And when the single point of failure in the......Cable......Controller......Drive Motor......Hermetic Seal......Whole Drive Chassis over temp... fails, what does you expenditure get you?
How do you think you're going to get two completely seperate drive/head/platter arrays in a 3.5 1 high inch form factor?
What will that do to the heat output?
How does the controller in the drive signal failure of one of the internal 'halves' using the standard protocol?
If the mirror isn't synced how do you examine each half to find the correct half to recover the data from?
Have you ever used RAID, or are we buzzwording here?
If you want that level of reliability buy premium drive mechanisms[1] and look after them.
Otherwise get back to class and stop tinkering with your Dads PC.
[1] If I say SCSI[2] I'll start a flame war, so I'll just say premium because there are other choices.
Yep, I'm sure there aren't any good reasons to sitting at home in front of a good home cinema.
And no good reasons for feeding a system capable of 800 line resolution and 6/7/8 channels of sound with a source of 200 lines and 2 fuzzy sound channels.
Guess who lost an entire Suse server in the process - ironically our databackup server, the idea being that we had the drives mirrored, and a set of three with one always being in the firesafe, cyclically syncing them every day.
Seemed a cheaper idea at the time than a tape backup - you live and learn.
Just get lots of air moving past the drive.
Don't trust SMART because you're never sure of the calibration - best to get a cheap digital thermometer from Tandy/Radio Shack (whatever you local favourite is!) and compare like with like. Tuck the probe into the cast chassis infront of the controller pcb with a bit of PVC tape so its measuring the temp of the drive chassis, but is out of the airflow.
Being a daily Reg reader, yes they may have an agenda - it does colour some of the reporting, but also a lot of UK techies read it and my understanding is after the issue was first raised they got considerable correspondance from system integrators that the failure rate was far higher in the UK then was being admitted.
The odd bias/opinion isn't unusual in news and discusion sites *cough*squishdot*cough* now is it??
The biggest mistake I've found is to put the drive in a 5.25 'cooler cage' as these enclose the drive in more metal, and vent it with a 40mm fan, which DOES NOT MOVE MUCH AIR - I remain to be convinced this helps, in my trials the temp of the drive is HIGHER in so called 'cooler bays'.
Why - look at the size of the blades on a 40mm fan, they can practically hardly cool themselves.
I've also cooked 2 Maxtors to death in a Lian-Li removable IDE Rack for similar reasons. I will never again put any 7200 rpm+ drive in a single enclosure with 40mm fans - my data is too important.
If you want to cool drives you need to move a large amount of air - ideal is one of the cages that mounts an 80mm fan with 3 drives - this will move and air and does help. Thats what we used in the RAID server I mention below, and are one of the great advantages of Chieftec cases (also sold under other names)
Failing that put the drives in the bottom so they are in front of the cases lower intake fans, or less ideal in front of the upper rear exhaust fans if you have a larger case (not great as they'll be over the PSU, but with 2 fans it will help)
Bottom line - additional 40mm fans are for decoration only, the cooling is negligable - the only case where they work are where they are built into the drives like some burners - because these draw air through the case that otherwise wouldn't move. As hard drives are hermetically sealed this doesn't count, you need to get air moving at a fair rate over the metal chassis if you want to make an impact - 'cooler bays' don't do this, they don't have the flow rate with thier puny fans, fans grills, and the fact there is very little airspace in the case. Far better just to mount it in a 5.25 mounting rails and lett convection do the rest - there will be more air flow!
The only product that ever made a difference was one that was totally open and had 3 40mm fans across the front(Bay Cooler I think??). But with 3 fans its a noisy little sucker as the 40mm run like crazy to shift enough air, I stil favour a single decent 80mm mounted at the front of a large drive cage, less noisy and more efficient.
Funny - I've always found Enermax supplies to be better than most on its regulation.
Especially when we put together an IDE RAID server with 4x8 drives on 4 3Ware cards, plus boot and CDRom drives.
So long as you have a cable with a compatible connector on each end it works.
AFAIK optical has two types, the 3.5mm jack like TOSLINK, and the squarer older type; electrical has 3.5mm jack/RCA Phono/COAX
In all cases all that is happening is that there is a bitstream of data from the transport to the DAC - so long as it fits the CD 'bitstream standard' (44.1Khz 16 Bit etc) you're home and dry
Most decent semi-pro/pro-sumer soundcards can have a daughterboard/breakout box with the same optical sockets as used on HI-FI
So you are saying that it doesn't matter what is being said, if an unelected member of the community believes that they have no right to contribute to the discussion then they can flag thier speech such that most members of the community will not be able to read what they say?
Do I need to point out that in a discussion about the evils of censoring peoples access to information how ironic your standpoint is?
And this time I choose not to post anon, to hell with it I've bugger all karma to lose.
If you transmit something via RF, anyone can listen to it.
You are physically able to receive it, and yes you can listen to it.
That does not mean it is legal.
Use of most of the RF spectrum is regulated to protect it. Internationally certain frequencies are agreed (such as GSM Frequencies, MF Ship frequencies) and the protection of these is enforced by the local Radio Communication Ageny (in UK - equivalent in your country)
Now the use of transmitting and receiving equipment is usually regulated by a licence, unless the band it works on has been derestricted.
Often it means the equipment can be freely sold, but can only be used if you are authorised.
As a holder of certification in VHF/MF Marine Bands, and SSB I have to make a (legal) commitment not to act on information I gain in course of using the equipment, and to protect the privacy of that communication.
