Re: (OT) Storage (8*IDE HDs) any experiences?
On Wed, May 02, 2001 at 03:24:53PM -0500, Dimitri Maziuk wrote: Oh, and (since they sound like the kind of servers that come with monitors) don't plug monitors into UPSen. Uhm, sorry, why not? I have connected a monitor (14, normally turned off) to our server and to his USV so I can even read my email if the whole campus is without mail. What's the problem with that apart from the shorter period you can run on battery power? Thanks Torsten pgpTYNwp9ihQU.pgp Description: PGP signature
Re: (OT) Storage (8*IDE HDs) any experiences?
Hi, On Tue, May 01, 2001 at 07:46:42PM +1000, Hamish Moffatt wrote: On Tue, May 01, 2001 at 11:03:06AM +0200, Russell Coker wrote: On Monday 30 April 2001 00:04, Hamish Moffatt wrote: I don't see why. Nor is this any different to any external drives. You have a hefty ground connection between the power supplies anyway (the mains, plus the metal case acting as ground). Alas, one generally cannot assume this! Here in The Netherlands, most residential wall outlets do not have a ground connection. This causes mysterious computer illnesses. The server won't come up on reboot, when the printer is attached. The problem is gone after the printer gets a proper earth ground. After purchase of a new Brand Quality monitor, the harddisk appears damaged. The bootup ID string is corrupt after 12 or so characters. Fixing the monitor's wall outlet fixes the harddisk. Multiply the fun as you start plugging in network cables. But I digress.. Frame ground isn't so important here I think, circuit ground is what you should care about. In principle, these are different things. In most applications they also are strictly different things, but pc's just isn't one of them. External drives generally don't use an ATA interface! I am not confidant of the main earth acting as a suitable earth for the DC power. True, but I don't see this as a big issue. All traditional external drive systems that I know of have: - Their own power supply in the external disk housing. - A connection to the host that carries only signals, not power. This connection has a dedicated frame ground line (in fact, any decent cabling has its shielding connected to frame ground.) I think it would be better to deliberately turn them on in order, rather than trying to guess at the same time. Turn the hard drives on first. They may or may not spin up while the controller is powered off. Then turn on the main supply. AFAIK harddisks have two motors: - A start motor that speed up the disk's rotation very quickly, but eats a lot of current; It is normally only used at boot time. - A continuous motor that spins with a very precisely controlled speed and consumes considerably less power. It works all the time when the disk is operating normally. If some day you turn on your computer and suddenly the disk is dead, you should be able to hear from the disk's cries of agony which of the two motors burned out ;-) (There is an (urban?) legend that harddisk manufacturers classify batches by the motor that is expected to fail first. If the start motor is weak, it will be a scsi disk, if the continuous motor is weak, it will be an ide disk.) All scsi disks (that I know of) have this feature, called Spin Delay. If you configure the disk appropriately, it will not attempt to spin up on powerup until it is explicitly asked to do so when initialised by the scsi host controller. This way the system can distribute the surges in current draw caused by the powerful start motors in the disks. There was a presentation at a Linux Users of Victoria meeting some years ago about doing hot-swap IDE hard drives with cheap standard hardware. My recollection is that the power lines of the hard drive had to be connected in a particular order... I have sucessfully powered down, disconnected, reconnected and powered back up again an IDE disk once (this is why you should take anything I claim here with a grain of salt.) No umount or even swapoff, just disable dma and cross my fingers ;-) The disk was only off for 30 secs or so. What probably helped is that the disk is an old, low-rpm disk. Modern disks seem to have a tendency to draw a lot power at once when power is plugged in from a running system, throwing the whole system into a hardware reset. A rather unfortunate side-effect when hotplugging. It can be really nice to have cheap (free) old hardware (junk) to mess around with. How else would I have discovered that sometimes, you _can_ successfully hotplug isa cards ;-) Standard power supplies may have sequencing to switch the supplies on a known order. That doesn't stop you powering them from different power supplies though, as the sequencing isn't under motherboard control. On Monday 30 April 2001 16:11, PiotR wrote: A good solution for this might be to connect the first PS's output to the other, so the voltage is the same, and there's no massive current flow across the data cables. That's if both PSU's have exactly the same voltage. If one provides a slightly higher voltage than the other then it will try to power everything itself (at least until the current drain lowers the output voltage). Also if two PSUs with different voltages are connected together with insufficient load then reverse current will flow through the PSU with the lower voltage! Well, I'm not an electrical engineer, but I don't think it really works like that. *** WARNING *** My
Re: (OT) Storage (8*IDE HDs) any experiences?
On Wed, May 02, 2001 at 11:21:49PM +0200, PiotR wrote: On Wed, May 02, 2001 at 08:30:10AM +1000, Hamish Moffatt wrote: In power combining applications like these, balancing diodes or resistors are usually used. It's not good just to connect the outputs together. What's the difference between those and a standard diode? Nothing. I was just referring to their application. Just like you have decoupling or bypass capacitors; they're just capacitors, with a particular application named. Hamish -- Hamish Moffatt VK3SB [EMAIL PROTECTED] [EMAIL PROTECTED]
Re: (OT) Storage (8*IDE HDs) any experiences? - diodes
On Wed, May 02, 2001 at 04:49:27PM -0700, Alvin Oga wrote: the diodes need to be power diodes... vs signal diodes given you cannot tie the power supplies at two diff voltages together... you have to isolate it somehow... ( the power diode method ) I'm a bit hazy on how this actually works, but I would guess that each supply's output goes through a diode (forward biased) and the lower potential sides of the diodes would be connected. Thus not much current flows back the other way. but more importantly, its primary purpose is to allow for the two power supply at different voltages ( +5.25v and +4.75v ) to be tied together at these extremes... the diodes wont helpand the dioes will simply burn up due to the current it has to pass to get to that voltage one side being a diode drop ( 0.7v ) across itself.. - a power mosfet is better suited ... You will need some large diodes and you may well need cooling ie heatsinks. Hamish -- Hamish Moffatt VK3SB [EMAIL PROTECTED] [EMAIL PROTECTED]
Re: (OT) Storage (8*IDE HDs) any experiences? - diodes
Hi! at these extremes... the diodes wont helpand the dioes will simply burn up due to the current it has to pass to get to that voltage one side being a diode drop ( 0.7v ) across itself.. - a power mosfet is better suited ... hmm, mosfet doesn't make sense to me - IIRC they only work like switches I think you should use Shotkey-diods the largest one i know could pass 200 ampere - and they've less than ~0.4V voltage drop :wq - until next mail B-), l8r Peter -- :~~ [EMAIL PROTECTED] ~~: : student of technical computer science : : university of applied sciences krefeld (germany) : ~~ FD314F21 C7 AE 2F 28 C1 33 71 77 0D 77 CD 6E 58 E9 06 6B
Re: (OT) Storage (8*IDE HDs) any experiences? - diodes
At Thu, 3 May 2001 22:36:27 +0200 , Peter Bartosch [EMAIL PROTECTED] wrote: hmm, mosfet doesn't make sense to me - IIRC they only work like switches A MOSFET is a type of field-effect transistor ... hence the FET part of the name -- it can be sued for much more than a switch. Get your own FREE E-mail address at http://www.linuxfreemail.com Linux FREE Mail is 100% FREE, 100% Linux, and 100% yours!
