Re: Dangerously dedicated yet again (was: cvs commit: src/sys/kern subr_diskmbr.c)
: IBM DTLA drives are known to rotate fast enough near the spindle : that the sustained write speed exceeds the ability of the controller : electronics to keep up, and results in crap being written to disk. I would adssume it actually the tracks FURTHEREST from the spindle.. With ZBR, anything is possible. Wouldn't the linear speed be faster closer to the spindle at 7200 RPM than at the edge? The stunning ignorance being displayed in this thread appears to have reached an all-time low. *sigh* -- ... every activity meets with opposition, everyone who acts has his rivals and unfortunately opponents also. But not because people want to be opponents, rather because the tasks and relationships force people to take different points of view. [Dr. Fritz Todt] V I C T O R Y N O T V E N G E A N C E To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-current in the body of the message
Re: Dangerously dedicated yet again (was: cvs commit: src/sys/kern subr_diskmbr.c)
: Wouldn't the linear speed be faster closer to the spindle at 7200 RPM : than at the edge? : :The stunning ignorance being displayed in this thread appears to have :reached an all-time low. : :*sigh* Ah, another poor soul who didn't read the first sentence of tuning(7). -Matt To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-current in the body of the message
Re: Dangerously dedicated yet again (was: cvs commit: src/sys/kern subr_diskmbr.c)
David W. Chapman Jr. wrote: : IBM DTLA drives are known to rotate fast enough near the spindle : that the sustained write speed exceeds the ability of the controller : electronics to keep up, and results in crap being written to disk. I would adssume it actually the tracks FURTHEREST from the spindle.. Wouldn't the linear speed be faster closer to the spindle at 7200 RPM than at the edge? Linear speed is closes at the edge, but magnetic domain density is higher at the spindle, for a uniform rotation rate. I think that the electronics ended up being designed for the average rate. PS: The encoding frequency is higher at the spindle, as well. -- Terry To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-current in the body of the message
Dangerously dedicated yet again (was: cvs commit: src/sys/kern subr_diskmbr.c)
On Sunday, 9 December 2001 at 22:52:58 +1030, Daniel O'Connor wrote: On 09-Dec-2001 [EMAIL PROTECTED] wrote: (The other day a coworker of mine wanted to use DD for some IBM DTLA disks, because he'd heard that the disks performed better that way - something to do with scatter-gather not working right unless you used DD. I'm highly skeptical about this since I have my own measurements from IBM DTLA disks partitioned the normal way, ie. NOT DD, and they show the disks performing extremely well. Anybody else want to comment on this?) Sounds like an Old Wives Tale to me. I don't understand the need some people have for using something that is labelled as DANGEROUS. I don't understand the need some people have for labelling something as DANGEROUS when it works nearly all the time. We don't have many disks which are shared between different platforms, but that will change. As you know, I have the ability to hot swap disks between an RS/6000 platform and an ia32 platform. The RS/6000 disks will never have a Microsoft partition table on them. They will have BSD partition tables on them. Why call this dangerous? Greg -- See complete headers for address and phone numbers To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-current in the body of the message
Re: Dangerously dedicated yet again (was: cvs commit: src/sys/kern subr_diskmbr.c)
Greg Lehey wrote: [ ... IBM DTLA drives ... ] IBM DTLA drives are known to rotate fast enough near the spindle that the sustained write speed exceeds the ability of the controller electronics to keep up, and results in crap being written to disk. This is not often a problem with windows, the FS of shich fills sectors in towards the spindle, so you only hit the problem when you near the disk full state. Do a Google/Tom's Hardware search to reassure yourself that I am not smoking anything. I don't understand the need some people have for using something that is labelled as DANGEROUS. I don't understand the need some people have for labelling something as DANGEROUS when it works nearly all the time. It's because you have to reinstall, should you want to add a second OS at a later date (e.g. Linux, or Windows). We don't have many disks which are shared between different platforms, but that will change. As you know, I have the ability to hot swap disks between an RS/6000 platform and an ia32 platform. The RS/6000 disks will never have a Microsoft partition table on them. They will have BSD partition tables on them. Why call this dangerous? Your use is orthogonal to the most common expected usage, which is disks shared between OSs on a single platform, rather than disks shared between a single OS on multiple platforms. -- Terry To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-current in the body of the message
