You can't go by brand alone - at some point every manufacturer has had a line of bad drives.
StorageReview has a Drive Reliability Survey that lists statistics for many drive families. For example, WD 205Bx drives are near the top of the rankings (99th percentile) while the 600Ax is near the bottom (10th percentile).
Has anyone tried to use IP multicasting for this sort of software distribution? It seems like it would offer a significant saving in bandwidth costs, because the server would only be transmitting one copy of the data at a time. The technical challenges (file reassembly, lost packets, authentication, etc) shouldn't be too hard to solve, and an application like this might encourage ISPs to provide better multicast routing.
"Transparent Alumina" in the form of Optical Sapphire has been widely available for years. See, for example, Edmund Optics. It's also used in high-end wristwatches.
But a black hole is not a physical object, it's an abstraction. The radius of a blackhole is defined as the distance where the escape velocity equals lightspeed. And that distance is directly proportional to the black hole mass, hence the 2x radius increase.
Once a star has collapsed into a black hole, you shouldn't use "radius" to describe it. Because of the way that space is curved inside a black hole, the distance from the central singularity to the event horizon is not a well-defined quantity (and is impossible to actually measure).
Instead you should talk about the circumference of the event horizon, which can be measured from outside the black hole, and which is also directly proportional to the mass.
Remember that "Circumference = 2*pi*radius" is only true for flat geometries.
another benefit of his low-cost space travel agenda would be to mine H3 from the moon, where it exists in copious supply. Somehow (i'm no chemist) this H3 could be broken down into H2 and used for fuel-cell cars and those city buses in Chicago. Anyone have comments on this?
You're confusing two concepts. "H3" refers to Helium-3, a rare isotope with 2 protons and 1 neutron. Its value is that it could be used in nuclear fusion reactors, not fuel cells. You could use the electricity from these fusion reactors to produce hydrogen, but there's no direct connection.
There are some nice-looking battery-backed RAM cards here, but I've never used them and don't know how much they cost. Available in capacities of 128M to 1G, with two redundant Li-ion batteries and a 64-bit PCI interface.
My question is simple, now that disks are IDE, have lots of heads and even worse differing Heads/Cylander/Sector translation scemes is this type of system even possible?
I wouldn't say that disks have lots of heads - 2 to 4 is probably typical, and there are models that only have 1 (e.g. Maxtor "Fireball 3" series).
Don't pay any attention to the BIOS geometry that claims 16 heads - those numbers are pure fiction. In fact the whole concept of the C/H/S geometry is obsolete. It assumes that the number of sectors per track is constant, when in fact it varies. Outer tracks have a larger circumference, so they can hold more sectors. A drive might have 30 different zones, each with a different number of sectors per track.
Tools like "zcav" (bundled with the "bonnie++" benchmark utility) will show this quite clearly, because the sustained transfer rate of a disk is proportional to the number of sectors per track. The rotation rate is constant, so more sectors-per-track means more sectors-per-second passing under the head.
Drives tend not to expose the information you need to translate logical block addresses into physical locations. Apart from the zones, you also have the problem of re-mapped sectors (where a spare physical sector is substitued at the logical address of a failed one).
p.s. "drivers/block/elevator.c" in the Linux kernel might be of interest.
Right, or we could, you know, fix the hole in the ozone layer.
The fundamental problem[1] with the ozone layer is not a lack of ozone. Ozone is created when high-energy UV interacts with oxygen, and eventually reaches an equilibrium concentration where the rate of production equals the rate of destruction.
The "ozone hole" is a result of other chemical reactions that reduce the equilibrium O3:O2 ratio. As long as those other chemicals are present, it wouldn't do much good to dump additional ozone into the upper atmosphere.
[1] Assuming there is really a problem, and it wasn't just a convenient excuse to get CFCs off the market once their patent protection had expired.
Why don't these companies pay for the onscreen guide via advertising?
I have an RCA TV with Guide+, and it does have provisions for advertising. There are two ad boxes on the left-hand side of the page, but happily most of the time these are blank ("happily" because the ads slow down the screen redraw speed significantly). I've also seen text ads inserted in-line in the program listing section.
IANANP either, so someone please explain just what "depleted uranium" is. If it's depleted, then it isn't uranium anymore, is it?
