn't be a huge factor regarding which processor manufacturer "wins" this 45nm battle. Intel will have the bragging rights, but that's about it.
Another last point I would like to mention is that AMD will be the only one to offer low-power 1-socket 45nm Shanghai for at least the entire first half of 2009: 55W and 75W ACP Opteron 13xx, and 95W TDP Phenom II. While Intel will only offer Core i7 and Xeon 35xx processors rated at 130W TDP (!). They are planning to release lower-power 45nm Nehalems only during the second half of 2009. I find it rather stunning for Intel to not care more about power consumption... especially for their Xeon 55xx line, the server market cares about energy efficiency. We all remember that extravagant power consumption and temperature was a major factor that caused the failure of the Pentium 4 Netburst microarchitecture...
You are so true about virtualization. Just 2 or 3 weeks ago I was benchmarking Linux and Windows VMs compiling Java code under Qemu/KVM-75 on an 2-socket 8-core 2.0GHz Opteron 2350 (non-Shanghai) system, and on a 1-socket 4-core 2.4GHz Core 2 Q6600 system. The VMs were configured with 1, 2, or 4 virtual processors and not more, to not give an unfair advantage to the AMD system which had twice the number of cores. Despite the lower CPU frequency as well as lower memory throughput and latency (registered DDR2-667 vs. unbuffered DDR2-800 for Intel), the AMD system was kicking the ass of the Intel system in every case by as much as 10-30%. Most likely this was because of the integrated memory controller and support of nested paging (aka "Rapid Virtualization Index"). Now Intel has cloned these 2 features in their Nehalem microarchitecture. I am very impatient to see how they perform.
Well to be pedantic:
Well the support center that handled your call was most likely in India. And you are in Afghanistan, pretty close right ? And you have ammos... lots ! I'd say, launch an offensive. Send in your platoon. 30-50 men should be ample sufficient for a small support center. M16's, grenades, everything. Pretty sure the support script the guy was reading is not going to provide him the "next step to follow" in this situation. He'll have no choice but to find you a laptop on the spot.
One 10-20W Intel IGP: ~$20.
Two 130W quad-core Core i7 920 processors: $568
Using the latter to barely manage to match the performance of the first: priceless.
Remind me to short MSFT when the market opens tomorrow morning.
It's because you are confusing quickness with rapidness. See this drive has a quickness about 3.5x better than regular drives, but a 10x higher rapidness ! They also improved the speediness by about 5x.
Hopes that clears it up for you.
Even more freaky: got any hair from an epyptian pharaoh ? Christopher Columbus ? Julius Caesar ? Let's clone them !
Yes: when they started, they had ZERO server and a non-existent market cap. It was cost effective for them to do so. And it still is.
Of course you can. The lack of technical details in your post proves you have no idea what it takes to build servers comparable to what storage vendors sell, and what is exactly the value that they offer when you buy these at over $1200/TB.
Take a concrete example: Thumper X4540. Sun use the same Opteron 2300 series processors you can buy on newegg. They use the same nVidia chipsets MCP55 and IO55 you find on many motherboards from newegg. They use the same LSI SAS 1068e chips you can find on the Supermicro card AOC-USAS-L8i recommended by Sun ZFS engineers themselves. They use the same enterprise-class SATA drives (Seagate IIRC) you can buy from newegg. They use DDR2 modules based on the same OEM RAM chips used by many memory vendors selling on newegg. And all the technology is the same: same PCI-E links, same 10GbE technology, same SATA links, etc. The only major custom-designed electronic component in the X4540 is the motherboard (mostly because they had to connect the 3 PCI-E slots to an IO55 chipset linked to an independent HT link because the sequential throughput of the 48 disks already use about 70% of the throughput of the two other 2000MT/s HT links: 48 * 120 MB/s / (2 * 4000 MB/s) = 0.72). But this custom motherboard is a pretty much unique requirement for the X4540 -- 99% of the storage servers on the market are far from being able to saturate 2 HT links as almost nobody else packs 48 drives in 4U.
The value of what Sun sells is twofold. They validate the platform as a whole: compatibility of the components, thermal/power characteristics, basic assessment of the failure rate of components, etc (something you may not know how to do, but system integrators such as me have been doing for years successfully). And they offer a bunch of "enterprise" features that are irrelevant to this discussion about performance and reliability of the I/O subsystem (mechanical design of the chassis, drive bays, IPMI and other monitoring features, etc).
This myth that storage vendors have access to "superior" technology has to stop. As always, I'll conclude by citing the example of Google that started by building their datacenters out of OEM parts with motherboards and drives literally velcro'd together. Perfect example of good system integrators hired to do the job in-house instead of buying from storage vendors...
It's funny how this viewpoint is always the one promoted on slashdot. One could argue that the Linux GPL is the problem. FreeBSD and Mac OS X had no problem integrating ZFS into their code precisely because the ZFS license (CDDL) allowed it.
You know your "x% of the Sun price" comment makes me think that no storage vendor offers anything between the $120/TB and $750/TB range. Disks sell for $120/TB raw; DIY solutions (counting the PC hardware) can be doable around $200-250/TB; and the less expensive offerings from storage vendors always sell above the $750/TB mark. Something tells me a storage startup targetting the $300-500/TB range would be very, very successful...