If you think about it that is no different from a CEO not selling shares based on inside information, your ISP not using data in your plain text mail, the phone company not using information from phone calls. In all these cases legally authorised people will come across information for reasons that are legal, but are not entilted to act on it as that would be illegal. non authorised people have no right to say shin up the pole and connect a phone handset to your house wires.
Mainly I'm responding to the issues to do with RF, thats a bit off topic.
On topic of course it doesn't matter if how Reuters obtained the information, if its release to the public was not legal.
And crucially I can't see in any of the reports that Reuters gained that information via a URL - seems to me some conclusions have been leapt to. I've not seen any URL published by Reuters.
If the pdf was obtained via telnet using a password, or via SSH (call the ID code a 'key') surely that would fit the words that Intentia are using.
Remember folks - Assumption is the Mother Of All Fsck Ups.
That applies equally the/. comments as it does security...
At least I don't live the side of the pond where they patented the swing as a jok (funny) and one-click-shopping (not funny)
Mind you I guess we had a technological society going for longer, not that we are doing toooo welll these days....
Cable Select essentially auto-configures non disk devices
So your hard drive still needs to be flagged master if you want your OS to boot.
But it does mean newbies can plug a CD-ROM device in thats been delivered in CS mode, and its controller will be slave if its bundled next to a drive, master if its got the cable to itself
1. Stock IDE can Hotswap with correct cradle (kinda like SCSI can, so long as its an SCA connector), but does need controller like HighPoint that has the smarts to know whats going on.
2. Ditto Warm Swap
3. Agree
4. 80 conductor cables are limited to 40cm, and BTW are not differential as some say, they just have interleaved grounds to help cut the crosstalk.
5. Err, thats something to do with the drive, not the bus it talks over
6. Round cables are a bad idea, you destroy the whole point of the individual grounds I mentioned in point 4, the agro on the bus will cut your data throughput, and your data could be corrupting. See my other post. People like Compaq can get away with it because they know exactly what will be in the case (like no l33t cold cathode tube producing tons of EMF, and a kewl port in the side to destroy the cases EMF shielding anyway; to pick two problems from thin air)
7. Live in a part of the world that uses 50 fps PAL, trust me its better. Also no one in thier right minds uses uncompressed video when there are perfectly good broadcast standard codecs like the DV ones around. Guess you like the hard life.
8a. Agreed - thats why RAID exists - you can get better performance and/or reliablity than an individual drive unit regardless of the interface type.
8b. You mean like that internal volatile cache in your CPU, or that one in the buffer in your SCSI/IDE/MEMORY bus? The way to solve uncommitted writes is a journalling filesystem or 60USD of UPS, its not a problem of the interface.
If you don't follow the physics then trust me, I do, he knows, ditch the cables if you run faster than UltraATA33 over them if you value your data.
Use SiSoft Sandra to benchmark the drives, if they go faster at Ultra33 than at Ultra66 then you have problems. Been there, done the test with my Western Digital 80Gb/8Mb cache pair, seen the effects of nasty cable.
One CRC error will just slow the bus down, two errors in the same transmission the ATA standard won't detect and you get a corrupt byte on the disk. Finding that in the zip of l33t t00lz you had stashed away will really make your day.
Read up on all the physics nasties that happen with parrallel conductors
See my other post further up
You can't treat each pair on its own, you have to account for the electrical fields from the other conductors in the same wire, the nasty spikes from god knows what else is in the same case, and the fact that some idiot just rounded the cable and destroyed the few assmuptions you can make about immpeadance matching on the cable so you don't get nasty refelections.
But yes you can have parrallel/serial hybrids, but generally you have one or the other. Otherwise you have to cope with both techniques problems!!
Define 'SCSI' and 'IDE', there are after all many standards. I assume you mean UltraATA33/66/100/133 vs SCSI2UW/SCSI3 to compare like with like!
But both are parrallel systems, and irrespective of the largely irrelvant SCSI vs IDE pissing contest, the problem that needs to be solved is the limitations of parrallel communications.
Parrallel comms has a problem as clock speeds get higher, the immpeadance of the wires gets harder to predict, your error checking and correcting (People do know thats there right?) technology has to get smarter. The timing differences on each conductor start to get near the same order as the clock pulses and you can't figure out if that bit is in the current word or the last. Multi conductor cables are terribly sensitive to crosstalk and other interference. Basically when it comes to high clockspeeds/frequencies then parrallel technology hits limitations.
Serial technology uses less conductors, so the immpeadance of the cable is much more predictable, its also less error prone as there are no real timing issues, and the error correction is easier. You can transmit on inverted pairs and largely reject environmental noise, and with only a couple of data wires crosstalk is predictable and can be coped with. Okay it has to go 8 times as fast to get the same throughput as an 8bit parrallel, 16 times as fast for 16bit parrallel and so on, but we're getting good at fast silicon these days.
So why do we have parrallel, and why is it old tech?
Because when you are limited by the clock speed of the silicon, parrallel moves data faster. Thats why your PC/UNIX box is choc full of parrallel interfaces between devices/chips, because the limitation used to be clock speed.
Now we are reaching clock speeds where physics starts to hurt on multi conductor cables, but now we can build very fast silicon so we can exploit low conductor count cables. As a bonus they are much better at covering distances.
