I think you are mistaken. The equation converting F to C is linear. F = C * 1.8 + 32.0. Both units are completely arbitrary. F used the freezing point of brine while C used the freezing point of pure water as a zero reference. F used the human body temperature and C used the boiling point of pure water as the 100 reference. Arbitrary.
btrfs sounds very interesting. It was not ready for prime time when I setup my current box, which is why I chose zfs instead. I'll have to try to murder it in a VM:)
Can you set btrfs to use arbitrary block devices or files? One of the things that made it easy to screw with zfs was it's ability to do so. I was able to set up a VM and do random writes to the "drives" it was using to see how it would respond. Anyway, to my surprise btrfs seems production-ready at this time so I'll have to play with it.
When I ran mdadm I would just partition the disks so that I was running multiple raid5s on each drive (so if I had 3x1TB and 2x3TB drives I'd have 6TB of usable space - 4x1TB+1x2TB).
Yes, you can do this with zfs as well, but you need to be very, very careful or you won't have the redundancy that you think you do. There are crazy partition schemes that can let you do Drobo-ish things - but they get so complicated that you need to keep track of them in something like an Excel spreadsheet.:)
Besides, zfs seems to like having the entire drive.
Unreliable SATA cables or bad drive electronics can do EXACTLY the same thing.
No, because the corruption will be caught. I - and many others - have had controller failures and bad hard drives cause corruption on the drives, but this corruption was caught during the scrub. If the data is bad in-memory and then hashed and written to disk in that condition, the corruption will be silent.
Even ECC RAM has a finite undetected bit error rate.
ECC RAM will only correct 1 bad bit, but the system is supposed to halt on 2 bad bits. A halt is better than operating in an unknown state, IMHO.
Obviously ECC RAM is a Good Idea when you have Important Data, no matter what the file system is, but there is absolutely nothing magic about ZFS that makes magically higher demands on RAM.
Even if you aren't worried about the specific scenario where the whole pool goes down, taking all the trouble to run a filesystem with parity seems silly if you can't trust the error detection/correction to actually work. And since you are writing a hash as well as a file, you are doubling the opportunities to corrupt any particular file vs a regular file system.
Not something I would attempt. Personally, I accept this limitation and always add drives in pairs. Upgrading capacity then becomes a 2-drive cost instead of a number_of_disks_in_raid cost.
then there is no easy way to replace those with 5 3TB drives one at a time and actually get use out of the extra space.
It's not THAT bad. You do this: 1. Put new disk in usb cradle. 2. Run 'zpool replace', swapping new disk for old disk. 3. Take the new disk and physically replace the old disk. 4. Repeat 1-3 for each new disk until you have the whole array running at the new capacity. 5. If autoexpand is not enabled, run the 'zfs online' command with the '-e' flag to use the new capacity.
I've only used FreeBSD, not Linux - but I presume this would work so long as you are giving ZFS the whole disk. ZFS does not care which interface disks are attached to... you can take them all out and shuffle them around and it will map them correctly.
I've been a member of the Church of Parity ever since I discovered that some of my dutifully backed-up family photos had not only gotten corrupted, but the backup dutifully copied the corruption as well. Ever since, I use backup tools which do a parity check (e.g. Unison) and I try to store important things on ZFS if I can.
In my case I was lucky and I had an older backup without the corruption. But lesson learned... Also, have more than one backup:)
ZFS is in the middle, more easily expandable than some, but definitely not as good as the easiest.
Yes, ZFS is not a Drobo. You need to plan out your disk usage from the beginning, because you are kind of stuck with it.
For instance, if you have 5 disks and they are all the same size and you want 2 disk redundancy, it is almost a no-brainer to setup a raidz2. The downside is that if you ever want to make the vdev larger by replacing disks, you need to replace all 5 disks to the new larger size... a vdev is limited by the smallest disk. You can mitigate this by putting the same 5 disks into a pair of mirrors plus a hot spare. You will lose some initial capacity, but then later on you can add capacity by swapping out just two disks or by adding another pair to the pool.