Re: (OT) Storage (8*IDE HDs) any experiences? - diodes
Hi! at these extremes... the diodes wont helpand the dioes will simply burn up due to the current it has to pass to get to that voltage one side being a diode drop ( 0.7v ) across itself.. - a power mosfet is better suited ... hmm, mosfet doesn't make sense to me - IIRC they only work like switches I think you should use Shotkey-diods the largest one i know could pass 200 ampere - and they've less than ~0.4V voltage drop Hi! Mosfets are a kind of transistors with less loss of energy than a bipoar type. I agree that the only thing you could use is a shottky diode, the drop is about 0.1-0.2 Volts, I think; therefore it won't produce so much heat and maybe you won't even need any heatsinks for them. But I think it is generally not a good thing to reduce the supply voltage by 0.2 Volts this way, because computers are very sensitive to voltage changes... If there will be a high load for only a short time, the voltage maybe drops down the specs and your components are down. Regards, Stephan Hachinger
Re: (OT) Storage (8*IDE HDs) any experiences? - diodes
http://www.dell.com/us/en/bsd/products/model_pedge_1_pedge_2550.htm ...Has a system with dual power supplies. If anyone is interested in putting together a system like that, I suggest they go ahead and buy one. Otherwise, let's leave the design stuff to the power supply engineers at Power One and the other big power supply companies. They've got loads of (trained) people to take care of the design debates (including the use of Schottky Diodes). If further discussion on this toppic is desired, perhaps news:alt.engineering.electrical would be a more appropriate forum (or any of a number of other resources that show up in a google search). The debate was off-topic to begin with, strayed even further, yet stayed interesting with the concerns over load-ballancing supplies. Debating design features of power supplies is really wandering off of the beaten path... especially given the lack of experience most of us (the members of debian-user) have with the subject. Sorry for adding to the noise, but geez, this list is chatty enough already to be almost unmanagable. Bottom line: let's let the discussion die or else move it over to another list or NG. --Rich (loads of chatter deleted) -- _ Rich Puhek ETN Systems Inc. _
Re: (OT) Storage (8*IDE HDs) any experiences?
On Wed, May 02, 2001 at 03:24:53PM -0500, Dimitri Maziuk wrote: On Wed, May 02, 2001 at 08:18:20PM +0100, Matthew Sackman wrote: ... Every production server that I've seen that has 2 PSUs has both continuously running. At hopefully 50% capacity. Interesting. Could you post the list of brand names/vendors so that we'll know what not to buy. Well their design may have changed over the last year or so, but afaik, Penguin Computing do this, and the other one that I know of I can't remember the name of - a UK based company that custom builds servers. Can't remember the name, sorry. If you're looking to purcahse a server for use as a co-location server in a hosting company then be advised that they do not like dual power inlet servers (will charge more), and they are also very concerned over the size of your server. I.e. don't buy a dell poweredge cos they're too big and you'll get charged more for them. Also be aware that any decent power supply will have a quickblow internal fuse, thus the fuse in the plug is redundant. In this case (and ONLY in this case), it is safe to foil-wrap the fuse in the PLUG to ensure it never blows. This way you can have redundant power supplies through one inlet. Be ABSOLUTELY CERTAIN THAT THE PSUs ARE INTERNALLY FUSED. If I were you, I would use a company that will custom build you a box, basically using components you specify: i.e. down to the model number of the mobo. That way, and only that way, can you be certain what you're getting. Personally, I'd build the server from scratch myself, but if you're not happy doing that then get a company to build it for you. I would not go for an off-the-shelf server. ... Of course, the irony is that as they are both routed to the same power inlet, if the fuse in the plug goes then you're buggered anyway! :-) Tip of the day: plug them into 2 different UPSen connected to separate power lines (pref. separate circuits). Oh, and (since they sound like the kind of servers that come with monitors) don't plug monitors into UPSen. Um, nope. ?6000 (uk pound) dual PIII 1Gb DRAM, U160 SCSI. Used by a very professional web hosting company. Hope this helps, Matthew -- Matthew Sackman Nottingham, ENGLAND Using Debian/GNU Linux Enjoying computing pgpFsOdL3N01Z.pgp Description: PGP signature
Re: (OT) Storage (8*IDE HDs) any experiences? - diodes
hi ya... though we are getting slightly off topic... - dual power supply issues... the problem is how to connect two power supplies together... one at 5.25v and the other at extreme of 4.75v if using just a diode...( no matter what kind - power or schottky )... it wont work as one diode will have a bigger voltage drop across it than its normal .1v or .7v or whatever it might be... voltage drop is NOT the issue you need something that will allow a range of Vce or Vsd that will pass the normal current and also support the surge current when you first turn on the powersupply to spin the drives... and since diodes/resistors are not active devices... you will incurr significant loss of regulation and huge current spikes ( good way to get a disk go *poof* on ya ) dual power supply is tricky biz...guess thats why its $500 for a pair... or more or less... not the atx/pc stuff for $25 each have fun alvin On Thu, 3 May 2001, Stephan Hachinger wrote: Hi! at these extremes... the diodes wont helpand the dioes will simply burn up due to the current it has to pass to get to that voltage one side being a diode drop ( 0.7v ) across itself.. - a power mosfet is better suited ... hmm, mosfet doesn't make sense to me - IIRC they only work like switches I think you should use Shotkey-diods the largest one i know could pass 200 ampere - and they've less than ~0.4V voltage drop Hi! Mosfets are a kind of transistors with less loss of energy than a bipoar type. I agree that the only thing you could use is a shottky diode, the drop is about 0.1-0.2 Volts, I think; therefore it won't produce so much heat and maybe you won't even need any heatsinks for them. But I think it is generally not a good thing to reduce the supply voltage by 0.2 Volts this way, because computers are very sensitive to voltage changes... If there will be a high load for only a short time, the voltage maybe drops down the specs and your components are down. Regards, Stephan Hachinger -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of unsubscribe. Trouble? Contact [EMAIL PROTECTED]