It refers to the amount of the isotope with atomic weight 235. "Natural" uranium is mostly the 238 isotope, with (IIRC) about.07% of 235.
"Enriched" uranium has a higher ratio of U235, and "depleted" has a lower ratio. Weapons and some power plant designs require enriched uranium because it has different fission characteristics (e.g. the probability that a neutron will cause the nucleus to split).
Enriched, natural, and depleted uranium are chemically the same; plutonium is different.
Anyway, can't you make the BIOS appear as a device under/dev like everything else?
On the Netwinder platform (StrongARM-based Linux computer) there was a kernel module that provided a/dev/nwflash device, and a userspace program to update the BIOS using that interface. I don't know if there's an x86 equivalent.
...a setup that would allow me to put my computer 20-30 feet away in another room, but still have the things I need in front of me.
The Avocent (formerly Cybex) "LongView" will give you remote keyboard/video/mouse/audio/RS-232 over a single CAT5 cable. I've only used them with NT servers, so I'm not sure how the video quality would be for gaming (although the "3D Pipes" screensavers always looked fine).
The Icron USB Ranger claims to be a 4-port 100-metre USB (1.1) extender, also over a CAT5. You could use this for your floppy and CD burner.
Near surface natural CO2 deposits (dry ice) have been discovered and found to be a huge danger to anything that comes around
Are you sure that those were CO2 deposits, and not methane hydrates?
I've never heard of undersea dry ice, although there are a few lakes like Lake Nyos that contain very large amounts of dissolved CO2, and have occasionally released large clouds of the gas (killing hundreds of people in the valley below).
Not in my case - the 'dmesg' showed lots of IDE errors and bus-resets, and the Maxtor diagnostic (before I ran the zero-fill utility) conceded that the drive was defective.
Still, that's an interesting point about the bad memory.
Well, I just had a Maxtor 80G eat a chunk of my data about a week ago (luckily it hit/usr and not/home), so I don't know if they really are any more reliable.
I don't know if I'd be eligible for any warranty-replacement, because (A) I didn't buy this drive directly, but got it from a liquidated dot-com and (B) now that I've run it through their zero-fill utility it's reporting that my "drive is certified error-free" again.
p.s. Does anyone know how to get a Maxtor, or any other ATA drive, to print out a "grown defect list" or some other indication of how many sectors have gone bad and been re-mapped? The closest I've found so far is a SMART attribute, but it's normalized to a 0-253 range with no obvious way to translate back to real numbers.
After reading the benchmarks comparing ReiserFS and ext3 mounted with 'data=ordered' and 'data=writeback', I decided to try writeback mode. [...] An image I had been working on and saved had been replaced by the content of several e-mail messages. rxvt would no longer start correctly from the KDE panel, even though checking through the properties it looked okay.
Um, yes, that's what Writeback does. From the mount(8) manpage:
Data ordering is not preserved - data may be written into the main file system after its metadata has been committed to the journal. This is rumoured to be the highest-throughput option. It guarantees internal file system integrity, however it can allow old data to appear in files after a crash and journal recovery.
BTW, I've had the same thing happen to me on Reiserfs.
Take a look at OProfile. It's quite a nice tool, although it's not a direct replacement for gprof. From their 'About' page:
OProfile is a system-wide profiler for Linux x86 systems, capable of profiling all running code at low overhead. OProfile is released under the GNU GPL.
It consists of a kernel module and a daemon for collecting sample data, and several post-profiling tools for turning data into information.
OProfile leverages the hardware performance counters of the CPU to enable profiling of a wide variety of interesting statistics, which can also be used for basic time-spent profiling. All code is profiled: hardware and software interrupt handlers, kernel modules, the kernel, shared libraries, and applications (the only exception being the oprofile interrupt handler itself).
Not quite the case. The camcorder doesn't emit infrared light, it just receives them that are emitted from the target, or anything with heat.
Got a reference to support this? It seems unlikely.
Remember that the label "infrared" covers a large chunk of the spectrum.. The type used in remote controls, camera auto-focus, etc is just below the visible spectrum. It behaves like visible light, and can be detected with the same sensors (try pointing a TV remote at a camcorder some time; you'll probably be able to see the IR LED flashing).