This is why both SCSI and IDE have solved the problem in similar ways. Serial ATA / fibreChannel SCSI (yes I know that can be optical, but its still serial transmission)
In the quest for high clock speeds, then expect to see serial interfaces becoming the norm. What protocal they are talking (SCSI/SATA/USB/IEE1394) is largely irrelevant.
I thank you, and I'll leave the fanboys in both camps to slugg it out amongst themselves...
The RAID acronym is now Redundant Array of Independant Disks
'Inexpensive' refers back to the time that build a decent sized drive that presented itself to the host as a single entity was easier with an array of small drives, because of the huge cost of larger drives.
'Independant' is more in keeping with the modern reason for build such arrays.
Re:Impossible
on
Lego Segway
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· Score: 5, Interesting
You actually think you can navigate with just your two eyes?
Yes, and I can prove it.
I sail with a friend who's inner ears were damaged by an ear infection in childhood, leaving him with no inate sense of balance. So his entire balance is now done visually.
Does it slow him up? Well he's my dads age, is an ex British Olympic Fin Class sailor, and is now blue water cruising and is an Ocean Yachmaster / Instructor.
I guess if you can cope with the heaving deck of a yacht, you can cope with anything.
The advantage of course is that motion sickness is generally caused by a conflict of 'ear' balance and 'visual' balance (for want of better terms) so he doesn't get seasick. Thats the only way I actually found out, when I mentioned in conversation that he never got sick in rough seas, you'd never ever be able to tell otherwise.
Actually the reason you get motion sickness, and those panaromic cinemas fool you into thinking you are on a roller coaster is because your eyes are very important to navigation and balance.
Of course having the two systems (ear/visual) is a very good idea evolutionary, because one compensates for the weakness in the other.
But knowing that a blind colleuge of mine doesn't fall over in a heap, and my sailing companion doesn't either, I think I can justify in saying humans can operate with only one system perfectly well
Nor are the chemicals in them a significant danger. Computer monitors, yes, contain a lot of lead. But all these other stories about the dangers of electronic waste are bullshit scare stories
You are, sir, entitled to your opinion, but I'm afraid to say the chemicals are a danger.
Look up the details on what cadmium can do to you, wonder why lithium is used for its phsycological effects in treatment of mental disorders, check out some of the chemicals used in and for the manufacturing of PCBs.
A GSM/CDMA phone is likely to be the most complicated (in terms of function versus size/power) electronic device you will ever own. Its worth 200-300UKP, and yet thanks to the marketing and lazyness they are changed each season/provider because they are heavily subsidised (at least in Europe) so the user never appreciates the true cost. Then the user whine about being stiffed for roaming...
And most galling of all is that some people just seem to feel its all right to use up and then chuck away resources. Have we learned nothing from the 'mostly harmless' chemicals in aerosols, the devastating effects of acid rain, the NOx/SOx pollution from massive consumption of fossil fuels?
Just because its cheap doesn't make it right. Slavery was very cheap, and I'm not sure that paying some poor SOB 2 USD a day to go and mine the copper/cadmium/etc for you to chuck in the skip is much better.
FYI my background is in physics and environmental sciences, and now I work for a wireless technology company, so I'm not some knee jerk green tree hugger, just a geek that feels perhaps I'd like my kids to have a world that is hopefully better, not worse, for my generations existance.
Sorry folks for the rant, but a ranking of 4 for the above annoys me more than I can say.
You're right in your statement that currently cellphones are not the problem, I'd argue however your attitude is.
I'd like to see more sensitive CCDs, too, but the film camera people have wanted more sensitive film that wasn't so blasted grainy for decades now, and they haven't gotten it, either.:)
Must have been dreaming when I used Kodak T-MAX (B+W), Kodak EKTAR(C41) and Fuji VELVIA(E6) then:-P
re-fueling weather satellites, which generally have a longer useful lifespan, but a lot of weather satellites are polar orbiters anyway, which don't need as much fuel as geostationary satellites.
Just a couple of points..
Weather satellites are mostly geosynchronous as they feed large area pictures regularly back. (EG METEOSAT Series) The importance in most weather models is the temporal resolution (how quickly you get updates) rather than the spatial resolution. As long as you can see the weather systems you're fine, so this is in the order of kilometres per pixel.
On the other hand Earth Observation satellites (ERS1/2, LANDSAT, SPOT) are in polar orbits because the 'surveying' and environmental monitoring tasks they are used for require a high spatial resolution to see smaller features, with pixels in the order of metres. The trade off is in temporal resolution as it could be many days before the craft repeats the same ground track. (Here SPOT has the advantage as it has steerable instruments)
The unusual platform is the NOAA series of satelittes - the AVHRR instrument on these has a resolution of ~1km, but it is a polar orbiter. Interestingly it broadcasts freely so if you have the kit and the software you get the images. Over here in the UK on a good pass we can see Alaska/New York. Interestingly this provides an image that is good for weather use (as there is a good pass from one of the craft every few hours)but the resolution can be usefully used for Earth Observation use as well (Guess what my thesis used...)
The limit on the lifespan of most observing craft, as opposed to broadcast craft, is the size of the coolant tank. Thermodynamic principles mean that when observing temperatures and in the IR (where there are good windows in the atmosphere absorbtion) the sensor must be colder than the object, otherwise you can't tell what part of the signal is from the object, and which is from the sensor itself. Most craft use liquid hydrogen filled dewars and the coolant runs out usually about 3-4 years after launch.
