USB KVM RFI: Final Followup
Posted: November 14, 2010 Filed under: Computers and Internet Leave a comment »This, I hope, is the final followup to my USB KVM interference problem. I thought I had fixed it, but no. That decorative nameplate was indeed just decorative.
I tightened all the screws on my Tyan server board and the problem seems to have disappeared. The nameplate on the KVM fell off, again, so out with the hot-melt glue gun.
Followup: VGA RFI via KVM
Posted: September 27, 2010 Filed under: Computers and Internet Leave a comment »Following up on my last post, the interference recurred and I got pictures. I was watching a YouTube video here. My resolution is 1600×900, below the native resolution for this LCD for reasons I’ve gone over before. This example has a regular sine-wave like quality with what appears to be at least two frequency components.
And browsing Flickr: Though there are considerable moiré artifacts in this shot (the purple and green patches—ignore them, the screen is fine), the RFI shows up nicely in the “From” text, particularly the F.
I’ll have an update when I get my filter parts in a few weeks. I’ll bet there are a number of people with KVM’s who may have seen symptoms like these and not realized it.
This Hot Server
Posted: July 23, 2010 Filed under: Computers and Internet Leave a comment »Just weeks after having my workstation die, I had another problem: Heat. My building gets hot. It’s well insulated and there were new windows installed a few years ago. We have also had many 90 °F days with 70 °F dewpoints. Not fun. During renovations to my part of the building last year, a neighbor upstairs from me told me of all the window AC’s he cooked from the sun.
An alert from my system management program, at midnight local time, tells the whole story:
2010/07/19 04:00:11(UTC) Email(First) CPU Temp: Reading(86.000C), Status(>= upper critical threshold) PINKY(192.168.10.5)
86° C.
Yikes!
This server has a troubled history: It was SATV’s first server, and as I related before, it was cheaply built and defective from the start. I got it in 2002 and it has been totally gutted. Nothing is left from its past. It’s currently running a Tyan S3950 AMD-based server board with a dual core Opteron 1224SE, 8G of RAM, ServerWorks chipset, Intel NICs, and a HighPoint 1742 SATA RAID controller with two 1TB Western Digital drives.
Except for the time the CPU heatsink frame broke, it has been trouble free, though there are BIOS bugs that affect virtualization (I’ve never been able to use that on this board) and thermal management (no CPU throttling). The chipset drivers were orphaned since Broadcom sold off its ServerWorks line right after I bought the board, so 64-bit support has not been what it could be.
It’s that bit about thermal management that I’ve been having problems with. I have not actually had my server lock up from the heat but it is a constant worry. Besides, I am conditioned, from being long in IT, to obsess over every watt of power that goes in and every watt of heat going out. I don’t really need another space heater under my workbench.
I want to get a new server board and would love a new Chenbro case but unexpected expenses…well, I have to live with this a bit longer.
All I could reasonably do with little money was to put in more fans in the case. My server’s case is large enough. Unfortunately, it was designed in the mid-90′s when CPU’s didn’t get as hot as they do now. The only cooling in the front of the machine is a small fan and an impossibly small air vent in the front.
As in many machines, the front card slot holder is used to mount the fan (and also the PC speaker, which has been taken out–the Tyan has an onboard sounder.) There are virtually no full-length cards in use, at least I have never seen any.
It’s possible I could put a bigger fan in and remove the slot holder but I have no larger fans in stock so I’m deferring this. But the air intake is a bigger problem.
That’s it. That’s the air intake.
I was also having trouble with dust bunnies. They would set up nice dust bunny condos inside my server if I let them. It didn’t help that my house vacuum cleaner was failing for months before I noticed and got a higher-powered Hoover. I was on MCM Electronics, trying to fill up an order to get the free shipping when I found a filter frame on clearance.
I had some more fans lying around.
They’re three-wire fans, unfortunately, the third wire is not compatible with most motherboards–it is used for the thermistor sensor, rather than the tach as in most fans so they will just be wired into the power supply without any management.
After too much work I cut this vent hole in the front bezel and mounted the filter.
And mounted two fans in back for exhaust.
I would really like to replace the front fan with one that has more airflow. I do expect the dust bunnies will have to find another place to set up shop.
Temperatures on the system board seem to be around 55-62C since I did this project, acceptable for a machine with two hot Western Digital RAID drives in it, but there haven’t been any really hot days since the work was done.
If I get through the rest of the summer with this, it is a win. Just so long as I can run the SBS 7 beta with it, I will be satisfied.
OMG! The Plaid Screen of Death is real!
Posted: August 9, 2009 Filed under: Computers and Internet Leave a comment »
I loved making this joke, but I found a true plaid screen of death from Lyllybell!
plaid screen of death
http://mediaservices.myspace.com/services/media/embed.aspx/m=38960049,t=1,mt=video
That is a seriously, seriously messed up video card! A fault that would affect real-mode graphics like that indicates a bad video card or just one that is seriously incompatible. The poster says it’s a new server.
