Let me try to articulate what I’m looking for when I say “component system” (perhaps something more nebulous than “content management system”).

• Obviously I want to divide my game into components that implement defined interfaces. For example, there’s a component that handles the network communication with players, another that handles streaming the game events to “observers” (people that watch but do not participate), a component to handle physics, a component to perform (for example) validation on incoming player commands, etc.

• I want to define dependencies between components. These dependencies are then used to acquire a suitable implementation of the component’s interface.

  For example, when I start the game maybe I “start” the front end component that handles communications with player; lets call that the “player server.” Now, the player server generates events such as “player connected,” “player moved,” etc. Somewhere (in code, or maybe even in something like ZCML) I’ve defined that this implementation of the component needs a component implementing IPlayerEventConsumer. The component system then finds (using my configuration) an implementation for that interface and makes it available to the player server.

• Assuming my components are written correctly, I want to be able to have a component execute in the same thread as other components (e.g. in the “main thread” as a microthread/coroutine), or in a new thread, or in a new process. For example, if I have lots of CPU-intensive physics code, maybe I want to run that on another processor, so I need threads. Of course, maybe I’m running on CPython, where I might need separate processes to bypass the GIL (ignoring for the moment the question of efficient IPC). Or maybe I’m working with something like a GUI where I need to have that run in a separate process (of course, doing a GUI can cause even bigger headaches).

• I want the ability to implement components in other languages (see also: component executes in separate process, above). This means I want a standard protocol for communication between components. XML-RPC comes to mind. Something else easy enough to implement comes to mind. There’s things like pickling in Python, but I don’t know how much fun that would really be to implement in a non-Python language; maybe something more language-agnostic?

  For fun, I’ll add here that I might like to be able to communicate with components using a variety of methods: pipes, Unix sockets, TCP/IP, and so on. This is desirable.

Now, I think I’ve just described a billion other attempts at “component systems”: COM/DCOM, maybe EJB, CORBA, maybe KDE’s DCOP. Let me add a couple more requirements that should narrow the field a bit:

• The “component system” must be platform-independent–or at least support including Linux, *BSD, OS X, and Win32 (actually, I could give up Win32 if I had to).

• I want the component system to be mostly transparent to me, the coder. I expect to have to configure the bindings between interfaces and implementations, specify dependencies, configure the manner in which a component will execute (microthread/thread/process; subject to the “execution style” the component is prepared to run in), and configuring the location (e.g. host/port) of other components in the system. I don’t want to have to manually write up a proxy class for a remote component, for example. As much as is humanly possible, I don’t want my code to care whether a component is running in shared memory or on a box 1,000 miles away.

COM/DCOM is basically going to be Windows, right? DCOP might not be, what with KDE 4 supposedly running on Windows (right?). EJB has notorious boilerplate (though it has been a while for me), when I think CORBA I think IDL, etc. Those aren’t “mostly transparent.”

Kamaelia looks interesting. The system of “wiring” components together feels right to me; I was first exposed to this in NesC. However, the implementation needs to be updated to support the new features of generators in Python 2.5, as the current syntax strikes me as rather ugly. In fact, it looks like Kamaelia needs a recent release, period: the last one I saw was from 2006.

(As a side note: everything should be easy_installable. Kamaelia and Twisted are not, though Twisted has ongoing work to this end.)

Kamaelia also fails to offer multi-process operation, as far as I can tell (you could write it yourself without too much pain), and it needs a way to generalize its “wires” to support communication with, e.g., remote components. You could actually combine the marshalling component with the framing component and a TCP client/server components and make this work; but that might have shot straight past “configuration” into “programming.”

Twisted is a much, much, much larger framework than I ever realized, and a lot of it seems pretty good. Nonetheless, the centerpiece of Twisted (if you believe the docs) still seems to be their “reactors” which require you to handle concurrency by defining things like Protocol subclasses that receive event messages (i.e. method calls) like connectionMade and dataReceived. This programming model might feel a little strange. They’ve got this neat looking inlineCallbacks decorator, which looks like it might lend itself to a coroutine kind of style. Then you start to realize that you’re not sure what you can use it for. I actually started writing something like:

class HelloWorldProtocol (LineReceiver):
def connectionMade(self):
    self.transport.write("Hi, who are you?\n")
    # Now I'll read their name:
    line = yield self.readLin  # ... hey, uh, there isn't a read method

I’ve seen several IRC logs where people try to figure out similar things. For what I’m doing, inlineCallbacks doesn’t seem like something I’m going to be able to use much.

I’ve considered building something like Kamaelia’s style of wiring up components inside Twisted. Twisted has some kind of support for things like processes and threads. I haven’t determined if these really meet my needs, and I keep reading scary things about them being deprecated.

If you believe Twisted’s finger tutorial they’ve also drank the “Zope Component Architecture” Kool-Aid, though thankfully I didn’t see any ZCML (yet…). Look at the final product of that tutorial and notice all the interfaces and “adapters” flying around. I don’t really feel like I gain enough for that extra code.