Fuel in polar orbitors is used to change orbits during the lifespan of the craft (may spend first year doing low level hi-res passes, then boost out in the next few years). At altitudes of 200-300km they also suffer from atmospheric drag and occasionally need to use a small boost to maintain orbit.
When the fuel in this sort of craft becomes below a certain margin, they are usually brought into the atmosphere in a controlled fashion.
Geosynchronous craft ( almost all broadcast craft and weather craft ) fly at an altitude of 38400km (from memory - don't shoot) where for all intents and purposes they maintain the same position over the Earths surface. However its not perfect and they wobble, so fuel is used to correct the orbit and stay within the 2 degree internationally allocated slot. Also if, like Astra, you have several in the same slot you need to stack them at different orbits, and that takes fuel because they are in non-ideal orbits, and you have to keep them all lined up for those fixed dishes!
When the fuel in this sort of craft runs below a certain value they are boosted clear and, being outside the geosynchronous 'event horizon' they drift clear and off into space. No-one wants a rogue fuel-less satellite in this sort of orbit, so internationally the various radio communication agencies are fairly hot on making sure you play by the rules.
In general terms I would expect polar orbiters to use more fuel due to the atmospheric drag. I'm not counting here the fuel used to deliver the craft to its orbit, which is clearly much higher in a geosynchronous craft.
The worst thing that can happen to a broadcast satellite is for its delivery engine/system to fail - then you have a very expensive satellite, probably destined for one of the precious geosynchronous slots, parked in a polar orbit. If you can get a secondary system to it, and control it on its manoevering engines/systems then you get a second chance.
The big problem with space debris is the stuff thats already there, most operational satellites now have thier disposal already planned.
But I do work in telecoms and I'm a qualified yacht navigator (yes that is relevant, bear with me!)
Anyone who knows anything knows that a square wave can be assumed to be a series of sine waves added together.
Why is this important - well a digital signal is what most modern phones will be sending out has lots of nasty harmonics due to its digital nature. (I know most of the US still uses TACS or other such things, I'm talking about GSM/UMTS okay?)
Now if you hold this next to electronics any piece of wire that is an integral number of wavelenghts to a harmonic is going to get an induced current - this is the way antenna work.
Now I have seen this happen in yachts - I have watched a GPS right in front of my eyes reset and lock up as my own phone recieved a text message. I tested it later in port I found that it could disrupt the GPS and cause nastyness on the VHF radio.
I expect that some of the logic circuits had tracks the right length to get a pulse big enough to be seen as a logic state / and there was break through on the anaolgue side of the radio.
Now the stuff in aircraft aint greatly different from this. Draw your own conclusions.
I also used to work for a large UK based aero engine manufacturer (go on, guess we only have one!) - I know how much testing the electronics in engine control systems is tested to.
A modern airframe is a metal box - if you don't understand the term 'Faraday Cage' then go look it up now. In essence it means that any RF energy broadcast in the body essentially stays inside until it finds an area to escape. This vastly increases its chance of interfering with electronics, and also puts your phone to full power to try and overcome the 'interference'.They don't put antenna on the outside of airframes for fun, but because they have to.
Now the aircraft manufacturer has spent a long time carefully testing and integrating the electronics in that airframe to make sure they don't interfer - this is why aircraft electronics are expensive. They have not tested, nor have any control over what electronics you bring on board.
Now in risk management you assess two terms - the possibility of the risk happening and the consequences of that risk. The possibility that phones could interfer with radios/nav instruments/engine systems is real, but unlikely (use of computers probably negligable) Now way that up against the consequences of a systems failure on an aircraft full of people and fuel at just after its taken off. I think the world perhaps understands better the last 12 months just how dangerous that situation can be. In any other mode of transport you can stop and sort out the problem, in the air you get one chance.
If I'm flying transatlantic and you feel making a call, or playing minesweeper is worth risking mine and 300 peoples lives for, forgive me if I don't agree with you.
Note:
In this story the guys involved knew what they were doing and accepted the risk - thats thier choice. Also I don't think the systems on a Grumman Tiger are vital for its flight, just navigation, so its not like they put anyone on the ground at risk. However, not being able to hear the tower is like playing in the middle of the freeway...
I hadn't realised it was a crime to earn money off other people - thought that was the great American Way
Re:Basically what I've got for my emergency radio
on
Do-it-yourself UPS
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· Score: 1
Be warned that the charger rate of any rechargable battery will vary according to the size, given that they use the same chemistry.
Now small batteries need lower currents. This means the charger is cheaper, as it is cheaper to regulate small currents.
If you hook up a battery that is bigger than the original you run the risk of: 1) Not getting your battery fully charged - and this will effect its output voltage and the cutoff voltage of the invert circuits in the UPS so you may end up with LESS run time - wierd or what? 2) You may overheat the charger - if it is a really small battery then it may be a really cheap charge that does very poor current regulation (if at all) so you new big battery sucks current - result very very hot UPS.
And don't, even though it isn't sensible, put a smaller battery in a UPS. It will most likely be charged at well over its normal current rating - this leads to venting of hydrogen in all lead acid batterys, no matter how fancy the technologies - yes even the vented ones (see my reply further up this chain.
Slashdot Mirror
And when the single point of failure in the... ...Cable... ...Controller... ...Drive Motor... ...Hermetic Seal... ...Whole Drive Chassis over temp...
fails, what does you expenditure get you?
How do you think you're going to get two completely seperate drive/head/platter arrays in a 3.5 1 high inch form factor?