Re: (OT) Storage (8*IDE HDs) any experiences? +55v
Alvin.. have you really been following this thread at all? On Tue, May 01, 2001 at 05:43:57PM -0700, Alvin Oga wrote: and if the power supply to the disk dies... than you're out of luck or if the powersupply tot eh motherboard dies... you'd be out of luck too So what? It's always been about load sharing, not redundancy. in which case...whats thepoint of having 2 PS ??? - if it cannot handle the load...get a bigger power supply - having 2 power supplies complicates things.. and some devices running at 12.5v and others at 11.5v.. at the extreme voltage ranges ... similarly for +5v range and +3.3 ranges...( all kinds of possible random timing problems?? I don't think this is likely to cause much problem really. For one thing, the logic between the controller and the drive is running on 5V (I'd guess), not 12V. 5V logic is generally pretty tolerant... if you do have 2 power supplies.. you should invest in a properly designed load-sharing power circuitry such that the other supply can drive all devices it needs by itself... Huh? The disks and the motherboard will never be independent. Summary: I think disks and motherboard on separate power supplies will work. Connect the grounds together. (They'll be connected by mains neutral/earth, as well as case ground, anyway, but just to be thorough.) Yes, there will be differences in the supply voltages, but I don't see that being a significant problem with 5V logic. No, I haven't tried it. But yes, I do know something about electronics. Hamish -- Hamish Moffatt VK3SB [EMAIL PROTECTED] [EMAIL PROTECTED]
Re: (OT) Storage (8*IDE HDs) any experiences?
On Fri, Apr 27, 2001 at 12:05:11PM -0500, Dimitri Maziuk wrote: On Thu, Apr 26, 2001 at 05:32:31PM -0700, Alvin Oga wrote: ... - even if you had 2 power supplies... - most motherboards only has one atx power connector True. And if you went for redundant PS's and a mobo that supports them, the cost would go way up. - are the two power supplies properly doing load sharing... Usually not. I imagine that's too hard and not worth the trouble anyway: what you usually want is redundancy, not load sharing. (I mean, if one PS dies, it will overload and kill the other one pretty fast. Not a good idea. And if each PS can handle the load alone, there's little point in sharing the load.) Every production server that I've seen that has 2 PSUs has both continuously running. At hopefully 50% capacity. There is no switch-over - if one goes then the other has to cope with both. Of course, the irony is that as they are both routed to the same power inlet, if the fuse in the plug goes then you're buggered anyway! :-) Matthew -- Matthew Sackman Nottingham, ENGLAND Using Debian/GNU Linux Enjoying computing pgpLx4UEbTxIg.pgp Description: PGP signature
Re: (OT) Storage (8*IDE HDs) any experiences?
Dell Poweredge 2450 style servers is what you're looking for. They have two power supplies, each with its own power cord. Yes, it can run on one PS... the last one I set up ran that way on my desk since I only had one cord handy. Of course, you'll want to make damn sure the grounds are at the same potential, so doing funny tricks with where you plug them in could be a bad idea. Another nice thing about this (and probably all the machines Matthew's referring to) is that the motherboard doesn't need to support multiple supplies, nor do the hard drives, fans, tape drives, etc. I agree with Matthew in that there _is_ a reason to share the load, actually a few that I can think of. Let's say you have a pair of 300W supplies on a box that draws 250W at rest. Rather than let one supply crank along at 250W, let's let both supplies run at about 125W. That way, both supplies will run cooler (Depending on the supply design, the supply may actually have slightly lower efficiency at the lower load factor, but that's a trade off we can live with). Also consider what happens if the load was near the capacity of a single supply, and spiked over the capacity. If we were using the second supply as a backup to only be switched in if the primary failed, how would that be handled? --Rich Matthew Sackman wrote: On Fri, Apr 27, 2001 at 12:05:11PM -0500, Dimitri Maziuk wrote: On Thu, Apr 26, 2001 at 05:32:31PM -0700, Alvin Oga wrote: ... - even if you had 2 power supplies... - most motherboards only has one atx power connector True. And if you went for redundant PS's and a mobo that supports them, the cost would go way up. - are the two power supplies properly doing load sharing... Usually not. I imagine that's too hard and not worth the trouble anyway: what you usually want is redundancy, not load sharing. (I mean, if one PS dies, it will overload and kill the other one pretty fast. Not a good idea. And if each PS can handle the load alone, there's little point in sharing the load.) Every production server that I've seen that has 2 PSUs has both continuously running. At hopefully 50% capacity. There is no switch-over - if one goes then the other has to cope with both. Of course, the irony is that as they are both routed to the same power inlet, if the fuse in the plug goes then you're buggered anyway! :-) Matthew -- Matthew Sackman Nottingham, ENGLAND -- _ Rich Puhek ETN Systems Inc. _
Re: (OT) Storage (8*IDE HDs) any experiences?
On Wed, May 02, 2001 at 08:18:20PM +0100, Matthew Sackman wrote: ... Every production server that I've seen that has 2 PSUs has both continuously running. At hopefully 50% capacity. Interesting. Could you post the list of brand names/vendors so that we'll know what not to buy. ... Of course, the irony is that as they are both routed to the same power inlet, if the fuse in the plug goes then you're buggered anyway! :-) Tip of the day: plug them into 2 different UPSen connected to separate power lines (pref. separate circuits). Oh, and (since they sound like the kind of servers that come with monitors) don't plug monitors into UPSen. Dima (sorry, couldn't resist) -- E-mail dmaziuk at bmrb dot wisc dot edu (@work) or at crosswinds dot net (@home) http://www.bmrb.wisc.edu/descript/gpgkey.dmaziuk.ascii -- GnuPG 1.0.4 public key I'm going to exit now since you don't want me to replace the printcap. If you change your mind later, run -- magicfilter config script
Re: (OT) Storage (8*IDE HDs) any experiences?