Re: Dangerously dedicated yet again (was: cvs commit: src/sys/kern subr_diskmbr.c)
On Sunday, 9 December 2001 at 18:46:24 -0800, Terry Lambert wrote: Greg Lehey wrote: [ ... IBM DTLA drives ... ] No, that wasn't me. IBM DTLA drives are known to rotate fast enough near the spindle that the sustained write speed exceeds the ability of the controller electronics to keep up, and results in crap being written to disk. What about the cache? This is not often a problem with windows, the FS of shich fills sectors in towards the spindle, so you only hit the problem when you near the disk full state. This sounds very unlikely. Do a Google/Tom's Hardware search to reassure yourself that I am not smoking anything. I think I'd rather put the shoe on the other foot. This looks like high-grade crack. Who was smoking it? I don't understand the need some people have for using something that is labelled as DANGEROUS. I don't understand the need some people have for labelling something as DANGEROUS when it works nearly all the time. I *did* write this. It's because you have to reinstall, should you want to add a second OS at a later date (e.g. Linux, or Windows). So all dedicated installations are dangerous? I would have to do that whether I had a Microsoft partition table or not if I had already used the entire disk for FreeBSD. We don't have many disks which are shared between different platforms, but that will change. As you know, I have the ability to hot swap disks between an RS/6000 platform and an ia32 platform. The RS/6000 disks will never have a Microsoft partition table on them. They will have BSD partition tables on them. Why call this dangerous? Your use is orthogonal to the most common expected usage, which is disks shared between OSs on a single platform, rather than disks shared between a single OS on multiple platforms. Expected usage is to install once and then never change it. Greg -- See complete headers for address and phone numbers To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-current in the body of the message
Re: Dangerously dedicated yet again (was: cvs commit: src/sys/kern subr_diskmbr.c)
Greg Lehey wrote: [ ... IBM DTLA drives ... ] No, that wasn't me. I didn't quote the full thing; that's what the brackets and ellipsis was for. IBM DTLA drives are known to rotate fast enough near the spindle that the sustained write speed exceeds the ability of the controller electronics to keep up, and results in crap being written to disk. What about the cache? Good point. The cache is known to not actually flush to disk when ordered to do so. See the EXT3FS article on www.ibm.com/developerworks for more details. This is not often a problem with windows, the FS of shich fills sectors in towards the spindle, so you only hit the problem when you near the disk full state. This sounds very unlikely. I know, doesn't it? Good thing Tom's Hardware is so thorough, or we might never have known this, with everyone on the verge of discovering it simply dismissing it as very unlikely. 8^). Do a Google/Tom's Hardware search to reassure yourself that I am not smoking anything. I think I'd rather put the shoe on the other foot. This looks like high-grade crack. Who was smoking it? Tom's Hardware, IBM, CNET, Storave Review, etc.. http://www6.tomshardware.com/storage/00q3/000821/ibmdtla-07.html http://www.storage.ibm.com/hdd/prod/deskstar.htm http://computers.cnet.com/hardware/0-1092-418-1664463.html?pn=3lb=2ob=0tag=st\.co.1092.bottom.1664463-3 http://www.storagereview.com/welcome.pl?/http://www.storagereview.com/jive/sr/thread.jsp?forum=2thread=12485 I suggest the search: http://google.yahoo.com/bin/query?p=DTLA+drive+problemhc=0hs=0 It's because you have to reinstall, should you want to add a second OS at a later date (e.g. Linux, or Windows). So all dedicated installations are dangerous? I would have to do that whether I had a Microsoft partition table or not if I had already used the entire disk for FreeBSD. Yes. I don't understand your point. Your use is orthogonal to the most common expected usage, which is disks shared between OSs on a single platform, rather than disks shared between a single OS on multiple platforms. Expected usage is to install once and then never change it. No, expected usage is to purchase a machine with an OS preinstalled, and then install FreeBSD/Linux/BeOS/other third party OS as an also ran, rather than the primary OS. -- Terry To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-current in the body of the message
Re: Dangerously dedicated yet again (was: cvs commit: src/sys/kern subr_diskmbr.c)
Greg Lehey wrote: [ ... DTLA drives ... ] Do a Google/Tom's Hardware search to reassure yourself that I am not smoking anything. I think I'd rather put the shoe on the other foot. This looks like high-grade crack. Who was smoking it? For your further amusement, here is a pointer to the class action lawsuit against IBM on the 75GXP DTLA drives: http://www.tech-report.com/news_reply.x/3035/3/ It includes a pointer to the PDF of the complaint form. -- Terry To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-current in the body of the message