A person would have to be on fire to be emitting much infrared at these frequencies. Cameras designed to operate in this range normally have a ring of IR LEDs around the lens, or come with a similar light source.
Those "heat vision" cameras are operating at significantly lower frequencies of "infrared", and tend to require more exotic components (e.g. chilled sensors, or lenses made out of germanium).
Thirdly, you can't possibly be suggesting that a drive that fails when you put something that isn't a CD in it is a defective drive?? What's your standard these days, that the product must never, ever fail under any circumstances? I mean, Christ! Did you actually say class-action lawsuit? What planet are you on?
I'm damn well suggesting that a drive shouldn't fail when you put in something that is PHYSICALLY COMPATIBLE with a CD. Sure, I don't expect it to be able to handle a cheese sandwich or a sanding disc, but a correctly-sized piece of plastic should be fine.
As another poster suggested, if it's not logically compatible with what the drive is expecting, then the drive should either eject it or ignore it. It should *not* crash, and it should (*not*)^2 corrupt any firmware or do anything that can't be cured by a cold reboot.
I've had scratched audio CDs (being played as audio CDs, not being ripped) cause my computer to hang, because the drive did evil things to the IDE bus. That's just crappy engineering, like those "shopping cart" websites that read prices from a user-submitted form, or blindly pass user input to an SMTP client without stripping out escape sequences. In the real world, programs and devices need to perform sanity checks on their input, and fail properly when they're fed junk. The only reason we let the firmware people get away with it is that it's very hard to examine their code.
Uh, if you usually go to Comdex and you haven't noticed any other LUGs, why would you want to emulate their "methods and focuses"?
There's more than one "Comdex". VanLUG was at the one in Vancouver, BC, Canada last month. Other LUGs might have experiences from some of the other Comdex venues (Chicago, Las Vegas, Atlanta, etc).
Slashdot Mirror
The hardware requirements page suggests that it does:
SuSE Linux comes with drivers for common cards including the following:
ATI: Radeon 9000/9500/9700
nVidia: GeForce 4, GeForce FX
Matrox: G450/G550
I have an 8500DV, which also works (though I haven't tried the special features like video-capture or firewire yet).
You can't go by brand alone - at some point every manufacturer has had a line of bad drives.
StorageReview has a Drive Reliability Survey that lists statistics for many drive families. For example, WD 205Bx drives are near the top of the rankings (99th percentile) while the 600Ax is near the bottom (10th percentile).
Has anyone tried to use IP multicasting for this sort of software distribution? It seems like it would offer a significant saving in bandwidth costs, because the server would only be transmitting one copy of the data at a time. The technical challenges (file reassembly, lost packets, authentication, etc) shouldn't be too hard to solve, and an application like this might encourage ISPs to provide better multicast routing.
"Transparent Alumina" in the form of Optical Sapphire has been widely available for years. See, for example, Edmund Optics. It's also used in high-end wristwatches.
But a black hole is not a physical object, it's an abstraction. The radius of a blackhole is defined as the distance where the escape velocity equals lightspeed. And that distance is directly proportional to the black hole mass, hence the 2x radius increase.
Once a star has collapsed into a black hole, you shouldn't use "radius" to describe it. Because of the way that space is curved inside a black hole, the distance from the central singularity to the event horizon is not a well-defined quantity (and is impossible to actually measure).
Instead you should talk about the circumference of the event horizon, which can be measured from outside the black hole, and which is also directly proportional to the mass.
Remember that "Circumference = 2*pi*radius" is only true for flat geometries.
At least in Debian, even with "linux single" you have to type the root password to get root.
How about with "linux init=/bin/sh"?
another benefit of his low-cost space travel agenda would be to mine H3 from the moon, where it exists in copious supply. Somehow (i'm no chemist) this H3 could be broken down into H2 and used for fuel-cell cars and those city buses in Chicago. Anyone have comments on this?
You're confusing two concepts. "H3" refers to Helium-3, a rare isotope with 2 protons and 1 neutron. Its value is that it could be used in nuclear fusion reactors, not fuel cells. You could use the electricity from these fusion reactors to produce hydrogen, but there's no direct connection.
There are some nice-looking battery-backed RAM cards here, but I've never used them and don't know how much they cost. Available in capacities of 128M to 1G, with two redundant Li-ion batteries and a 64-bit PCI interface.