On Wed, May 02, 2001 at 03:13:34PM -0500, Rich Puhek wrote: ... I agree with Matthew in that there _is_ a reason to share the load, actually a few that I can think of. Let's say you have a pair of 300W supplies on a box that draws 250W at rest. Rather than let one supply crank along at 250W, let's let both supplies run at about 125W. That way, both supplies will run cooler (Depending on the supply design, the supply may actually have slightly lower efficiency at the lower load factor, but that's a trade off we can live with). IANAEE/Physicist and it's been (dear Goddess, has it been this long?) over 15 years since school, so my recollection is a bit fuzzy... Lower efficiency at lower load will probably mean more energy is dissipated as heat. So 2 PSUs * 125W ea will generate more heat than 1 PSU * 250W. Depending on box design this may cause CPU/disks to operate at higher temperatures, reducing their lifespan. In fact, there will be some point at which each individual PSU will run just as hot as if it handled all the load on its own (you can be sure your box will draw exactly that much load, thank you Mr Murphy). I'm not arguing that this is the case, I'm saying that this kind of argument can be twisted and turned any which way you like. I had mid-80s AT PSUs. They'd still be working if I didn't have to move house and throw all that junk out. If a PSU lasts for 15 years, will 2 load-sharing PSUs last 30 years? Do I care? (Will I last 30 more years?) I know that CPU will maybe last 1/5th of that, disks maybe 1/3rd. So what is it I'm going to achieve by setting up load-balancing PSUs? ... Also consider what happens if the load was near the capacity of a single supply, and spiked over the capacity. If we were using the second supply as a backup to only be switched in if the primary failed, how would that be handled? Well if you mean some piece of hardware suddently decides to draw $BIGNUM times its normal current, the PSU will die. Depending on the design, there's a circuit somewhere (eg. on the backplane) that does the appropriate magic and switches the second PSU on. Of course it'll die very soon too, unless the FPOH in question magically fixed itself in the meantime. Sometimes the magic fails -- I remember the look on my boss's face when he pulled a hot-swappable PSU out of a live swerver, and the box went down. Oops. (Only happened once; we later tried to reproduce the problem, quite unsuccessfully: PSUs switched over like a charm, every bloody time. Surprise, surprise.) Dima -- E-mail dmaziuk at bmrb dot wisc dot edu (@work) or at crosswinds dot net (@home) http://www.bmrb.wisc.edu/descript/gpgkey.dmaziuk.ascii -- GnuPG 1.0.4 public key I'm going to exit now since you don't want me to replace the printcap. If you change your mind later, run -- magicfilter config script
Re: (OT) Storage (8*IDE HDs) any experiences?
On Wed, May 02, 2001 at 08:30:10AM +1000, Hamish Moffatt wrote: On Tue, May 01, 2001 at 08:42:04PM +0200, PiotR wrote: If you short circuit both PS's outputs then the voltage is the same and there won't be any reverse current, neither in the data cables. So te load will be distributed between both PS. In power combining applications like these, balancing diodes or resistors are usually used. It's not good just to connect the outputs together. What's the difference between those and a standard diode? I think if you use a diode to connect the outputs you are limiting the current flow in one way only. And why would you want to do this? Also I didn't understood why Alvin said If one PS dies you are dead I believe it will only fail to power those drives attached to them. Hamish -- Hamish Moffatt VK3SB [EMAIL PROTECTED] [EMAIL PROTECTED] -- Pedro Larroy Tovar. PiotR | http://omega.resa.es/piotr/ [EMAIL PROTECTED]
Re: (OT) Storage (8*IDE HDs) any experiences?
-- _ Rich Puhek ETN Systems Inc. 2125 1st Ave East Hibbing MN 55746 tel: 218.262.1130 email: [EMAIL PROTECTED] _
Re: (OT) Storage (8*IDE HDs) any experiences?
On Wed, May 02, 2001 at 11:21:49PM +0200, PiotR wrote: On Wed, May 02, 2001 at 08:30:10AM +1000, Hamish Moffatt wrote: On Tue, May 01, 2001 at 08:42:04PM +0200, PiotR wrote: If you short circuit both PS's outputs then the voltage is the same and there won't be any reverse current, neither in the data cables. So te load will be distributed between both PS. In power combining applications like these, balancing diodes or resistors are usually used. It's not good just to connect the outputs together. What's the difference between those and a standard diode? I think if you use a diode to connect the outputs you are limiting the current flow in one way only. And why would you want to do this? Could this topic die or go somewhere else? Please? Thanks :) -- Nathan Norman - Staff Engineer | A good plan today is better Micromuse Ltd. | than a perfect plan tomorrow. mailto:[EMAIL PROTECTED] | -- Patton pgpv6C7PVihHC.pgp Description: PGP signature
Re: (OT) Storage (8*IDE HDs) any experiences?