And once you've added a vdev to the pool, you can never remove it... that's probably the biggest irritation for me personally. Even that isn't such a big deal, since it is so easy to clone the whole pool to another one.
I guess I risk getting into a semantic argument, so I should just stop. From my perspective, the iPod itself never dropped in price but they did add less-capable models at lower price points. You are probably right from your perspective - something with the capabilities of the currently-offered watch will certainly be available at a lower cost, but there will always be a $350-ish model as well.
I know that Volvos have largely been displaced by the Prius in the, "Oh, God, I'm stuck behind X," department - but I'll never be able to shake the years of conditioning from getting stuck behind some boxy 7xx series floating along at or under the speed limit.
Most people who can afford a nice watch already own one. So to justify its cost, it would need to be worth as much as its purchase price plus the cost of the nice watch you'll no longer be using.
I disagree. I don't think their target market is necessarily "people who like to wear an expensive watch". I think they are hoping to attract people who don't necessarily wear watches, or when they do it is for a specific purpose (e.g. jogging, swimming, etc). Apple will always choose profit margin over market share, so I don't think they really care too much if the price is high - but the product has to be compelling and I'm contending that it is not except to some excruciatingly small niche markets.
In other words, don't think "would I buy this for $350"? The answer is likely to be "no" for you and most people. The question is, "Would I use this if it were free?" If the answer is "yes", then it becomes a marketing and pricing exercise - something that neither of us is equipped to debate. If the answer is "no" then the product is dead.
Then, they release a second-generation product at a third the price
I don't think Apple generally reduces prices. Usually they keep the price and margin steady but improve the hardware.
As one of the few people on Slashdot who still wears a watch, I'd definitely use one
So then there may be hope for this product, because somewhere out there is a richer/foolhardier version of yourself who thinks of $350 just like you think of $100.
Then I'd argue that it is too early to sell it. The iPod was useful on day 1. So was the iPhone, and for that matter the PowerBook. Even the iPad was awesome on day 1. This comes out and, cool as it may be, I can't think of very many uses for it that aren't exceedingly niche.
LOL, true. We were talking about this at work. I'm far from an Apple hater. I bought a first-gen iPod and loved it, along with some later generations. I've had two iPhones (though now am on my second Android). I'm on my 4th Mac. I have Kindle tablets but admit that the iPad is a very nice machine.
With that said, it is hard for me to imagine why I would want - price aside - another device on my wrist that does a subset of the thing in my pocket. If the watch were useful away from the phone, I could see some applications. But as is? The uses are contrived and niche.
You also have the right to go 25 down a 35MPH single-lane road, never pulling to the side to let faster traffic overtake you. That does make you a bit of a dick, though.
Why does his company need a huge pile of tax breaks to succeed? If I open a company tomorrow, how can I get away with not paying taxes?
Offer to open a factory and let localities knock themselves out trying to woo you. This is not unique to Tesla.
Why are Tesla's debt bonds in Junk status but he continues to get freebies from states?
It is junk because the business has a lot of risks, not because the business plan is fundamentally unsound. Bonds are rated according to risk. In the long run the riskier investments pay out more. Look at the stock price of Tesla if you want to see where the market thinks it is going.
Why are Tesla's cars so rudely expensive? Is there a plan for a 4 door sedan that a real family can afford in the 20K - 30K range like the Prius?
You cannot buy a battery so large at the moment for such a low cost. In part, this factory is an attempt to get some economy of scale so that the price will come down. But also remember that the margins on a luxury car are far higher than the margins on a family sedan. Toyota makes something like 20% on each Lexus that it makes, but only 10% overall (including Lexus). You would be nuts (or very, very confident) to enter the sub-10% market with a new product. Tesla may very well enter the low-end market some day, but I wouldn't hold my breath. For now, think of them as Audi, BMW, or Mercedes.
Why are guys who run factories employing tons of US citizens in US based factories (like Toyota) who produce super reliable product with great mileage get slapped by the media when a bogus story about a gas pedal getting stuck?