Re: Dangerously dedicated yet again (was: cvs commit: src/sys/kern subr_diskmbr.c)
On google search for: deskstar 75gxp class action http://www.theregister.co.uk/content/54/22412.html http://www.pcworld.com/news/article/0,aid,67608,00.asp etc... So apparently my warning about these drives in 'man tuning' is still appropriate :-) -Matt : IBM DTLA drives are known to rotate fast enough near the spindle : that the sustained write speed exceeds the ability of the controller : electronics to keep up, and results in crap being written to disk. : : What about the cache? : :Good point. The cache is known to not actually flush to disk when :ordered to do so. See the EXT3FS article on www.ibm.com/developerworks :for more details. : : This is not often a problem with windows, the FS of shich fills : sectors in towards the spindle, so you only hit the problem when you : near the disk full state. : : This sounds very unlikely. : :I know, doesn't it? Good thing Tom's Hardware is so thorough, or we :might never have known this, with everyone on the verge of discovering :it simply dismissing it as very unlikely. 8^). :... To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-current in the body of the message
IBM DTLA drives (was: Re: Dangerously dedicated yet again (was: cvs commit: src/sys/kern subr_diskmbr.c) )
Matthew Dillon wrote: : etc... So apparently my warning about these drives in 'man tuning' is : still appropriate :-) : :-Matt : : : IBM DTLA drives are known to rotate fast enough near the spindle : : that the sustained write speed exceeds the ability of the controller : : electronics to keep up, and results in crap being written to disk. : : :I would adssume it actually the tracks FURTHEREST from the spindle.. This is the first I've heard of the alleged controller electronics performance problem. My understanding is that the failures are due to manufacturing problems, but people have apparently experienced software lockups as well. What is not in doubt is that there have been some severe problems with this model. Yes there are two problems. The physical failure problem seems to be mostly restricted to the 75GXP. However the electronics/bandwidth/ density/whatever-it-is problem is uniform across the entire DTLA line. We stopped using 75GXP's at work a while back, but we still regularly suffer from the electronics/bandwidth/whatever-it-is problem on 30G DTLA drives on a daily basis. Cheers, -Peter -- Peter Wemm - [EMAIL PROTECTED]; [EMAIL PROTECTED]; [EMAIL PROTECTED] All of this is for nothing if we don't go to the stars - JMS/B5 To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-current in the body of the message
Re: Dangerously dedicated yet again (was: cvs commit: src/sys/kern subr_diskmbr.c)
On Sun, Dec 09, 2001 at 06:46:24PM -0800, Terry Lambert wrote: It's because you have to reinstall, should you want to add a second OS at a later date (e.g. Linux, or Windows). I think it has more to do with the drive going on a new motherboard that might not boot with dangerously dedicated than the above. -- David W. Chapman Jr. [EMAIL PROTECTED] Raintree Network Services, Inc. www.inethouston.net [EMAIL PROTECTED] FreeBSD Committer www.FreeBSD.org To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-current in the body of the message
Re: Dangerously dedicated yet again (was: cvs commit: src/sys/kern subr_diskmbr.c)
David W. Chapman Jr. wrote: On Sun, Dec 09, 2001 at 06:46:24PM -0800, Terry Lambert wrote: It's because you have to reinstall, should you want to add a second OS at a later date (e.g. Linux, or Windows). I think it has more to do with the drive going on a new motherboard that might not boot with dangerously dedicated than the above. The concept of dangerously dedicated significantly predates BIOS being unable to boot such drives, either because of antivirus checks, or because of automatic fictitious geometry determination by Adaptec or NCR (now Symbios) controllers, which end up getting divide by zero errors when parsing the fictitious partition table that the FreeBSD dangerously dedicate mode includes in its boot block. In fact, I remember installing 386BSD dangerously dedicated on an ATT WGS 386 ESDI drive, back in 1992. -- Terry To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-current in the body of the message
Re: Dangerously dedicated yet again (was: cvs commit: src/sys/kern subr_diskmbr.c)
: IBM DTLA drives are known to rotate fast enough near the spindle : that the sustained write speed exceeds the ability of the controller : electronics to keep up, and results in crap being written to disk. I would adssume it actually the tracks FURTHEREST from the spindle.. Wouldn't the linear speed be faster closer to the spindle at 7200 RPM than at the edge? -- David W. Chapman Jr. [EMAIL PROTECTED] Raintree Network Services, Inc. www.inethouston.net [EMAIL PROTECTED] FreeBSD Committer www.FreeBSD.org To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-current in the body of the message
Re: Dangerously dedicated yet again (was: cvs commit: src/sys/kern subr_diskmbr.c)