Bug in nVidia 3D Stereoscopic Glasses support
Posted: August 9, 2009 Filed under: Computers and Internet Leave a comment »Heads up from Within Windows: If you are running nVidia video drivers in Vista or Windows 7, you may see this problem. A handle leak in nvSCPAPISvr.exe, the nVidia Stereoscopic 3D Driver Service, may cause performance problems.
In my case, it also kept me from installing a new copy of VirtualBox on my Vista machine; the install would fail. Process Monitor showed sharing violations whenever the VirtualBox driver installer tried to access INF files. Running Handle on the INF file being blocked showed it was held by nvSCPAPISvr.
I didn’t connect it to the stereoscopic display service until I saw Rafael’s post. His use of Process Explorer to find the leak and his disassembly of the service code is a quintessential example of problem diagnosis worthy of Russinovich.
This bug can result in over 100,000 handles being leaked: I think I have the record—I have 148,420 handles leaked by that service, as you can see in the screenshot above.
Some have reported performance problems. I didn’t notice anything. But if you install new drivers for unrelated devices on your machine, the installs may fail, possibly catastrophically as one commenter in Rafael’s blog noted.
Workaround: Stop and disable the Stereo Service. I have 20/200 vision in my left eye so I have very poor depth perception and 3D displays are useless to me. I won’t miss it.
Linux and People with Disabilities
Posted: February 9, 2009 Filed under: Computers and Internet Leave a comment »Eric S. Raymond, famous Linux personage, wrote a post on his blog that reminded me of my old blog postings of a year ago, Why SATV doesn’t use Linux Part 1 and Part 2. Raymond was writing about Linux Hater’s Blog, but there was a very interesting thread in the comments that I will quote:
esr Says:
November 18th, 2008 at 4:08 am>If you’re going to criticize people like him who write off hackers as “freaks and geeks”, I think it’s only fair for us to retire terms such as “lusers” and “room-temperature IQ”.
Huh? How does that follow? I could pity a blind person while still thinking that Braille accessibility is tremendously important. That’s a hypothetical; there aren’t actually enough blind people to make Braille accessibility much more than a feel-good checkbox item in the larger picture. [Emphasis added-DM] My point is you’re confusing two separate issues here. They’re related only in that you can’t successfully evangelize to an audience you pity or despise, it tends to leak through in your presentation and turn them off.
Note that point of ESR’s, I’ll come back to that. Continuing the thread, a blind user weighs in:
David Says:
November 18th, 2008 at 2:52 pmESR: interesting (though not altogether surprising) to see you consider accessibility secondary and basically a PR issue. As a blind computer user (and no, this is not identity politics, I don’t define myself that way but it is obviously part of who I am) it’s also interesting to note that the best I can expect from you is pity. Fortunately the accessibility situation in gnu/linux is driven by people who think it more than a feel-good checkbox, thus orca, emacspeak, BRLTTY, and some other very capable accessibility solutions. I’d also point out that accessibility, as a rule, runs together with good design, since an application that can be interrogated about state by an accessibility aid is an application that can be interrogated about state for any other purpose (testing, use as the back-end of a bigger process, etc).
Obviously no one is obliged to care about accessibility, nor to have any particular attitude with respect to blind people (or anyone else). I’d just say though, that pronouncements like that make it rather difficult for me to advocate for free software inside the blind community. Oh well.
ESR responds:
esr Says:
November 18th, 2008 at 8:41 pm>As a blind computer user (and no, this is not identity politics, I don’t define myself that way but it is obviously part of who I am) it’s also interesting to note that the best I can expect from you is pity.
You need to work on your reading comprehension. I spoke of ‘pity’ only in a hypothetical.
It is true that I put accessibility for blind and handicapped people relatively low on my priority list; that’s because there are much larger populations, with more influence on demand patterns, that we haven’t got the hang of writing for yet. When planning for victory, you have to plan for victory, not just for small gains that will make you feel good.
David:
David Says:
November 19th, 2008 at 7:13 amESR: OK, I understand your remark to be hypothetical. For whatever reason I understood the hypothetical to refer to the other clause (as in, caring about accessibility is hypothetical but pitying blind people is actual). My reading comprehension is greatly aided by less ambiguity.
As to the tactical issue, it can be argued both ways. I think demand patterns of public entities are going to be somewhat affected by the accessibility situation (not speaking of blind people here specifically). In addition, life expectancy keeps going up, so we can expect more disabled people (maybe medicine will fix this in the future, but maybe not). To close, accessibility, like security, tends to be problematic when bolted on. It’s the kind of thing that is usually cheaper to design in advance. The good thing about Unix philosophy is that it tend to be conducive to such designs, given the tendency to separate processing from presentation, and the desire to make things automatable. So far I’m pretty sure gnu/linux is the only OS that can be installed from scratch by a blind person, for instance, without help. Not sure about macs.
ESR:
esr Says:
November 19th, 2008 at 7:36 am>To close, accessibility, like security, tends to be problematic when bolted on.
That’s an interesting point. I don’t think your argument about increased life expectancy is sound – blindness and motor impairment may happen as complications of age-related diseases, but they’re not common enough to make the impaired population much larger relative to the general population of oldsters. You’re still competing for UI design time against a much larger group of people who have good visual acuity and fine motor control; their desires, e.g. for better-tuned visual interfaces, have to come first if our goal is to win market share.
