taint.org: Justin Mason’s Weblog

I’ve been running into problems recently (since several months ago at least), with USB hardware on my Thinkpad T40 running Ubuntu Hoary Dapper; in particular, every time I plug in my iPod or one of my USB hard disks nowadays, I get this:

[5008549.187000] usb 4-3: USB disconnect, address 14
[5008550.143000] usb 4-3: new high speed USB device using ehci_hcd and address 18
[5008552.643000] usb 4-3: new high speed USB device using ehci_hcd and address 27
[5008557.393000] usb 4-3: new high speed USB device using ehci_hcd and address 43
[5008557.893000] usb 4-3: new high speed USB device using ehci_hcd and address 44
[5008558.643000] usb 4-3: new high speed USB device using ehci_hcd and address 46
[5008558.895000] ehci_hcd 0000:00:1d.7: port 3 reset error -110
[5008558.896000] hub 4-0:1.0: hub_port_status failed (err = -32)
[5008559.893000] usb 4-3: new high speed USB device using ehci_hcd and address 48
[5008562.643000] usb 4-3: new high speed USB device using ehci_hcd and address 58
[5008563.143000] usb 4-3: new high speed USB device using ehci_hcd and address 59
[5008563.643000] usb 4-3: new high speed USB device using ehci_hcd and address 60
[5008570.143000] usb 4-3: new high speed USB device using ehci_hcd and address 85

This repeats ad infinitum until the USB device is disconnected.

I had this down as a hardware issue (since it started happening just after warranty expiration ;), but some accidental googling revealed several other cases – and a workaround:

sudo modprobe -r ehci-hcd

Run that repeatedly, each time replugging the device and monitoring dmesg via watch -n 1 ‘dmesg | tail’ in a window, until the device is finally recognised as a USB hard disk. It generally seems to take 3 or 4 attempts, in my experience.

This LKML thread suggests hardware changes can cause it, but this hardware hasn’t changed in years. Annoying.

Anyway, this is ongoing. This tip seems to help, but it might be just treating a symptom, I don’t know — just posting for google and posterity… and to moan, of course :(

Tags: bugs, disks, ehci-hcd, hardware, ipod, linux, storage, usb

Keith Dawson sent this on — an interview with Jim Gray, head of Microsoft’s Bay Area Research Center and winner of the ACM Turing Award, talking about new transmission systems for truly massive data collections. Very interesting:

[One] option is to send whole computers. …. We’re now into the 2-terabyte realm, so we can’t actually send a single disk; we need to send a bunch of disks. It’s convenient to send them packaged inside a metal box that just happens to have a processor in it. I know this sounds crazy — but you get an NFS or CIFS server and most people can just plug the thing into the wall and into the network and then copy the data.

Dave Patterson, interviewer: What’s the difference in cost between sending a disk and sending a computer?

JG: If I were to send you only one disk, the cost would be double – something like $400 to send you a computer versus $200 to send you a disk. But I am sending bricks holding more than a terabyte of data — and the disks are more than 50 percent of the system cost. Presumably, these bricks circulate and don’t get consumed by one use.

DP: Are you sending them a whole PC?

JG: Yes, an Athlon with a Gigabit Ethernet interface, a gigabyte of RAM, and seven 300-GB disks — all for about $3,000.

DP: It’s your capital cost to implement the Jim Gray version of “Netflicks.” (jm: sic)

JG: Right. We built more than 20 of these boxes we call TeraScale SneakerNet boxes. Three of them are in circulation. We have a dozen doing TeraServer work; we have about eight in our lab for video archives, backups, and so on. It’s real convenient to have 40 TB of storage to work with if you are a database guy. Remember the old days and the original eight-inch floppy disks? These are just much bigger.

DP: “Sneaker net” was when you used your sneakers to transport data?

JG: In the old days, sneaker net was the notion that you would pull out floppy disks, run across the room in your sneakers, and plug the floppy into another machine. This is just TeraScale SneakerNet. You write your terabytes onto this thing and ship it out to your pals. Some of our pals are extremely well connected — they are part of Internet 2, Virtual Business Networks (VBNs), and the Next Generation Internet (NGI). Even so, it takes them a long time to copy a gigabyte. Copy a terabyte? It takes them a very, very long time across the networks they have.

Tags: bandwidth, disks, fedex, jim-gray, ms-research, shipping, sneakernet, storage, terabytes, ups

Tech: This is the second entry talking about ‘Life Hacks’. Possibly the best tip I came away from the talk with, is this one:

All geeks have a todo.txt file. They use texteditors (Word, BBEdit, Emacs, Notepad) not Outlook or whathaveyou.

What we keep in our todo is the stuff we want to forget. Geeks say they remember details well, but they forget their spouses’ birthdays and the dry-cleaning. Because it’s not interesting.

It’s the 10-second rule: if you can’t file something in 10 seconds, you won’t do it. Todo.txt involves cut-and-paste, the simplest interface we can imagine.

It’s also the simplest way to find intercomation. EMACS, Moz and Panther have incremental search: when you type a “t” it goes to the first mention of “t”, add “to” and you jump to the first instance of “to”, etc.

Power-users don’t trust complicated apps. Every time power-geeks has had a crash, s/he moves away from it. You can’t trust software unless you’ve written it — and then you’re just more forgiving. Text files are portable (except for CRLF issues) between mac and win and *nix. Geeks will try the Brain, etc, but they want to stay in text.

I was already doing this, having learned the latter lesson ;), but I was making one mistake — I was trying to keep the TODO.txt file small by clearing out old stuff, done stuff, and cut-and-paste snippets of command lines, and by moving things into files in ’storage’ directories.

That doesn’t work. You think you’ll be able to grep for it later, but you’ll have forgotten what to grep for. You’ll even have forgotten what storage directory you used. The solution is to keep it all in one big file, and use i-search. That really does work.

In fairness, I actually have two files of this type. One is the “real” TODO.txt. But the other is a GPG-encrypted file containing usernames, URLs, passwords, nameservers, VPN settings, etc. I have a feeling this is another common Life Hack idiom, too…

Another great tip in the same vein, from JWZ — make an /etc/LOG:

Every machine I admin has a file called /etc/LOG where I keep a script of every system-level change I make (installing software, etc.) I rsync these LOG files around (keeping redundant copies of all of them in several places) so that if/when I need to re-build a server from scratch, it’s just a matter of following the script.

This has been working out great (when I remember to do it. Discipline! ;)

Tags: emacs, file, grep, storage, stuff, tech, text, tip, todo, txt, type