What will that do to the heat output?
How does the controller in the drive signal failure of one of the internal 'halves' using the standard protocol?
If the mirror isn't synced how do you examine each half to find the correct half to recover the data from?
Have you ever used RAID, or are we buzzwording here?
If you want that level of reliability buy premium drive mechanisms[1] and look after them.
Otherwise get back to class and stop tinkering with your Dads PC.
[1] If I say SCSI[2] I'll start a flame war, so I'll just say premium because there are other
choices.
[2] Oh shit - I said it *asbestos suit on*
Yep, I'm sure there aren't any good reasons to sitting at home in front of a good home cinema. And no good reasons for feeding a system capable of 800 line resolution and 6/7/8 channels of sound with a source of 200 lines and 2 fuzzy sound channels.
Guess who lost an entire Suse server in the process - ironically our databackup server, the idea being that we had the drives mirrored, and a set of three with one always being in the firesafe, cyclically syncing them every day.
Seemed a cheaper idea at the time than a tape backup - you live and learn.
Just get lots of air moving past the drive.
Don't trust SMART because you're never sure of the calibration - best to get a cheap digital thermometer from Tandy/Radio Shack (whatever you local favourite is!) and compare like with like. Tuck the probe into the cast chassis infront of the controller pcb with a bit of PVC tape so its measuring the temp of the drive chassis, but is out of the airflow.
Just my 2 cents - have fun!
Nahh you were mostly right
SPDIF is Sony Panasonic Digital Interface
TOSLINK is Toshiba Optical System Link
Ones the interface protocol, ones a connector for a certain type of optical transport medium.
Being a daily Reg reader, yes they may have an agenda - it does colour some of the reporting, but also a lot of UK techies read it and my understanding is after the issue was first raised they got considerable correspondance from system integrators that the failure rate was far higher in the UK then was being admitted.
The odd bias/opinion isn't unusual in news and discusion sites *cough*squishdot*cough* now is it??
The biggest mistake I've found is to put the drive in a 5.25 'cooler cage' as these enclose the drive in more metal, and vent it with a 40mm fan, which DOES NOT MOVE MUCH AIR - I remain to be convinced this helps, in my trials the temp of the drive is HIGHER in so called 'cooler bays'.
Why - look at the size of the blades on a 40mm fan, they can practically hardly cool themselves.
I've also cooked 2 Maxtors to death in a Lian-Li removable IDE Rack for similar reasons. I will never again put any 7200 rpm+ drive in a single enclosure with 40mm fans - my data is too important.
If you want to cool drives you need to move a large amount of air - ideal is one of the cages that mounts an 80mm fan with 3 drives - this will move and air and does help. Thats what we used in the RAID server I mention below, and are one of the great advantages of Chieftec cases (also sold under other names)
Failing that put the drives in the bottom so they are in front of the cases lower intake fans, or less ideal in front of the upper rear exhaust fans if you have a larger case (not great as they'll be over the PSU, but with 2 fans it will help)
Bottom line - additional 40mm fans are for decoration only, the cooling is negligable - the only case where they work are where they are built into the drives like some burners - because these draw air through the case that otherwise wouldn't move. As hard drives are hermetically sealed this doesn't count, you need to get air moving at a fair rate over the metal chassis if you want to make an impact - 'cooler bays' don't do this, they don't have the flow rate with thier puny fans, fans grills, and the fact there is very little airspace in the case. Far better just to mount it in a 5.25 mounting rails and lett convection do the rest - there will be more air flow!
The only product that ever made a difference was one that was totally open and had 3 40mm fans across the front(Bay Cooler I think??). But with 3 fans its a noisy little sucker as the 40mm run like crazy to shift enough air, I stil favour a single decent 80mm mounted at the front of a large drive cage, less noisy and more efficient.
Funny - I've always found Enermax supplies to be better than most on its regulation.
Especially when we put together an IDE RAID server with 4x8 drives on 4 3Ware cards, plus boot and CDRom drives.
Not true
So long as you have a cable with a compatible connector on each end it works.
AFAIK optical has two types, the 3.5mm jack like TOSLINK, and the squarer older type; electrical has 3.5mm jack/RCA Phono/COAX
In all cases all that is happening is that there is a bitstream of data from the transport to the DAC - so long as it fits the CD 'bitstream standard' (44.1Khz 16 Bit etc) you're home and dry
Most decent semi-pro/pro-sumer soundcards can have a daughterboard/breakout box with the same optical sockets as used on HI-FI
So you are saying that it doesn't matter what is being said, if an unelected member of the community believes that they have no right to contribute to the discussion then they can flag thier speech such that most members of the community will not be able to read what they say?
Do I need to point out that in a discussion about the evils of censoring peoples access to information how ironic your standpoint is?
And this time I choose not to post anon, to hell with it I've bugger all karma to lose.
If you transmit something via RF, anyone can listen to it.
/. comments as it does security...
You are physically able to receive it, and yes you can listen to it.
That does not mean it is legal.
Use of most of the RF spectrum is regulated to protect it. Internationally certain frequencies are agreed (such as GSM Frequencies, MF Ship frequencies) and the protection of these is enforced by the local Radio Communication Ageny (in UK - equivalent in your country)
Now the use of transmitting and receiving equipment is usually regulated by a licence, unless the band it works on has been derestricted.
Often it means the equipment can be freely sold, but can only be used if you are authorised.