My question is simple, now that disks are IDE, have lots of heads and even worse differing Heads/Cylander/Sector translation scemes is this type of system even possible?
I wouldn't say that disks have lots of heads - 2 to 4 is probably typical, and there are models that only have 1 (e.g. Maxtor "Fireball 3" series).
Don't pay any attention to the BIOS geometry that claims 16 heads - those numbers are pure fiction. In fact the whole concept of the C/H/S geometry is obsolete. It assumes that the number of sectors per track is constant, when in fact it varies. Outer tracks have a larger circumference, so they can hold more sectors. A drive might have 30 different zones, each with a different number of sectors per track.
Tools like "zcav" (bundled with the "bonnie++" benchmark utility) will show this quite clearly, because the sustained transfer rate of a disk is proportional to the number of sectors per track. The rotation rate is constant, so more sectors-per-track means more sectors-per-second passing under the head.
Drives tend not to expose the information you need to translate logical block addresses into physical locations. Apart from the zones, you also have the problem of re-mapped sectors (where a spare physical sector is substitued at the logical address of a failed one).
p.s. "drivers/block/elevator.c" in the Linux kernel might be of interest.
Right, or we could, you know, fix the hole in the ozone layer.
The fundamental problem[1] with the ozone layer is not a lack of ozone. Ozone is created when high-energy UV interacts with oxygen, and eventually reaches an equilibrium concentration where the rate of production equals the rate of destruction.
The "ozone hole" is a result of other chemical reactions that reduce the equilibrium O3:O2 ratio. As long as those other chemicals are present, it wouldn't do much good to dump additional ozone into the upper atmosphere.
[1] Assuming there is really a problem, and it wasn't just a convenient excuse to get CFCs off the market once their patent protection had expired.
Why don't these companies pay for the onscreen guide via advertising?
I have an RCA TV with Guide+, and it does have provisions for advertising. There are two ad boxes on the left-hand side of the page, but happily most of the time these are blank ("happily" because the ads slow down the screen redraw speed significantly). I've also seen text ads inserted in-line in the program listing section.
just a damn shame that in the UK, no citizen is allowed to own anything resembling a geiger counter
Yet it seems that you folks are allowed to have nuclear-powered lights (tritium+phosphor devices) that are illegal in the US / Canada. Odd laws...
IANANP either, so someone please explain just what "depleted uranium" is. If it's depleted, then it isn't uranium anymore, is it?
.07% of 235.
It refers to the amount of the isotope with atomic weight 235. "Natural" uranium is mostly the 238 isotope, with (IIRC) about
"Enriched" uranium has a higher ratio of U235, and "depleted" has a lower ratio. Weapons and some power plant designs require enriched uranium because it has different fission characteristics (e.g. the probability that a neutron will cause the nucleus to split).
Enriched, natural, and depleted uranium are chemically the same; plutonium is different.
Anyway, can't you make the BIOS appear as a device under /dev like everything else?
/dev/nwflash device, and a userspace program to update the BIOS using that interface. I don't know if there's an x86 equivalent.
On the Netwinder platform (StrongARM-based Linux computer) there was a kernel module that provided a
Also here and here.
In every nickel in your pocket, I wouldn't be surprised to find more than a trace amount of iron.
Nickel (the element) is also ferromagnetic.
The Avocent (formerly Cybex) "LongView" will give you remote keyboard/video/mouse/audio/RS-232 over a single CAT5 cable. I've only used them with NT servers, so I'm not sure how the video quality would be for gaming (although the "3D Pipes" screensavers always looked fine).
The Icron USB Ranger claims to be a 4-port 100-metre USB (1.1) extender, also over a CAT5. You could use this for your floppy and CD burner.
Near surface natural CO2 deposits (dry ice) have been discovered and found to be a huge danger to anything that comes around
Are you sure that those were CO2 deposits, and not methane hydrates?
I've never heard of undersea dry ice, although there are a few lakes like Lake Nyos that contain very large amounts of dissolved CO2, and have occasionally released large clouds of the gas (killing hundreds of people in the valley below).
Not in my case - the 'dmesg' showed lots of IDE errors and bus-resets, and the Maxtor diagnostic (before I ran the zero-fill utility) conceded that the drive was defective.