(Sorry about the blank email... too much caffeene got me a twitchy trigger finger). Dimitri Maziuk wrote: In fact, there will be some point at which each individual PSU will run just as hot as if it handled all the load on its own (you can be sure your box will draw exactly that much load, thank you Mr Murphy). Hmmm, I'm doubtful that that's the case if our load is around 25% to 50% or something like that. That's based on almost a pure guess, but I recall UPS efficiency numbers of something like high 90% numbers for almost full load versus 85% or so at 50% load. Obviously, a very lightly loaded power supply will put out about as much heat regardless of whether it's running at 1% or 2% capacity, but I'm thinking that will diverge fairly quickly. Also, in most PS and case designs, the PS should have a negligable effect on the heat transfer of the box, given that its fan exhausts directly to the exterior of the case. If the case is ventilated through the power supply (as common in desktop PCs and low end servers), there will be a small change, depending on the temperature within the power supply case (been about 4-years since I decided 'Thermo and an ME degree weren't for me, so the ideas are fuzzy for me too). I'm not arguing that this is the case, I'm saying that this kind of argument can be twisted and turned any which way you like. Very true, which is why redundancy will be the main factor, not heat production. I had mid-80s AT PSUs. They'd still be working if I didn't have to move house and throw all that junk out. If a PSU lasts for 15 years, will 2 load-sharing PSUs last 30 years? Do I care? (Will I last 30 more years?) I know that CPU will maybe last 1/5th of that, disks maybe 1/3rd. So what is it I'm going to achieve by setting up load-balancing PSUs? Well, those mid-80s AT PSUs (in general, I mean) seem to have either been A) oversized for the AT PCs or B) just better quality than normal desktop-grade power supplies of today. (BTW: I recall hearing that Intel speced Pentium CPUs for a lifetime of 10 or 20 years in normal usage... used as a rationale for overclocking and the reduced lifespan it causes). No, I don't anticipate a linear relationship between load and lifespan, nor would I anticipate a linear relationship between load and heat disappated, heat dissapated and lifespan, etc... I would however, anticipate that keeping a power supply running somewhere under its full rated capacity will increase its lifespan to some extent. Also, in a load-balancing configuration, you eliminate the ... Also consider what happens if the load was near the capacity of a single supply, and spiked over the capacity. If we were using the second supply as a backup to only be switched in if the primary failed, how would that be handled? Well if you mean some piece of hardware suddently decides to draw $BIGNUM times its normal current, the PSU will die. Depending on the design, there's a circuit somewhere (eg. on the backplane) that does the appropriate magic and switches the second PSU on. Of course it'll die very soon too, unless the FPOH in question magically fixed itself in the meantime. I was thinking more like the combined load in the box was something like 95% of the rated capacity of the power supply, then spiked to 110% (like having a bunch of SCSI drives spin up). A decent power supply probably won't let the smoke out, but it probably won't give the best power either. A redundant load-sharing arrangement would have both supplies running at something like 42.5%, then spike to something like 55%. Granted, this is a bit of a stretch, but I've seen too many cases recently of servers in a simple consumer PC box that gradually got stuffed full of SCSI drives until a PS failed. Sometimes the magic fails -- I remember the look on my boss's face when he pulled a hot-swappable PSU out of a live swerver, and the box went down. Oops. (Only happened once; we later tried to reproduce the problem, quite unsuccessfully: PSUs switched over like a charm, every bloody time. Surprise, surprise.) Dima Like you said, Mr. Murphy pays a visit every now and then :-) (whew... ok, I'm done.. this topic has wandered far enough!) --Rich -- _ Rich Puhek ETN Systems Inc. _
Re: (OT) Storage (8*IDE HDs) any experiences?
On Wed, May 02, 2001 at 11:21:49PM +0200, PiotR wrote: Also I didn't understood why Alvin said If one PS dies you are dead I believe it will only fail to power those drives attached to them. This would only work in a raid =1 setup. You'd have one one drive on PS1, and its mirror on PS2 md0= hda hdc md1= hde hdg hda hde on PS 1 hdc hdg on PS 2 I really wouldn't want to create a setup like this myself. You should really have a power supply that can handle all of your devices, and a backup PS that isn't used until needed. Mike
Re: (OT) Storage (8*IDE HDs) any experiences?
On Wed, May 02, 2001 at 04:52:03PM -0500, Nathan E Norman wrote: On Wed, May 02, 2001 at 11:21:49PM +0200, PiotR wrote: I think if you use a diode to connect the outputs you are limiting the current flow in one way only. And why would you want to do this? Could this topic die or go somewhere else? Please? Thanks :) Probably not, sorry. ;) Mike
Re: (OT) Storage (8*IDE HDs) any experiences? - diodes
hi ya I think if you use a diode to connect the outputs you are limiting the current flow in one way only. And why would you want to do this? the diodes need to be power diodes... vs signal diodes given you cannot tie the power supplies at two diff voltages together... you have to isolate it somehow... ( the power diode method ) - even putting two batteries in parallel dont work... - - and it gets real fun when you put car batteries in parallel - and if you can get it working... it makes for a very good UPS - - one car battery lasts about 15hrs ...for a P3-500 class server - sitting idle with no AC power yes...it might limit the current... and a resistor is bad too cause they both nullifies/weaken the accurate voltage regulation.. - ie. big current spikes will occur but more importantly, its primary purpose is to allow for the two power supply at different voltages ( +5.25v and +4.75v ) to be tied together at these extremes... the diodes wont helpand the dioes will simply burn up due to the current it has to pass to get to that voltage one side being a diode drop ( 0.7v ) across itself.. - a power mosfet is better suited ... think we're going off course...but... thats the fun of watching things blow up in the lab when ne does whacky things like connect two power supplies together??? ( smoke test or heat test ) c ya alvin http://www.Linux-1U.net ...
Re: (OT) Storage (8*IDE HDs) any experiences?
On Sun, Apr 29, 2001 at 10:14:35AM +0200, Russell Coker wrote: On Sunday 29 April 2001 06:48, Brandon High wrote: On Sat, Apr 28, 2001 at 11:50:26PM +0200, Andreas Bombe wrote: The IBM SCSI disk I have here has a jumper to delay spin up depending on SCSI ID so that an array of those would spin up sequentially if they all had those jumper set (and different IDs, which they need anyway). Maybe there are IDE drives built with RAIDs in mind offering some similar option? I doubt it, but with a sufficiently large case (or small power supply) it may be possible to stick a 2nd (or 3rd) power supply in. Drives could be plugged into the second PS while the MB is powered off of the primary PS. That sounds like a really bad idea to me. In a regular setup the IDE controller and the drive get power from the same source. So if the signals on the cable have more current going one way than the other then the difference will be made up on the 0V line on the PSU. If you have separate PSU's then the difference will go through other lines of the data cable. This is something that is likely to be fatal to drives and motherboards. But if you try it please let me know how it works. ;) I've used a second power supply just to test out some hard drives, because I didn't want them to hang off the PS. It worked great. Mike
Re: (OT) Storage (8*IDE HDs) any experiences?