David W. Chapman Jr. wrote: : IBM DTLA drives are known to rotate fast enough near the spindle : that the sustained write speed exceeds the ability of the controller : electronics to keep up, and results in crap being written to disk. I would adssume it actually the tracks FURTHEREST from the spindle.. Wouldn't the linear speed be faster closer to the spindle at 7200 RPM than at the edge? This particular tangent of the disk partitioning thread has gone *way* off topic. :-) Cheers, -Peter -- Peter Wemm - [EMAIL PROTECTED]; [EMAIL PROTECTED]; [EMAIL PROTECTED] All of this is for nothing if we don't go to the stars - JMS/B5 To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-current in the body of the message
Re: Dangerously dedicated yet again (was: cvs commit: src/sys/kern subr_diskmbr.c)
David W. Chapman Jr. wrote: On Sun, Dec 09, 2001 at 06:46:24PM -0800, Terry Lambert wrote: It's because you have to reinstall, should you want to add a second OS at a later date (e.g. Linux, or Windows). I think it has more to do with the drive going on a new motherboard that might not boot with dangerously dedicated than the above. .. And the mere presence of one of the disks that causes the bios to lock up at boot. Note that this is a particularly bad thing in laptops. There are three classes of behavior: 1) You luck out and it works 2) You get a bios divide-by-zero fault when you *boot* of the disk. This shows up as a 'BTX fault'. If you check the lists, a good number of btx faults posted to the lists have int=0 (divide by zero) in them. The problem is more widespread than it appears. 3) You get a system lockup when booting the *computer* if *any* DD disk is attached anywhere at all. This is what killed the Thinkpad T20*, A20*, 600X etc. After all the yelling we did at IBM, it turned out to be FreeBSD's fault. It also happens on Dell systems. It kills all IA64 boxes if a FreeBSD/i386 disk is attached anywhere. An additional problem is that because boot1 has got a fdisk table embedded in it unconditionally, a freebsd partition *looks* like it has got a recursive MBR in it. This is what is really bad and is what is killing us on newer systems. What really sucks is that there is **NO WAY** to remove it with the tools that we have except a hex editor. Cheers, -Peter -- Peter Wemm - [EMAIL PROTECTED]; [EMAIL PROTECTED]; [EMAIL PROTECTED] All of this is for nothing if we don't go to the stars - JMS/B5 To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-current in the body of the message
Re: Dangerously dedicated yet again (was: cvs commit: src/sys/kern subr_diskmbr.c)
+---[ David W. Chapman Jr. ]-- | : IBM DTLA drives are known to rotate fast enough near the spindle | : that the sustained write speed exceeds the ability of the controller | : electronics to keep up, and results in crap being written to disk. | | | I would adssume it actually the tracks FURTHEREST from the spindle.. | | | Wouldn't the linear speed be faster closer to the spindle at 7200 RPM | than at the edge? er no. The circumference of a circle is 2 PI r. So as your distance from the spindle increases the amount of physical real estate you're traversing increases. Since you are turning at a constant angular velocity, your linear velocity increases as the distance from the spindle increases by a factor of PI (or around 3 if you're not a maths person). Even been at one of those carnivals where they have a spinning thing? It's easier to stay near the centre, than near the edges, because you are moving a *lot* quicker at the edges. And just for the hell of it; If you have a 3 unit disc doing 1 RPM If you're 1/2 unit out you're doing ~3 units/sec If you're one unit out, you're doing ~6 units/sec If you're two units out you're doing ~12 units/sec at three;~18 units/sec Multiply by 7200 and s/units/inches/ The outside of your disk is really moving The density of the sectors at the outer edge is lighter than near the centre, which mitigates the speed some what. See Also: artficial gravity in space stations/ships/objects -- Totally Holistic Enterprises Internet| | Andrew Milton The Internet (Aust) Pty Ltd | | ACN: 082 081 472 ABN: 83 082 081 472 | M:+61 416 022 411 | Carpe Daemon PO Box 837 Indooroopilly QLD 4068|[EMAIL PROTECTED]| To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-current in the body of the message
Re: Dangerously dedicated yet again (was: cvs commit: src/sys/kern subr_diskmbr.c)
On Sunday, 9 December 2001 at 22:44:52 -0800, Peter Wemm wrote: 3) You get a system lockup when booting the *computer* if *any* DD disk is attached anywhere at all. This is what killed the Thinkpad T20*, A20*, 600X etc. After all the yelling we did at IBM, it turned out to be FreeBSD's fault. It also happens on Dell systems. It kills all IA64 boxes if a FreeBSD/i386 disk is attached anywhere. What are you talking about? The IBM lockup was due to the presence of *Microsoft partition* of type 0xn5, for any value of n. If these systems also lock up with a dedicated disk, it's due to some other bug. Greg -- See complete headers for address and phone numbers To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-current in the body of the message
