Let's take a 64KB file, not small by any means. The fast HDDs presently do just over 200 MB/s sustained for reads. On a 7200RPM HDD the average rotational latency will be 4.17ms. Let's be conservative and say the average seek time only adds 3ms to that, although it's often higher...let's round the sum down to an even 7ms. That's 7ms before the drive starts transferring any data. At 200 MB/s and assuming the entire file is in a contiguous block on the transfer time for the 64KB file will be 312.5us. So the transfer time represents just 4.46% of the total I/O time for an HDD.
Now for that same 64KB file on an SSD. Taking an average read IOPs rate of 30K (although most SSDs are much faster), the access time (which is mostly interface overhead) comes to 33.33us. Most SSDs do well above 200 MB/s but let's keep it at 200 MB/s to help the HDD out a bit. So 33.33us access time + 312.5us transfer time = 345.83us.
HDD = 7312.5us, SSD = 345.83us.
The SSD is 21.14x times faster for a 64KB file.
An order of magnitude (1st) is defined as 10x.
That presumes that the only people who buy HDDs vs SSDs are those needing huge storage space. The price disparity between the two extends all the way down to the lower capacities, which is why most systems still ship with HDDs instead of SSDs.
Ok, how about this. The most common activity on computing devices these days is web browsing. The average, content-rich page has 100+ separate URIs. Browsers cache those resources in discrete files to make browsing faster. I'll give HDDs the benefit of the doubt and say all those files will be close enough to not require anything more than a track/head switch, thus no seek latency. The average rotational latency of a 7200RPM HDD is 4.17ms. So when a user revisits their favorite web site this means 417ms of rotational latencies to load the page of 100 cached URIs, almost a half second. Most current SSDs can do 30K random IOPs a second - many can do much higher but for the benefit of this comparison I'll say 30K, which works out to 33us per I/O. So for the web page with 100 cached URIs the total resource load time will be 3.3ms, as compared to 417ms from an HDD. That's 126x faster.
That quoted Seagate density is for SMR drives, which use overlapping tracks that are considerably slower for many I/O workloads vs traditional encoding techniques like MR/PMR, so the areal densities aren't comparable for general-use HDD applications. In other words, context does matter a great deal:)
I wasn't arguing that capacity vs performance is not a valid trade-off for applications. I was arguing about what the performance trade-off actually is (access time vs throughput for most applications).
You'll care because unless you have 20+TB of memory in your system that allows your 20+TB file to be read in its entirety without any rotational latencies then the per-I/O access time differential between an SSD and HDD will be multiplied by several million I/Os.
My point was that the performance tradeoff between SDDs and HDDs is more about random access performance (which connotes random I/O) than it is about transfer speed (which connotes sequential I/O).
The summary lists HDDs as viable vs SSDs when "high areal density is more important than ripping transfer speeds" but in most applications it's the random access time that's more useful and SSDs are better than HDDs in this regard by several orders of magnitude.
Perhaps his plan was to paint the government as coming after him on a trumped-up charge in retaliation for his raising the price of Daraprim by 5,500%. However a close look reveals he's been under investigation for quite a while, for example:
From the article:
"The new system will encode from the raw source material more intelligently, considering whether or not the material itself can really benefit from higher bit-rates, or whether identical quality can be maintained with less space and bandwidth."
I thought existing VBR algorithms already account for the absence of interframe changes by reducing the effective bit rate for those frames.
Yahoo's increase in market cap is entirely from the appreciation of Yahoo's stake in Alibaba. That would have happened even if a monkey was the CEO and conducted every board meeting by throwing his feces at the board of directors. The value of Yahoo's core business has dwindled to only $2B by recent analyst estimates.
Slashdot Mirror
Let's take a 64KB file, not small by any means. The fast HDDs presently do just over 200 MB/s sustained for reads. On a 7200RPM HDD the average rotational latency will be 4.17ms. Let's be conservative and say the average seek time only adds 3ms to that, although it's often higher...let's round the sum down to an even 7ms. That's 7ms before the drive starts transferring any data. At 200 MB/s and assuming the entire file is in a contiguous block on the transfer time for the 64KB file will be 312.5us. So the transfer time represents just 4.46% of the total I/O time for an HDD. Now for that same 64KB file on an SSD. Taking an average read IOPs rate of 30K (although most SSDs are much faster), the access time (which is mostly interface overhead) comes to 33.33us. Most SSDs do well above 200 MB/s but let's keep it at 200 MB/s to help the HDD out a bit. So 33.33us access time + 312.5us transfer time = 345.83us. HDD = 7312.5us, SSD = 345.83us. The SSD is 21.14x times faster for a 64KB file. An order of magnitude (1st) is defined as 10x.