On Monday 30 April 2001 00:04, Hamish Moffatt wrote: On Sun, Apr 29, 2001 at 10:14:35AM +0200, Russell Coker wrote: In a regular setup the IDE controller and the drive get power from the same source. So if the signals on the cable have more current going one way than the other then the difference will be made up on the 0V line on the PSU. If you have separate PSU's then the difference will go through other lines of the data cable. I don't see why. Nor is this any different to any external drives. You have a hefty ground connection between the power supplies anyway (the mains, plus the metal case acting as ground). External drives generally don't use an ATA interface! I am not confidant of the main earth acting as a suitable earth for the DC power. On Monday 30 April 2001 01:01, Brian May wrote: Another thing to watch out for is timing differences. Eg. if you turn on one power supply before the other. Or if one power supply generates good power before the other. I would assume (hope!) the original poster plans to run both power supplies from the same central switch, in order to minimise problems here. Designers of the interface need to take into consideration if it is going to be used for external devices powered by external power or internal devices. A number of factors need to be taken into account ranging from internal delays in the power supply, logic levels, cable length vs cable quality vs speed of communication vs reliability of communication, ground loops, etc. There was a presentation at a Linux Users of Victoria meeting some years ago about doing hot-swap IDE hard drives with cheap standard hardware. My recollection is that the power lines of the hard drive had to be connected in a particular order... On Monday 30 April 2001 16:11, PiotR wrote: A good solution for this might be to connect the first PS's output to the other, so the voltage is the same, and there's no massive current flow across the data cables. That's if both PSU's have exactly the same voltage. If one provides a slightly higher voltage than the other then it will try to power everything itself (at least until the current drain lowers the output voltage). Also if two PSUs with different voltages are connected together with insufficient load then reverse current will flow through the PSU with the lower voltage! Go to http://www.raidzone.com/ if you want affordable IDE-based RAID solutions without all this bother. -- http://www.coker.com.au/bonnie++/ Bonnie++ hard drive benchmark http://www.coker.com.au/postal/ Postal SMTP/POP benchmark http://www.coker.com.au/projects.html Projects I am working on http://www.coker.com.au/~russell/ My home page
Re: (OT) Storage (8*IDE HDs) any experiences?
On Tue, May 01, 2001 at 11:03:06AM +0200, Russell Coker wrote: On Monday 30 April 2001 00:04, Hamish Moffatt wrote: I don't see why. Nor is this any different to any external drives. You have a hefty ground connection between the power supplies anyway (the mains, plus the metal case acting as ground). External drives generally don't use an ATA interface! I am not confidant of the main earth acting as a suitable earth for the DC power. True, but I don't see this as a big issue. On Monday 30 April 2001 01:01, Brian May wrote: Another thing to watch out for is timing differences. Eg. if you turn on one power supply before the other. Or if one power supply generates good power before the other. I would assume (hope!) the original poster plans to run both power supplies from the same central switch, in order to minimise problems here. I think it would be better to deliberately turn them on in order, rather than trying to guess at the same time. Turn the hard drives on first. They may or may not spin up while the controller is powered off. Then turn on the main supply. There was a presentation at a Linux Users of Victoria meeting some years ago about doing hot-swap IDE hard drives with cheap standard hardware. My recollection is that the power lines of the hard drive had to be connected in a particular order... Standard power supplies may have sequencing to switch the supplies on a known order. That doesn't stop you powering them from different power supplies though, as the sequencing isn't under motherboard control. On Monday 30 April 2001 16:11, PiotR wrote: A good solution for this might be to connect the first PS's output to the other, so the voltage is the same, and there's no massive current flow across the data cables. That's if both PSU's have exactly the same voltage. If one provides a slightly higher voltage than the other then it will try to power everything itself (at least until the current drain lowers the output voltage). Also if two PSUs with different voltages are connected together with insufficient load then reverse current will flow through the PSU with the lower voltage! Yes, that's a bad idea. Hamish -- Hamish Moffatt VK3SB [EMAIL PROTECTED] [EMAIL PROTECTED]
Re: (OT) Storage (8*IDE HDs) any experiences?
Sorry I missed the start of the thread. I would suggest you to buy a simple IDE-to-SCSI Raid Appliance. You don't have the trouble with sizing the Power supply. You get a neat chasis with plug-able disks and you also get the speed of SCSI and the ability to plug it into every server you desire. The prices are quite reasonable. I asume you need it at work, cause more than 4x36GB isnt realy needed for private persons, even if they have a large mp3 archive :) I also missed the start of this thread, but I will share my experience... We built a rackmount backup server with SEVEN 80GB drives, CDROM, floppy, 20GB drive (for root system), etc. We software raided the 7 drives together to make 1 partition. When we first put the system together (using a 300W PS) the drives were making funny noises and we were having stability problems. Somehow (I can't remember exact details) we got the idea that it was a PS problem. So I ordered a high quality 350W PS and our problems went away. We actually like our backup solution. It only cost us about $2800 for over 1/2 terabyte of storage and its maintenance free, fast, and easy to use. On the Windows client side we have loadlin scheduled to boot into linux at night (which uses an NSF system mount), it then rsyncs the client's hard drive, and then reboots the computer back into Windows. Charles Lewis [EMAIL PROTECTED]
Re: (OT) Storage (8*IDE HDs) any experiences?
On Tue, May 01, 2001 at 11:03:06AM +0200, Russell Coker wrote: On Monday 30 April 2001 16:11, PiotR wrote: A good solution for this might be to connect the first PS's output to the other, so the voltage is the same, and there's no massive current flow across the data cables. That's if both PSU's have exactly the same voltage. If one provides a slightly higher voltage than the other then it will try to power everything itself (at least until the current drain lowers the output voltage). Also if two PSUs with different voltages are connected together with insufficient load then reverse current will flow through the PSU with the lower voltage! If you short circuit both PS's outputs then the voltage is the same and there won't be any reverse current, neither in the data cables. So te load will be distributed between both PS. -- Pedro Larroy Tovar. PiotR | http://omega.resa.es/piotr/ [EMAIL PROTECTED]
Re: (OT) Storage (8*IDE HDs) any experiences?
On Tue, May 01, 2001 at 07:46:42PM +1000, Hamish Moffatt wrote: On Tue, May 01, 2001 at 11:03:06AM +0200, Russell Coker wrote: On Monday 30 April 2001 00:04, Hamish Moffatt wrote: I don't see why. Nor is this any different to any external drives. You have a hefty ground connection between the power supplies anyway (the mains, plus the metal case acting as ground). External drives generally don't use an ATA interface! I am not confidant of the main earth acting as a suitable earth for the DC power. True, but I don't see this as a big issue. You could connect the DC grounds of the two supplies together safely. Don't connect any other rails together though. Hamish -- Hamish Moffatt VK3SB [EMAIL PROTECTED] [EMAIL PROTECTED]
Re: (OT) Storage (8*IDE HDs) any experiences?