Are you kidding? Just wait until Tesla slips up. They will eventually, and the media will jump all over them. The only thing that the media loves more than an underdog is the story of a fallen angel.
Not sure why people need a super-hero.
If you can solve that, you will change the world in a serious way. You'll put a lot of "personalities" out of business - from Obama and Putin to the gossip columnist at the Enquirer.
3.8 million priuses have been sold and cab drivers will tell you they easily go into the 300K range and even if the battery runs out the car is still useable.
Prius is not all electric. Tesla makes no hybrids. If the Prius were all electric it would probably cost another $10k, or it would have to downsize like the Leaf.
But instead we continue to give money to the cartoon guy.
I'm not sure why you are picking on Tesla. We give tons of tax breaks to Toyota. Google for "Toyota Plano tax breaks" to see about their new headquarters. Hell, the Prius was directly subsidized for years through the same federal tax credit as the Teslas. Nissan and Mitsubishi get the exact same tax credit as the Tesla.
If it is any consolation, I have two Toyotas and they have been recalled for engine fires, window switch fires, sticking gas pedals, floor mats, spare tires that fall out of the bottom of the car (two times so far), and shift lever malfunction - off the top of my head. I don't think it is an exaggeration for me to say that they do some kind of recall work on at least one of the two cars every time I go in for the 6 month service. I think modern cars are very complicated and the bar for a recall is far lower than it was in the past.
Slashdot Mirror
I think you are mistaken. The equation converting F to C is linear. F = C * 1.8 + 32.0. Both units are completely arbitrary. F used the freezing point of brine while C used the freezing point of pure water as a zero reference. F used the human body temperature and C used the boiling point of pure water as the 100 reference. Arbitrary.
0 degrees F is the triple point of seawater, which is a lot more common than pure water.
100 degrees F is the human body temperature.
Still having trouble?
btrfs sounds very interesting. It was not ready for prime time when I setup my current box, which is why I chose zfs instead. I'll have to try to murder it in a VM :)
Can you set btrfs to use arbitrary block devices or files? One of the things that made it easy to screw with zfs was it's ability to do so. I was able to set up a VM and do random writes to the "drives" it was using to see how it would respond. Anyway, to my surprise btrfs seems production-ready at this time so I'll have to play with it.
When I ran mdadm I would just partition the disks so that I was running multiple raid5s on each drive (so if I had 3x1TB and 2x3TB drives I'd have 6TB of usable space - 4x1TB+1x2TB).
Yes, you can do this with zfs as well, but you need to be very, very careful or you won't have the redundancy that you think you do. There are crazy partition schemes that can let you do Drobo-ish things - but they get so complicated that you need to keep track of them in something like an Excel spreadsheet. :)
Besides, zfs seems to like having the entire drive.
I'd love for you to be right, but you haven't added any information to the discussion so it is hard to believe you.
Unreliable SATA cables or bad drive electronics can do EXACTLY the same thing.
No, because the corruption will be caught. I - and many others - have had controller failures and bad hard drives cause corruption on the drives, but this corruption was caught during the scrub. If the data is bad in-memory and then hashed and written to disk in that condition, the corruption will be silent.
Even ECC RAM has a finite undetected bit error rate.
ECC RAM will only correct 1 bad bit, but the system is supposed to halt on 2 bad bits. A halt is better than operating in an unknown state, IMHO.
Obviously ECC RAM is a Good Idea when you have Important Data, no matter what the file system is, but there is absolutely nothing magic about ZFS that makes magically higher demands on RAM.
Even if you aren't worried about the specific scenario where the whole pool goes down, taking all the trouble to run a filesystem with parity seems silly if you can't trust the error detection/correction to actually work. And since you are writing a hash as well as a file, you are doubling the opportunities to corrupt any particular file vs a regular file system.
I'd suggest some further reading.
Not something I would attempt. Personally, I accept this limitation and always add drives in pairs. Upgrading capacity then becomes a 2-drive cost instead of a number_of_disks_in_raid cost.
then there is no easy way to replace those with 5 3TB drives one at a time and actually get use out of the extra space.