On the other hand, you’re clearly right that accessibility can’t be painted on, and that making GUIs accessible to the blind is especially problematic (I have given related issues some thought in connection with my unfinished The Art of Unix Usability).
My first thought on The Art of Unix Usability was incredulity, to put it very politely. Unix was never ever ever designed for "usability” for its original audience of developers never mind Aunt Tilly. It would be too cruel for me to elaborate further.
But not about ESR’s opinions on access to his “product” (open source Unix) for people with disabilities. I’m very disappointed, but not particularly surprised.
People with disabilities (of which I am sadly one) are exquisitely aware of the “tyranny of the majority”. Let me quote ESR again: “You’re still competing for UI design time against a much larger group of people who have good visual acuity and fine motor control; their desires, e.g. for better-tuned visual interfaces, have to come first if our goal is to win market share.
This is the open-source community’s response to that old old PSA you may have seen if you’re old enough, the one with the school administrator who tells parents of a special-needs child, “We can’t accommodate you for just one child!”
Linux can’t accommodate just one blind user!
An even crueler irony is that ESR almost gets it: “On the other hand, you’re clearly right that accessibility can’t be painted on…”
No bleep. Accessibility to the disabled in modern GUI’s is nothing more than exposing the mechanisms of the interface to third-party applications so that they can present the desired information in large text, speech, captions, Braille or whatever the user with a disability might need. Not to mention input from voice recognition programs, special keyboards and sip/puff interfaces.
You sure can’t bolt that on after the fact.
I’m not sure the bazaar of Eric’s, The Cathedral and the Bazaar, is concerned with people with disabilities, other than the obligatory response, “Well, if you want it, write it from scratch yourself!”.
The only reason Linux has accessibility features is because Sun developed Orca, the screen reader/speaker/assistive technology software that’s in many distros, notably Ubuntu. Sun. A commercial concern. A Cathedral, rather than the Bazaar.
Companies like Sun, IBM and Novell know full well the desktop solutions they sell to enterprises must be usable by many different users, including those with disabilities. It’s the law in the US.
Imagine a very experienced accountant working for your firm. She’s been in a car accident and detached her retina and lost the use of her good arm.
Do you want to tell her, “Well, most people don’t have your problems.” “There’s a much larger group of people who have good visual acuity and fine motor control“.
That could get you sued.
Even if you don’t advocate litigation (I don’t), it’s hard not to be insulted by this unfairness. Most people who encounter friends, family and co-workers with disabilities would try to help and not be that impersonal.
Eric, what do you say to Aunt Tilly?
Weird Display Artifacts With Vista Aero
Posted: June 17, 2008 Filed under: Computers and Internet Leave a comment »Notice the ghosted text in the upper center. It was caused by Movie Maker crashing the night before. The artifact persisted until the system was rebooted.
DVD-ROM Causes Crash
Posted: October 11, 2007 Filed under: Computers and Internet Leave a comment »Ed Bott recounts a weird case: New machine throws bluescreens. Not so weird, you’d think, except for the cause: A bad DVD-ROM.
Random Windows errors? Check the hardware. | Ed Bott’s Windows Expertise |
Excellent Russinovich post : The Case of the Failed File Copy
Posted: October 2, 2007 Filed under: Computers and Internet Leave a comment »Mark Russinovich, one of my very favorite Windows experts, posted another excellent blog entry, "The Case of the Failed File Copy". It’s a great example of how Windows file system abstraction, normally a great thing, can kick you in the ass at the wrong moment.
We think of the old FAT12 and FAT16 filesystems as being outdated, but they are still very much in use in digital cameras, PDA’s, and MP3 players. Virtually every SD or micro SD card you pick up has a FAT filesystem, as do the vast majority of USB sticks. (I’m certain that’s all of them, since I have yet to see a USB device formatted as NTFS!)
There is no other "common" filesystem in the world but FAT. This has caused me grief in transferring video files between PC’s and Macs since the only common format is FAT32 and it cannot create files larger than 2 gigs. (By the way, Microsoft may have thrown a very misleading error message in this situation, but Apple, sadly, is no better. All sorts of file copy errors and SMB protocol errors seem to result in an "error -35". Much fun to figure out.)
Microsoft’s new filesystem, exFAT, to be in Vista SP1, promises to resolve these issues at least in part, but I’m not hopeful for it to be included in the next version of OS X after Leopard.
Microsoft should just make virtue out of necessity and relax the licensing for FAT or even open it up completely, since it is already so ubiquitous.
Google Book Search becomes accessible
Posted: July 9, 2007 Filed under: Computers and Internet Leave a comment »Excellent news for people with visual impairments who read books online. Google Book Search has added accessibility features so these people can read more books!
I’ve been visually impaired myself for all my life. When I had retinal surgery a few years ago and was trying to save my sight, the only books I could read were either on my Palm Tungsten or through the excellent NewsAloud RSS newsreader. Things are much better these days but I’ve always set my machines to show much larger text than most people would use, and I use my PDA (now a Windows Mobile iPaq) very heavily for ebooks.