On Tue, May 01, 2001 at 08:42:04PM +0200, PiotR wrote: If you short circuit both PS's outputs then the voltage is the same and there won't be any reverse current, neither in the data cables. So te load will be distributed between both PS. In power combining applications like these, balancing diodes or resistors are usually used. It's not good just to connect the outputs together. Hamish -- Hamish Moffatt VK3SB [EMAIL PROTECTED] [EMAIL PROTECTED]
Re: (OT) Storage (8*IDE HDs) any experiences? +55v
hi yes gnd should be connected... if +5v, +3.3v is NOT connected together... and assuming you have 2 powersupplies.. and if the power supply to the disk dies... than you're out of luck or if the powersupply tot eh motherboard dies... you'd be out of luck too in which case...whats thepoint of having 2 PS ??? - if it cannot handle the load...get a bigger power supply - having 2 power supplies complicates things.. and some devices running at 12.5v and others at 11.5v.. at the extreme voltage ranges ... similarly for +5v range and +3.3 ranges...( all kinds of possible random timing problems?? if you do have 2 power supplies.. you should invest in a properly designed load-sharing power circuitry such that the other supply can drive all devices it needs by itself... - or just get a powersupply with 2x the capacity too does almost the same trick.. - except if the one supply dies...you're dead... some ( supermicro ) motherboards has dual atx connectors ...but the disks are not yet dual-power supplied... :-( and we wont even talk about the UPS triggering a shutdown in these cases... what a mess... but fun !!! c ya alvin http://www.Linux-Sec.net ... On Wed, 2 May 2001, Hamish Moffatt wrote: On Tue, May 01, 2001 at 07:46:42PM +1000, Hamish Moffatt wrote: On Tue, May 01, 2001 at 11:03:06AM +0200, Russell Coker wrote: On Monday 30 April 2001 00:04, Hamish Moffatt wrote: I don't see why. Nor is this any different to any external drives. You have a hefty ground connection between the power supplies anyway (the mains, plus the metal case acting as ground). External drives generally don't use an ATA interface! I am not confidant of the main earth acting as a suitable earth for the DC power. True, but I don't see this as a big issue. You could connect the DC grounds of the two supplies together safely. Don't connect any other rails together though. Hamish -- Hamish Moffatt VK3SB [EMAIL PROTECTED] [EMAIL PROTECTED] -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of unsubscribe. Trouble? Contact [EMAIL PROTECTED]
Re: (OT) Storage (8*IDE HDs) any experiences?
On Sun, Apr 29, 2001 at 10:14:35AM +0200, Russell Coker wrote: On Sunday 29 April 2001 06:48, Brandon High wrote: On Sat, Apr 28, 2001 at 11:50:26PM +0200, Andreas Bombe wrote: The IBM SCSI disk I have here has a jumper to delay spin up depending on SCSI ID so that an array of those would spin up sequentially if they all had those jumper set (and different IDs, which they need anyway). Maybe there are IDE drives built with RAIDs in mind offering some similar option? I doubt it, but with a sufficiently large case (or small power supply) it may be possible to stick a 2nd (or 3rd) power supply in. Drives could be plugged into the second PS while the MB is powered off of the primary PS. That sounds like a really bad idea to me. In a regular setup the IDE controller and the drive get power from the same source. So if the signals on the cable have more current going one way than the other then the difference will be made up on the 0V line on the PSU. If you have separate PSU's then the difference will go through other lines of the data cable. This is something that is likely to be fatal to drives and motherboards. But if you try it please let me know how it works. ;) A good solution for this might be to connect the first PS's output to the other, so the voltage is the same, and there's no massive current flow across the data cables. Anyone desagrees to this? -- Pedro Larroy Tovar. PiotR | http://omega.resa.es/piotr/ [EMAIL PROTECTED]
Re: (OT) Storage (8*IDE HDs) any experiences?
On Sat, Apr 28, 2001 at 11:50:26PM +0200, Andreas Bombe wrote: The IBM SCSI disk I have here has a jumper to delay spin up depending on SCSI ID so that an array of those would spin up sequentially if they all had those jumper set (and different IDs, which they need anyway). Maybe there are IDE drives built with RAIDs in mind offering some similar option? I doubt it, but with a sufficiently large case (or small power supply) it may be possible to stick a 2nd (or 3rd) power supply in. Drives could be plugged into the second PS while the MB is powered off of the primary PS. -B -- Brandon High [EMAIL PROTECTED] Just think: in a few million years, Barney will be motor oil.
Re: (OT) Storage (8*IDE HDs) any experiences?
hi ya... might be easier/cheaper to use a simple RC delay to deliver power to the IDE disks before the motherboard actually gets the power up - remember that the atx powersupply has a power-ok signal to tell the motherboard go ahead and power up... ( aka the power switch ) each ide disks takes about 1Amp at 12v to sping up the drive... and most atx powersupply is on that borderline at 8 drives.. 4-drives is no big issue you can fit 2 power supply into a 1U chassis if you used 8x8 sized atx motherboards... one of the 1u cases...put a power supply in the front and another at the back. ( kinda funky ) c ya alvin On Sat, 28 Apr 2001, Brandon High wrote: On Sat, Apr 28, 2001 at 11:50:26PM +0200, Andreas Bombe wrote: The IBM SCSI disk I have here has a jumper to delay spin up depending on SCSI ID so that an array of those would spin up sequentially if they all had those jumper set (and different IDs, which they need anyway). Maybe there are IDE drives built with RAIDs in mind offering some similar option? I doubt it, but with a sufficiently large case (or small power supply) it may be possible to stick a 2nd (or 3rd) power supply in. Drives could be plugged into the second PS while the MB is powered off of the primary PS.
Re: (OT) Storage (8*IDE HDs) any experiences?
On Sunday 29 April 2001 06:48, Brandon High wrote: On Sat, Apr 28, 2001 at 11:50:26PM +0200, Andreas Bombe wrote: The IBM SCSI disk I have here has a jumper to delay spin up depending on SCSI ID so that an array of those would spin up sequentially if they all had those jumper set (and different IDs, which they need anyway). Maybe there are IDE drives built with RAIDs in mind offering some similar option? I doubt it, but with a sufficiently large case (or small power supply) it may be possible to stick a 2nd (or 3rd) power supply in. Drives could be plugged into the second PS while the MB is powered off of the primary PS. That sounds like a really bad idea to me. In a regular setup the IDE controller and the drive get power from the same source. So if the signals on the cable have more current going one way than the other then the difference will be made up on the 0V line on the PSU. If you have separate PSU's then the difference will go through other lines of the data cable. This is something that is likely to be fatal to drives and motherboards. But if you try it please let me know how it works. ;) -- http://www.coker.com.au/bonnie++/ Bonnie++ hard drive benchmark http://www.coker.com.au/postal/ Postal SMTP/POP benchmark http://www.coker.com.au/projects.html Projects I am working on http://www.coker.com.au/~russell/ My home page
Re: (OT) Storage (8*IDE HDs) any experiences?