Still, that's an interesting point about the bad memory.
Well, I just had a Maxtor 80G eat a chunk of my data about a week ago (luckily it hit /usr and not /home), so I don't know if they really are any more reliable.
I don't know if I'd be eligible for any warranty-replacement, because (A) I didn't buy this drive directly, but got it from a liquidated dot-com and (B) now that I've run it through their zero-fill utility it's reporting that my "drive is certified error-free" again.
p.s. Does anyone know how to get a Maxtor, or any other ATA drive, to print out a "grown defect list" or some other indication of how many sectors have gone bad and been re-mapped? The closest I've found so far is a SMART attribute, but it's normalized to a 0-253 range with no obvious way to translate back to real numbers.
After reading the benchmarks comparing ReiserFS and ext3 mounted with 'data=ordered' and 'data=writeback', I decided to try writeback mode. [...] An image I had been working on and saved had been replaced by the content of several e-mail messages. rxvt would no longer start correctly from the KDE panel, even though checking through the properties it looked okay.
Um, yes, that's what Writeback does. From the mount(8) manpage:
Data ordering is not preserved - data may be written into the main file system after its metadata has been committed to the journal. This is rumoured to be the highest-throughput option. It guarantees internal file system integrity, however it can allow old data to appear in files after a crash and journal recovery.
BTW, I've had the same thing happen to me on Reiserfs.
Take a look at OProfile. It's quite a nice tool, although it's not a direct replacement for gprof. From their 'About' page:
OProfile is a system-wide profiler for Linux x86 systems, capable of profiling all running code at low overhead. OProfile is released under the GNU GPL.
It consists of a kernel module and a daemon for collecting sample data, and several post-profiling tools for turning data into information.
OProfile leverages the hardware performance counters of the CPU to enable profiling of a wide variety of interesting statistics, which can also be used for basic time-spent profiling. All code is profiled: hardware and software interrupt handlers, kernel modules, the kernel, shared libraries, and applications (the only exception being the oprofile interrupt handler itself).
Not quite the case. The camcorder doesn't emit infrared light, it just receives them that are emitted from the target, or anything with heat.
Got a reference to support this? It seems unlikely.
Remember that the label "infrared" covers a large chunk of the spectrum.. The type used in remote controls, camera auto-focus, etc is just below the visible spectrum. It behaves like visible light, and can be detected with the same sensors (try pointing a TV remote at a camcorder some time; you'll probably be able to see the IR LED flashing).
A person would have to be on fire to be emitting much infrared at these frequencies. Cameras designed to operate in this range normally have a ring of IR LEDs around the lens, or come with a similar light source.
Those "heat vision" cameras are operating at significantly lower frequencies of "infrared", and tend to require more exotic components (e.g. chilled sensors, or lenses made out of germanium).
Thirdly, you can't possibly be suggesting that a drive that fails when you put something that isn't a CD in it is a defective drive?? What's your standard these days, that the product must never, ever fail under any circumstances? I mean, Christ! Did you actually say class-action lawsuit? What planet are you on?
I'm damn well suggesting that a drive shouldn't fail when you put in something that is PHYSICALLY COMPATIBLE with a CD. Sure, I don't expect it to be able to handle a cheese sandwich or a sanding disc, but a correctly-sized piece of plastic should be fine.
As another poster suggested, if it's not logically compatible with what the drive is expecting, then the drive should either eject it or ignore it. It should *not* crash, and it should (*not*)^2 corrupt any firmware or do anything that can't be cured by a cold reboot.
I've had scratched audio CDs (being played as audio CDs, not being ripped) cause my computer to hang, because the drive did evil things to the IDE bus. That's just crappy engineering, like those "shopping cart" websites that read prices from a user-submitted form, or blindly pass user input to an SMTP client without stripping out escape sequences. In the real world, programs and devices need to perform sanity checks on their input, and fail properly when they're fed junk. The only reason we let the firmware people get away with it is that it's very hard to examine their code.
Uh, if you usually go to Comdex and you haven't noticed any other LUGs, why would you want to emulate their "methods and focuses"?
There's more than one "Comdex". VanLUG was at the one in Vancouver, BC, Canada last month. Other LUGs might have experiences from some of the other Comdex venues (Chicago, Las Vegas, Atlanta, etc).