It's not THAT bad. You do this:
1. Put new disk in usb cradle.
2. Run 'zpool replace', swapping new disk for old disk.
3. Take the new disk and physically replace the old disk.
4. Repeat 1-3 for each new disk until you have the whole array running at the new capacity.
5. If autoexpand is not enabled, run the 'zfs online' command with the '-e' flag to use the new capacity.
I've only used FreeBSD, not Linux - but I presume this would work so long as you are giving ZFS the whole disk. ZFS does not care which interface disks are attached to... you can take them all out and shuffle them around and it will map them correctly.
I've been a member of the Church of Parity ever since I discovered that some of my dutifully backed-up family photos had not only gotten corrupted, but the backup dutifully copied the corruption as well. Ever since, I use backup tools which do a parity check (e.g. Unison) and I try to store important things on ZFS if I can.
In my case I was lucky and I had an older backup without the corruption. But lesson learned... Also, have more than one backup :)
ZFS is in the middle, more easily expandable than some, but definitely not as good as the easiest.
Yes, ZFS is not a Drobo. You need to plan out your disk usage from the beginning, because you are kind of stuck with it.
For instance, if you have 5 disks and they are all the same size and you want 2 disk redundancy, it is almost a no-brainer to setup a raidz2. The downside is that if you ever want to make the vdev larger by replacing disks, you need to replace all 5 disks to the new larger size... a vdev is limited by the smallest disk. You can mitigate this by putting the same 5 disks into a pair of mirrors plus a hot spare. You will lose some initial capacity, but then later on you can add capacity by swapping out just two disks or by adding another pair to the pool.
And once you've added a vdev to the pool, you can never remove it... that's probably the biggest irritation for me personally. Even that isn't such a big deal, since it is so easy to clone the whole pool to another one.
If you decide to chance it, make sure you don't use the "scrub" functionality on ZFS. Scrub can cause memory errors to eat your pool like a cancer.
Or, just use ECC :)
There is "free as in beer" (usually both GPL and BSD). There is "free as in freedom" (BSD). And then there is "free as in free-range chickens" (GPL).
I would add to you "cons" list that it requires* ECC RAM, though you should probably be using that anyway.
* It's not technically a requirement, but you'll probably be sorry if you don't use it.
I guess I risk getting into a semantic argument, so I should just stop. From my perspective, the iPod itself never dropped in price but they did add less-capable models at lower price points. You are probably right from your perspective - something with the capabilities of the currently-offered watch will certainly be available at a lower cost, but there will always be a $350-ish model as well.
I know that Volvos have largely been displaced by the Prius in the, "Oh, God, I'm stuck behind X," department - but I'll never be able to shake the years of conditioning from getting stuck behind some boxy 7xx series floating along at or under the speed limit.
Most people who can afford a nice watch already own one. So to justify its cost, it would need to be worth as much as its purchase price plus the cost of the nice watch you'll no longer be using.
I disagree. I don't think their target market is necessarily "people who like to wear an expensive watch". I think they are hoping to attract people who don't necessarily wear watches, or when they do it is for a specific purpose (e.g. jogging, swimming, etc). Apple will always choose profit margin over market share, so I don't think they really care too much if the price is high - but the product has to be compelling and I'm contending that it is not except to some excruciatingly small niche markets.
In other words, don't think "would I buy this for $350"? The answer is likely to be "no" for you and most people. The question is, "Would I use this if it were free?" If the answer is "yes", then it becomes a marketing and pricing exercise - something that neither of us is equipped to debate. If the answer is "no" then the product is dead.
Then, they release a second-generation product at a third the price
I don't think Apple generally reduces prices. Usually they keep the price and margin steady but improve the hardware.
As one of the few people on Slashdot who still wears a watch, I'd definitely use one
So then there may be hope for this product, because somewhere out there is a richer/foolhardier version of yourself who thinks of $350 just like you think of $100.