As a holder of certification in VHF/MF Marine Bands, and SSB I have to make a (legal) commitment not to act on information I gain in course of using the equipment, and to protect the privacy of that communication.
If you think about it that is no different from a CEO not selling shares based on inside information, your ISP not using data in your plain text mail, the phone company not using information from phone calls. In all these cases legally authorised people will come across information for reasons that are legal, but are not entilted to act on it as that would be illegal. non authorised people have no right to say shin up the pole and connect a phone handset to your house wires.
Mainly I'm responding to the issues to do with RF, thats a bit off topic.
On topic of course it doesn't matter if how Reuters obtained the information, if its release to the public was not legal.
And crucially I can't see in any of the reports that Reuters gained that information via a URL - seems to me some conclusions have been leapt to. I've not seen any URL published by Reuters.
If the pdf was obtained via telnet using a password, or via SSH (call the ID code a 'key') surely that would fit the words that Intentia are using.
Remember folks - Assumption is the Mother Of All Fsck Ups.
That applies equally the
At least I don't live the side of the pond where they patented the swing as a jok (funny) and one-click-shopping (not funny) Mind you I guess we had a technological society going for longer, not that we are doing toooo welll these days....
Cable Select essentially auto-configures non disk devices
So your hard drive still needs to be flagged master if you want your OS to boot.
But it does mean newbies can plug a CD-ROM device in thats been delivered in CS mode, and its controller will be slave if its bundled next to a drive, master if its got the cable to itself
1. Stock IDE can Hotswap with correct cradle (kinda like SCSI can, so long as its an SCA connector), but does need controller like HighPoint that has the smarts to know whats going on.
2. Ditto Warm Swap
3. Agree
4. 80 conductor cables are limited to 40cm, and BTW are not differential as some say, they just have interleaved grounds to help cut the crosstalk.
5. Err, thats something to do with the drive, not the bus it talks over
6. Round cables are a bad idea, you destroy the whole point of the individual grounds I mentioned in point 4, the agro on the bus will cut your data throughput, and your data could be corrupting. See my other post. People like Compaq can get away with it because they know exactly what will be in the case (like no l33t cold cathode tube producing tons of EMF, and a kewl port in the side to destroy the cases EMF shielding anyway; to pick two problems from thin air)
7. Live in a part of the world that uses 50 fps PAL, trust me its better. Also no one in thier right minds uses uncompressed video when there are perfectly good broadcast standard codecs like the DV ones around. Guess you like the hard life.
8a. Agreed - thats why RAID exists - you can get better performance and/or reliablity than an individual drive unit regardless of the interface type.
8b. You mean like that internal volatile cache in your CPU, or that one in the buffer in your SCSI/IDE/MEMORY bus? The way to solve uncommitted writes is a journalling filesystem or 60USD of UPS, its not a problem of the interface.
I could explain why, but its better done and funnier here Dans Data - Fancy IDE leads - The Terrible Truth
If you don't follow the physics then trust me, I do, he knows, ditch the cables if you run faster than UltraATA33 over them if you value your data.
Use SiSoft Sandra to benchmark the drives, if they go faster at Ultra33 than at Ultra66 then you have problems. Been there, done the test with my Western Digital 80Gb/8Mb cache pair, seen the effects of nasty cable.
One CRC error will just slow the bus down, two errors in the same transmission the ATA standard won't detect and you get a corrupt byte on the disk. Finding that in the zip of l33t t00lz you had stashed away will really make your day.
Read up on all the physics nasties that happen with parrallel conductors
See my other post further up
You can't treat each pair on its own, you have to account for the electrical fields from the other conductors in the same wire, the nasty spikes from god knows what else is in the same case, and the fact that some idiot just rounded the cable and destroyed the few assmuptions you can make about immpeadance matching on the cable so you don't get nasty refelections.
But yes you can have parrallel/serial hybrids, but generally you have one or the other. Otherwise you have to cope with both techniques problems!!
All of IDE's shortcomings are fixed by SCSI
Define 'SCSI' and 'IDE', there are after all many standards. I assume you mean UltraATA33/66/100/133 vs SCSI2UW/SCSI3 to compare like with like!
But both are parrallel systems, and irrespective of the largely irrelvant SCSI vs IDE pissing contest, the problem that needs to be solved is the limitations of parrallel communications.
Parrallel comms has a problem as clock speeds get higher, the immpeadance of the wires gets harder to predict, your error checking and correcting (People do know thats there right?) technology has to get smarter. The timing differences on each conductor start to get near the same order as the clock pulses and you can't figure out if that bit is in the current word or the last. Multi conductor cables are terribly sensitive to crosstalk and other interference. Basically when it comes to high clockspeeds/frequencies then parrallel technology hits limitations.
Serial technology uses less conductors, so the immpeadance of the cable is much more predictable, its also less error prone as there are no real timing issues, and the error correction is easier. You can transmit on inverted pairs and largely reject environmental noise, and with only a couple of data wires crosstalk is predictable and can be coped with. Okay it has to go 8 times as fast to get the same throughput as an 8bit parrallel, 16 times as fast for 16bit parrallel and so on, but we're getting good at fast silicon these days.
So why do we have parrallel, and why is it old tech?
Because when you are limited by the clock speed of the silicon, parrallel moves data faster. Thats why your PC/UNIX box is choc full of parrallel interfaces between devices/chips, because the limitation used to be clock speed.
Now we are reaching clock speeds where physics starts to hurt on multi conductor cables, but now we can build very fast silicon so we can exploit low conductor count cables. As a bonus they are much better at covering distances.