That presumes that the only people who buy HDDs vs SSDs are those needing huge storage space. The price disparity between the two extends all the way down to the lower capacities, which is why most systems still ship with HDDs instead of SSDs.
In other words, BS.
Ok, how about this. The most common activity on computing devices these days is web browsing. The average, content-rich page has 100+ separate URIs. Browsers cache those resources in discrete files to make browsing faster. I'll give HDDs the benefit of the doubt and say all those files will be close enough to not require anything more than a track/head switch, thus no seek latency. The average rotational latency of a 7200RPM HDD is 4.17ms. So when a user revisits their favorite web site this means 417ms of rotational latencies to load the page of 100 cached URIs, almost a half second. Most current SSDs can do 30K random IOPs a second - many can do much higher but for the benefit of this comparison I'll say 30K, which works out to 33us per I/O. So for the web page with 100 cached URIs the total resource load time will be 3.3ms, as compared to 417ms from an HDD. That's 126x faster.
That quoted Seagate density is for SMR drives, which use overlapping tracks that are considerably slower for many I/O workloads vs traditional encoding techniques like MR/PMR, so the areal densities aren't comparable for general-use HDD applications. In other words, context does matter a great deal :)
I wasn't arguing that capacity vs performance is not a valid trade-off for applications. I was arguing about what the performance trade-off actually is (access time vs throughput for most applications).
You'll care because unless you have 20+TB of memory in your system that allows your 20+TB file to be read in its entirety without any rotational latencies then the per-I/O access time differential between an SSD and HDD will be multiplied by several million I/Os.
My point was that the performance tradeoff between SDDs and HDDs is more about random access performance (which connotes random I/O) than it is about transfer speed (which connotes sequential I/O).
The summary lists HDDs as viable vs SSDs when "high areal density is more important than ripping transfer speeds" but in most applications it's the random access time that's more useful and SSDs are better than HDDs in this regard by several orders of magnitude.
When the government steals they give it a nice sounding euphemism. When citizens steal they're called criminals and go to jail.
Were C-3PO and Hans Solo talking to the audience when they said that in the Empire Strikes Back and Return of the Jedi?
Backdoors are not secrets! https://www.youtube.com/watch?...
Interesting business strategy - jawboning competitors to slow down so that you can catch up. Doesn't quite work in the hypercompetitive world of tech.
Perhaps his plan was to paint the government as coming after him on a trumped-up charge in retaliation for his raising the price of Daraprim by 5,500%. However a close look reveals he's been under investigation for quite a while, for example:
http://www.cnbc.com/2015/12/17...
Maybe they'll also invent a better way to untangle corded phone cables.
https://www.quora.com/Whats-th...
Sending in an email is much easier than pulling the fire alarm.
From the article:
"The new system will encode from the raw source material more intelligently, considering whether or not the material itself can really benefit from higher bit-rates, or whether identical quality can be maintained with less space and bandwidth."
I thought existing VBR algorithms already account for the absence of interframe changes by reducing the effective bit rate for those frames.
We can't guarantee other vendors' bulbs will work so we'll cut the users' suspense and make sure they wont.
I'm a libertarian so that definitely wasn't my goal. Cruz has claimed himself to be a libertarian.
Libertarians don't call for government enforcement of minimum compensation stipulations, especially not for specific priviledged groups over others.
Looks like engineer terms to me, which is fine since most of us here are engineers.
Yahoo's increase in market cap is entirely from the appreciation of Yahoo's stake in Alibaba. That would have happened even if a monkey was the CEO and conducted every board meeting by throwing his feces at the board of directors. The value of Yahoo's core business has dwindled to only $2B by recent analyst estimates.
https://www.youtube.com/watch?...
For failing to cheat more on the CO2 emission systems. They're obviously not up to caliber of VW's NOx engineers.