On Sat, Apr 28, 2001 at 11:50:26PM +0200, Andreas Bombe wrote: The IBM SCSI disk I have here has a jumper to delay spin up depending on SCSI ID so that an array of those would spin up sequentially if they all had those jumper set (and different IDs, which they need anyway). Sorry I missed the start of the thread. I would suggest you to buy a simple IDE-to-SCSI Raid Appliance. You don't have the trouble with sizing the Power supply. You get a neat chasis with plug-able disks and you also get the speed of SCSI and the ability to plug it into every server you desire. The prices are quite reasonable. I asume you need it at work, cause more than 4x36GB isnt realy needed for private persons, even if they have a large mp3 archive :) BTW: I would suggest to use only Master-Disks on those IDE Channels, since those are much faster. One IDE-to-SCSI Solutoin I saw had 8 IDE Channels for 8 Disks, so no slave needs to be used. Greetings Bernd -- (OO) -- [EMAIL PROTECTED] -- ( .. ) [EMAIL PROTECTED],linux.de,debian.org} http://home.pages.de/~eckes/ o--o *plush* 2048/93600EFD [EMAIL PROTECTED] +497257930613 BE5-RIPE (OO) When cryptography is outlawed, bayl bhgynjf jvyy unir cevinpl!
Re: (OT) Storage (8*IDE HDs) any experiences?
On Sun, Apr 29, 2001 at 10:14:35AM +0200, Russell Coker wrote: In a regular setup the IDE controller and the drive get power from the same source. So if the signals on the cable have more current going one way than the other then the difference will be made up on the 0V line on the PSU. If you have separate PSU's then the difference will go through other lines of the data cable. I don't see why. Nor is this any different to any external drives. You have a hefty ground connection between the power supplies anyway (the mains, plus the metal case acting as ground). Hamish -- Hamish Moffatt VK3SB [EMAIL PROTECTED] [EMAIL PROTECTED]
Re: (OT) Storage (8*IDE HDs) any experiences?
On Friday 27 April 2001 19:05, Dimitri Maziuk wrote: I imagine the dangerous part would be when you turn the thing on and it tries to spin up all those disks. You could put them to sleep shortly after bootup and get the load down, but if PS doesn't blow on startup it probably won't blow under normal load either. I just checked one of my 46G ATA drives. 500ma @ 12V and 300ma @ 5V, that's 7.5W of power. A typical PSU will be 250W, even if the hard drives take double power at spin-up time there will still be plenty to spare... -- http://www.coker.com.au/bonnie++/ Bonnie++ hard drive benchmark http://www.coker.com.au/postal/ Postal SMTP/POP benchmark http://www.coker.com.au/projects.html Projects I am working on http://www.coker.com.au/~russell/ My home page
Re: (OT) Storage (8*IDE HDs) any experiences?
On Fri, Apr 27, 2001 at 12:05:11PM -0500, Dimitri Maziuk wrote: I imagine the dangerous part would be when you turn the thing on and it tries to spin up all those disks. You could put them to sleep shortly after bootup and get the load down, but if PS doesn't blow on startup it probably won't blow under normal load either. The IBM SCSI disk I have here has a jumper to delay spin up depending on SCSI ID so that an array of those would spin up sequentially if they all had those jumper set (and different IDs, which they need anyway). Maybe there are IDE drives built with RAIDs in mind offering some similar option? -- Andreas E. Bombe [EMAIL PROTECTED]DSA key 0x04880A44 http://home.pages.de/~andreas.bombe/http://linux1394.sourceforge.net/
Re: (OT) Storage (8*IDE HDs) any experiences?
On Fri, Apr 27, 2001 at 12:49:13AM -0500, Rahul Jain wrote: On Thu, Apr 26, 2001 at 09:33:19PM -0700, Brandon High wrote: On Thu, Apr 26, 2001 at 09:42:16PM -0400, [EMAIL PROTECTED] wrote: IDE causes a bit of a performance hit, I don't think we're talking high speed file access here though... cheap is the objective. You'd be suprised at the performance hit. I had 2 drives/channel and suffered from really bad performance with the on-board Ultra66 controller. I installed a PCI controller (Promise Ultra 66) and put every drive on its own channel. Things are much happier now and about 3x faster. The best part is that the card only costs about $25. Yep, but the problem there is figuring out how to get each channel on a unique IRQ. With some BIOSes, it's just not possible. Yeah but we don't need no stinkin' performance for this particular application. We expect to receive large volumes of data (1TB/yr) that will be backed up on tape upon arrival. Occasionally somebody will want to retrieve some of it. So, they could just send us an e-mail and a tape monkey could restore the file in question. It's just that a) we'd like to have another copy of the data anyway, just in case, and b) all things considered, IDE drives are cheaper than tapes. Of course, a wall of 8-drive peecees will have heaps of its own problems. Dima -- E-mail dmaziuk at bmrb dot wisc dot edu (@work) or at crosswinds dot net (@home) http://www.bmrb.wisc.edu/descript/gpgkey.dmaziuk.ascii -- GnuPG 1.0.4 public key We're sysadmins. Sanity happens to other people. -- Chris King in asr
Re: (OT) Storage (8*IDE HDs) any experiences?
On Thu, Apr 26, 2001 at 05:32:31PM -0700, Alvin Oga wrote: ... - even if you had 2 power supplies... - most motherboards only has one atx power connector True. And if you went for redundant PS's and a mobo that supports them, the cost would go way up. - are the two power supplies properly doing load sharing... Usually not. I imagine that's too hard and not worth the trouble anyway: what you usually want is redundancy, not load sharing. (I mean, if one PS dies, it will overload and kill the other one pretty fast. Not a good idea. And if each PS can handle the load alone, there's little point in sharing the load.) I imagine the dangerous part would be when you turn the thing on and it tries to spin up all those disks. You could put them to sleep shortly after bootup and get the load down, but if PS doesn't blow on startup it probably won't blow under normal load either. Dima -- E-mail dmaziuk at bmrb dot wisc dot edu (@work) or at crosswinds dot net (@home) http://www.bmrb.wisc.edu/descript/gpgkey.dmaziuk.ascii -- GnuPG 1.0.4 public key We're sysadmins. Sanity happens to other people. -- Chris King in asr