This is why both SCSI and IDE have solved the problem in similar ways. Serial ATA / fibreChannel SCSI (yes I know that can be optical, but its still serial transmission)
In the quest for high clock speeds, then expect to see serial interfaces becoming the norm. What protocal they are talking (SCSI/SATA/USB/IEE1394) is largely irrelevant.
I thank you, and I'll leave the fanboys in both camps to slugg it out amongst themselves...
RAID (Redundant Array of Inexpensive Disks)
The RAID acronym is now Redundant Array of Independant Disks
'Inexpensive' refers back to the time that build a decent sized drive that presented itself to the host as a single entity was easier with an array of small drives, because of the huge cost of larger drives.
'Independant' is more in keeping with the modern reason for build such arrays.
You actually think you can navigate with just your two eyes?
Yes, and I can prove it.
I sail with a friend who's inner ears were damaged by an ear infection in childhood, leaving him with no inate sense of balance. So his entire balance is now done visually.
Does it slow him up? Well he's my dads age, is an ex British Olympic Fin Class sailor, and is now blue water cruising and is an Ocean Yachmaster / Instructor.
I guess if you can cope with the heaving deck of a yacht, you can cope with anything.
The advantage of course is that motion sickness is generally caused by a conflict of 'ear' balance and 'visual' balance (for want of better terms) so he doesn't get seasick. Thats the only way I actually found out, when I mentioned in conversation that he never got sick in rough seas, you'd never ever be able to tell otherwise.
Actually the reason you get motion sickness, and those panaromic cinemas fool you into thinking you are on a roller coaster is because your eyes are very important to navigation and balance.
Of course having the two systems (ear/visual) is a very good idea evolutionary, because one compensates for the weakness in the other.
But knowing that a blind colleuge of mine doesn't fall over in a heap, and my sailing companion doesn't either, I think I can justify in saying humans can operate with only one system perfectly well
Nor are the chemicals in them a significant danger. Computer monitors, yes, contain a lot of lead. But all these other stories about the dangers of electronic waste are bullshit scare stories
You are, sir, entitled to your opinion, but I'm afraid to say the chemicals are a danger.
Look up the details on what cadmium can do to you, wonder why lithium is used for its phsycological effects in treatment of mental disorders, check out some of the chemicals used in and for the manufacturing of PCBs.
A GSM/CDMA phone is likely to be the most complicated (in terms of function versus size/power) electronic device you will ever own. Its worth 200-300UKP, and yet thanks to the marketing and lazyness they are changed each season/provider because they are heavily subsidised (at least in Europe) so the user never appreciates the true cost. Then the user whine about being stiffed for roaming...
And most galling of all is that some people just seem to feel its all right to use up and then chuck away resources. Have we learned nothing from the 'mostly harmless' chemicals in aerosols, the devastating effects of acid rain, the NOx/SOx pollution from massive consumption of fossil fuels?
Just because its cheap doesn't make it right. Slavery was very cheap, and I'm not sure that paying some poor SOB 2 USD a day to go and mine the copper/cadmium/etc for you to chuck in the skip is much better.
FYI my background is in physics and environmental sciences, and now I work for a wireless technology company, so I'm not some knee jerk green tree hugger, just a geek that feels perhaps I'd like my kids to have a world that is hopefully better, not worse, for my generations existance.
Sorry folks for the rant, but a ranking of 4 for the above annoys me more than I can say.
You're right in your statement that currently cellphones are not the problem, I'd argue however your attitude is.
Speaking as a prosumer in both the SLR and Digital arenas...
m
A very good discusion can be found at : http://www.users.qwest.net/~rnclark/scandetail.ht
Thanks to Dan's Data - D60 Review for pointing me there!
I'd like to see more sensitive CCDs, too, but the film camera people have wanted more sensitive film that wasn't so blasted grainy for decades now, and they haven't gotten it, either. :)
:-P
Must have been dreaming when I used Kodak T-MAX (B+W), Kodak EKTAR(C41) and Fuji VELVIA(E6) then
That would be Linus
re-fueling weather satellites, which generally have a longer useful lifespan, but a lot of weather satellites are polar orbiters anyway, which don't need as much fuel as geostationary satellites.
Just a couple of points..
Weather satellites are mostly geosynchronous as they feed large area pictures regularly back. (EG METEOSAT Series) The importance in most weather models is the temporal resolution (how quickly you get updates) rather than the spatial resolution. As long as you can see the weather systems you're fine, so this is in the order of kilometres per pixel.
On the other hand Earth Observation satellites (ERS1/2, LANDSAT, SPOT) are in polar orbits because the 'surveying' and environmental monitoring tasks they are used for require a high spatial resolution to see smaller features, with pixels in the order of metres. The trade off is in temporal resolution as it could be many days before the craft repeats the same ground track. (Here SPOT has the advantage as it has steerable instruments)
The unusual platform is the NOAA series of satelittes - the AVHRR instrument on these has a resolution of ~1km, but it is a polar orbiter. Interestingly it broadcasts freely so if you have the kit and the software you get the images. Over here in the UK on a good pass we can see Alaska/New York. Interestingly this provides an image that is good for weather use (as there is a good pass from one of the craft every few hours)but the resolution can be usefully used for Earth Observation use as well (Guess what my thesis used...)