It's too early to dismiss it's usefullness
Then I'd argue that it is too early to sell it. The iPod was useful on day 1. So was the iPhone, and for that matter the PowerBook. Even the iPad was awesome on day 1. This comes out and, cool as it may be, I can't think of very many uses for it that aren't exceedingly niche.
One that I would like is for it to simply buzz my wrist when I get a call.
Here you go, and only 1/7 the price.
No one wears watches for functionality any more,
Someone doesn't have a very active lifestyle.
I could see dropping 100 bucks, maybe, on something that tracks health telemetry,
If price is the only hurdle, then Apple will be fine. Your line of $100 is someone else's line at $350.
But I'm not sure I'd bother wearing it after the first few days even if it was given to me. That is a bigger problem than "too expensive".
LOL, true. We were talking about this at work. I'm far from an Apple hater. I bought a first-gen iPod and loved it, along with some later generations. I've had two iPhones (though now am on my second Android). I'm on my 4th Mac. I have Kindle tablets but admit that the iPad is a very nice machine.
With that said, it is hard for me to imagine why I would want - price aside - another device on my wrist that does a subset of the thing in my pocket. If the watch were useful away from the phone, I could see some applications. But as is? The uses are contrived and niche.
You also have the right to go 25 down a 35MPH single-lane road, never pulling to the side to let faster traffic overtake you. That does make you a bit of a dick, though.
Why does his company need a huge pile of tax breaks to succeed? If I open a company tomorrow, how can I get away with not paying taxes?
Offer to open a factory and let localities knock themselves out trying to woo you. This is not unique to Tesla.
Why are Tesla's debt bonds in Junk status but he continues to get freebies from states?
It is junk because the business has a lot of risks, not because the business plan is fundamentally unsound. Bonds are rated according to risk. In the long run the riskier investments pay out more. Look at the stock price of Tesla if you want to see where the market thinks it is going.
Why are Tesla's cars so rudely expensive? Is there a plan for a 4 door sedan that a real family can afford in the 20K - 30K range like the Prius?
You cannot buy a battery so large at the moment for such a low cost. In part, this factory is an attempt to get some economy of scale so that the price will come down. But also remember that the margins on a luxury car are far higher than the margins on a family sedan. Toyota makes something like 20% on each Lexus that it makes, but only 10% overall (including Lexus). You would be nuts (or very, very confident) to enter the sub-10% market with a new product. Tesla may very well enter the low-end market some day, but I wouldn't hold my breath. For now, think of them as Audi, BMW, or Mercedes.
Why are guys who run factories employing tons of US citizens in US based factories (like Toyota) who produce super reliable product with great mileage get slapped by the media when a bogus story about a gas pedal getting stuck?
Are you kidding? Just wait until Tesla slips up. They will eventually, and the media will jump all over them. The only thing that the media loves more than an underdog is the story of a fallen angel.
Not sure why people need a super-hero.
If you can solve that, you will change the world in a serious way. You'll put a lot of "personalities" out of business - from Obama and Putin to the gossip columnist at the Enquirer.
3.8 million priuses have been sold and cab drivers will tell you they easily go into the 300K range and even if the battery runs out the car is still useable.
Prius is not all electric. Tesla makes no hybrids. If the Prius were all electric it would probably cost another $10k, or it would have to downsize like the Leaf.
But instead we continue to give money to the cartoon guy.
I'm not sure why you are picking on Tesla. We give tons of tax breaks to Toyota. Google for "Toyota Plano tax breaks" to see about their new headquarters. Hell, the Prius was directly subsidized for years through the same federal tax credit as the Teslas. Nissan and Mitsubishi get the exact same tax credit as the Tesla.
I received a different recall notice
If it is any consolation, I have two Toyotas and they have been recalled for engine fires, window switch fires, sticking gas pedals, floor mats, spare tires that fall out of the bottom of the car (two times so far), and shift lever malfunction - off the top of my head. I don't think it is an exaggeration for me to say that they do some kind of recall work on at least one of the two cars every time I go in for the 6 month service. I think modern cars are very complicated and the bar for a recall is far lower than it was in the past.