An additional 48GB of RAM and 18GB of SSD are not worth $50k. Seriously... Registered ECC DDR2 RAM is about $50/GB and SSD about $20/GB (gross overestimation): they are really worth 48*50 + 18*20 = $2760... Sun is charging 18x more !
Also the 7210 with 48x250GB is strictly equivalent to the X4540 with 48x250GB (same amount of RAM, no SSD), but is $13k more expensive... for the same box ! That is outrageous.
The X4540 is even better to prove your point as it is cheaper than the X4500:
12TB (48x250GB) - $21,995.00
and is virtually identical to the new 7210 box (config with 48x250GB) that sells for $34,995.00. Therefore proving that the same hardware is sold at a 60% markup ! Someone mod the parent up, he laid out the perfect counter-argument to the GP.
Absolutely. The storage industry has always been a particularly profitable market precisely because buyers think these prices are justified. IMHO it's caused by a lack of competition in the high-end market (competiton is much more fierce in the entry-level and mid-range market). As someone pointed out, Google built a highly reliable platform and is certaintly not paying $10k/TB. Read about Google FS.
A friend of mine who works for a storage vendor that should remain nameless fully admits that they can sell some systems at 4-5x their OEM prices only because their customers, like you, think that "it must be worth it".
Look at the diff between config #2 ($35k, 32GB RAM) and #3 ($42k, 64GB RAM) of the Sun Thumper x4540 (48 drives in 4U): http://shop.sun.com/is-bin/INTERSHOP.enfinity/WFS/Sun_NorthAmerica-Sun_Store_US-Site/en_US/-/USD/ViewStandardCatalog-Browse?CategoryName=SF_X4540&CategoryDomainName=Sun_NorthAmerica-Sun_Store_US-SunCatalog Sun charges $7000 for an additional 32 GB of DDR2 registered ECC RAM, when in reality an increase from 32 GB to 64 GB should only costs 64 GB * $46/GB (price for 4GB modules) - 32 * $20/GB (price for 2GB modules) = $2304. So Sun is charging 3x the OEM price for a RAM upgrade. (Before you ask, I know the prices off the top of my head because I recently built a box with 32GB RAM).
Look at, as pointed out by another poster, the diff between a Thumper x4540 with 48 x 250GB SATA drives at $22k and a Sun Storage 7210 with 48 x 250GB SATA drives at $35k. This is a $13k price difference for virtually the same box. Beside even the x4540 is overpriced (another friend of mine bought one with the smallest drives and replaced them with 1TB from Dell to end up saving $20k to his employer).
So, no this practice of overpricing in the storage industry is not justified ! I have been saving tens of thousand of dollars by buying and building my own servers from newegg and literally "throwing a few drives in 2U chassis" (and throwing ZFS on top of it) and guess what ? It works pretty well ! Obviously not everybody can do it (don't build your servers if you don't know the diff between 1.8V and 2.0V RAM, or the effect of a 75W vs. 120W processor in a 1U chassis, etc), but if you can do it, you will save non-negligible amounts of money to your employer. This is important both for small startups who have to run as efficiently as possible, as well as Fortune500 like Google who have to scale efficiently. But sure, if you have the money and don't mind getting ripped off by storage vendors, go ahead, it's your money :) I don't deny they sell high-quality hardware, it's just unnecessarily expensive.
Only the highest-end processor, Core i7 965 Extreme Edition, supports QPI at 6.4 GT/s. The 920 and 940 support only 4.8 GT/s. So the amount of bandwidth on a QPI link is:
This is comparable to the HyperTransport bandwith of a Phenom processor (4.0 GT/s), which AMD is supposed to scale to 5.2 GT/s in the near future IIRC:
No, the UltraSPARC T2 was released in October 2007.
Correct.
Incorrect. The GP described a second preimage attack. Three main types of attacks exist against hash function. In order of increasing complexity:
Your datapoint is irrelevant. Because today's processors are much faster and because the cipher implementations have been improved, it is now much less costlier to encrypt data. Here are some "openssl speed" benchmarks of the RC4 symmetric cipher on a current processor and one released 8 years ago with a version of OpenSSL almost as old:
This is a 17x improvement in performance ! Run the quad-core processor in 64-bit mode and it would probably be 20x faster. By comparison, disk throughput has increased by only about 2x over the last 8 years (50 MB/s vs. 100 MB/s). So run the same test today but replace your 8 Xeon 800 MHz with 8 quad-core processors with 12 disks and you should see almost no speed decrease caused by a well-designed disk encryption app (I can vouch for dm-crypt).
Seriously why does everybody seem to care that much about taxes ? The tax differences between McCain's plain and Obama's plan will not amount to more than a few hundred bucks per year for the average taxpayer. Care about how the next president is going to run the country, economy, healthcare, international relations, not about a few hundred bucks.
This is false. Case in point: the first MD5 collision announced by Wang and his team in 2004 affected 2 data blocks of the same size. More generally, all cryptographically secure hashing algorithms are designed to output a hash as random as possible, no matter what the input size is.
I was trying to be funny. I agree a 1 sentence description would have been better.
The words "Golomb ruler" are displayed in a dark green color by your browser. Placing the mouse pointer over them usually transforms it in a hand. This is called an "hyperlink", or more commonly, "link". By clicking on it, you are redirected to a page from a site called "Wikipedia", a free, multilingual online encyclopedia project. This page explains what a Golomb ruler is. HTH.
What is this ? The quantum operator for 'different and equal' ?