The limit on the lifespan of most observing craft, as opposed to broadcast craft, is the size of the coolant tank. Thermodynamic principles mean that when observing temperatures and in the IR (where there are good windows in the atmosphere absorbtion) the sensor must be colder than the object, otherwise you can't tell what part of the signal is from the object, and which is from the sensor itself. Most craft use liquid hydrogen filled dewars and the coolant runs out usually about 3-4 years after launch.
Fuel in polar orbitors is used to change orbits during the lifespan of the craft (may spend first year doing low level hi-res passes, then boost out in the next few years). At altitudes of 200-300km they also suffer from atmospheric drag and occasionally need to use a small boost to maintain orbit.
When the fuel in this sort of craft becomes below a certain margin, they are usually brought into the atmosphere in a controlled fashion.
Geosynchronous craft ( almost all broadcast craft and weather craft ) fly at an altitude of 38400km (from memory - don't shoot) where for all intents and purposes they maintain the same position over the Earths surface. However its not perfect and they wobble, so fuel is used to correct the orbit and stay within the 2 degree internationally allocated slot. Also if, like Astra, you have several in the same slot you need to stack them at different orbits, and that takes fuel because they are in non-ideal orbits, and you have to keep them all lined up for those fixed dishes!
When the fuel in this sort of craft runs below a certain value they are boosted clear and, being outside the geosynchronous 'event horizon' they drift clear and off into space. No-one wants a rogue fuel-less satellite in this sort of orbit, so internationally the various radio communication agencies are fairly hot on making sure you play by the rules.
In general terms I would expect polar orbiters to use more fuel due to the atmospheric drag. I'm not counting here the fuel used to deliver the craft to its orbit, which is clearly much higher in a geosynchronous craft.
The worst thing that can happen to a broadcast satellite is for its delivery engine/system to fail - then you have a very expensive satellite, probably destined for one of the precious geosynchronous slots, parked in a polar orbit. If you can get a secondary system to it, and control it on its manoevering engines/systems then you get a second chance.
The big problem with space debris is the stuff thats already there, most operational satellites now have thier disposal already planned.
I am not (yet) I pilot
But I do work in telecoms and I'm a qualified yacht navigator (yes that is relevant, bear with me!)
Anyone who knows anything knows that a square wave can be assumed to be a series of sine waves added together.
Why is this important - well a digital signal is what most modern phones will be sending out has lots of nasty harmonics due to its digital nature. (I know most of the US still uses TACS or other such things, I'm talking about GSM/UMTS okay?)
Now if you hold this next to electronics any piece of wire that is an integral number of wavelenghts to a harmonic is going to get an induced current - this is the way antenna work.
Now I have seen this happen in yachts - I have watched a GPS right in front of my eyes reset and lock up as my own phone recieved a text message. I tested it later in port I found that it could disrupt the GPS and cause nastyness on the VHF radio.
I expect that some of the logic circuits had tracks the right length to get a pulse big enough to be seen as a logic state / and there was break through on the anaolgue side of the radio.
Now the stuff in aircraft aint greatly different from this. Draw your own conclusions.
I also used to work for a large UK based aero engine manufacturer (go on, guess we only have one!) - I know how much testing the electronics in engine control systems is tested to.
A modern airframe is a metal box - if you don't understand the term 'Faraday Cage' then go look it up now. In essence it means that any RF energy broadcast in the body essentially stays inside until it finds an area to escape. This vastly increases its chance of interfering with electronics, and also puts your phone to full power to try and overcome the 'interference'.They don't put antenna on the outside of airframes for fun, but because they have to.
Now the aircraft manufacturer has spent a long time carefully testing and integrating the electronics in that airframe to make sure they don't interfer - this is why aircraft electronics are expensive. They have not tested, nor have any control over what electronics you bring on board.
Now in risk management you assess two terms - the possibility of the risk happening and the consequences of that risk. The possibility that phones could interfer with radios/nav instruments/engine systems is real, but unlikely (use of computers probably negligable) Now way that up against the consequences of a systems failure on an aircraft full of people and fuel at just after its taken off. I think the world perhaps understands better the last 12 months just how dangerous that situation can be. In any other mode of transport you can stop and sort out the problem, in the air you get one chance.
If I'm flying transatlantic and you feel making a call, or playing minesweeper is worth risking mine and 300 peoples lives for, forgive me if I don't agree with you.
Note:
In this story the guys involved knew what they were doing and accepted the risk - thats thier choice. Also I don't think the systems on a Grumman Tiger are vital for its flight, just navigation, so its not like they put anyone on the ground at risk. However, not being able to hear the tower is like playing in the middle of the freeway...
I hadn't realised it was a crime to earn money off other people - thought that was the great American Way
Be warned that the charger rate of any rechargable battery will vary according to the size, given that they use the same chemistry.
Now small batteries need lower currents. This means the charger is cheaper, as it is cheaper to regulate small currents.
If you hook up a battery that is bigger than the original you run the risk of:
1) Not getting your battery fully charged - and this will effect its output voltage and the cutoff voltage of the invert circuits in the UPS so you may end up with LESS run time - wierd or what?
2) You may overheat the charger - if it is a really small battery then it may be a really cheap charge that does very poor current regulation (if at all) so you new big battery sucks current - result very very hot UPS.
And don't, even though it isn't sensible, put a smaller battery in a UPS. It will most likely be charged at well over its normal current rating - this leads to venting of hydrogen in all lead acid batterys, no matter how fancy the technologies - yes even the vented ones (see my reply further up this chain.