The question I ignored earlier, the one of performance, is still outstanding in my mind: can this kind of system be done [in Python] efficiently? I’m afraid I’m dreaming of a “component system” that’s going to be so slow as to be unpractical.

And, finally: do I really need these features?

Apparent side-effect of running sudo kino: some shared memory used by dmix became owned by root and mod 0600. Thus when you run something like, say, aplay (ALSA configured to use dmix by default), you get “unable to create IPC semaphore” (among some other lines).

My fix:

1. grep ipc_key /etc/alsa/*. In my case, I see something like /etc/alsa/alsa.conf:defaults.pcm.ipc_key 5678293 (that’s 0x56a4d5).
2. ipcs -a and look for the IPC key in hex. I had both 0x56a4d5 and 0x56a4d6. I… hope 0x56a4d6 belonged to ALSA because…
3. First I made sure that the nattach column said 0 for any dmix-related segments/semaphores, then
4. I used ipcrm -M 0x56a4d5 (and then ipcrm -M 0x56a4d6) to delete those shared memory segments, and ipcrm -S 0x56a4d5 to delete the semaphores (“Semaphore Arrays” is the heading; maybe simply saying “semaphores” is poor form on my part).

Then audio worked.

I am more and more looking forward to Fedora 8 and PulseAudio.

1. Search Google for “sound forge equivalent for Linux.”
2. Find several references to “Wave Forge.”
3. Find “Wave Forge” hasn’t been updated this century. Move on.
4. Decide to try Audacity because it’s in the back of your head, and Ardour because you found a bunch of links to it somewhere.
5. yum install audacity ardour. That was easy.
6. Run Ardour. Tells you it needs JACK. WTF is a JACK? Move on.
7. Run Audacity. Loads. GUI looks a little silly compared to Sound Forge, but it looks functional enough.
8. Try to load the MP3 file. Get told this version doesn’t have MP3 support.
9. Fish around for something to decode an MP3 to a WAV file. Feel bad about considering installing xmms just because you remember how to do this with WinAmp. Rejoice when you find lame --decode.
10. Load the WAV in Audacity. Looks good.
11. Hit the play button. Get told there’s an error in sound output.
12. Check sound preferences. Note that there are no available playback devices.
13. Read around for a while about JACK. See references to jackd. Eventually realize that this is something you need to run yourself, as your own user.
14. Run jackd. Get told that it can’t open the hardware device, presumably because other things (Amarok, Flash) are using it.
15. Find the correct invocation to run jackd which is something like jackd -d alsa -d default (-d twice, WTF).
16. jackd seems to keep running. Cross fingers, run Ardour. It opens.
17. Look at the Ardour interface. Decide that (1) it’s not what I want, and (2) dear god that is ugly. Is that Tk? Motif? Holy hell. Run away.
18. Open Audacity back up for the shit of it. Lo, there is some sort of JACK playback device now. Select it, hit OK.
19. Click play button in Audacity. Error with sound card.
20. Go into settings, change record device from OSS to JACK. (But I’m not recording?) Click play button in Audacity. Sound comes out! Rejoice.
21. Select a section, figure out how to zoom in. Click play. Get an error telling you it can’t play.
22. Try playing different selections, no selections. Keep getting the same error.
23. Restart Audacity. Same error.
24. Restart jackd. Restart Audacity. Same error.
25. Read about qjackctl being very helpful. yum install qjackctl. That was easy.
26. Run it. Not sure what I’m looking at. Says JACK is started. Try to turn on logging. Tells me I have to restart something. Whatever.
27. Restart Audacity. Hit play. Same error.
28. strace jackd. Hit play in Audacity. No activity.
29. Stop jackd and tell qjackctl to start it. Get a pretty incomprehensible error message in its “log.”
30. Realize that it’s bitching because it’s trying to start it with real-time priority, which it presumably doesn’t have permission to do.
31. Read http://jackaudio.org/faq. “The simplest, and least-secure way to provide real-time privileges is running jackd as root. This has the disadvantage of also requiring all of JACK clients to run as root.” Yeah, no.
32. Google around a bit, find out about /etc/security/limits.conf. Find some lines in there referring to @jackuser.
33. Try to usermod -a -G jackuser myuser. Fails, presumably because my user is in LDAP (but the group is in /etc/group).
34. vigr, add myself to the jackuser group by hand.
35. Don’t want to restart my X session to get new groups. Figure I need to log in from scratch to get new limits. Fuck it, ssh localhost.
36. Run qjackctl. Tell it to start jackd. Works. Rejoice.
37. Run Audacity. Hit play. It works!
38. Stop. Hit play again. It still works!
39. Stop. Make a selection. Play the selection. Holy shit it played the selection!

Really not very much work at all. And Audacity only crashed, like, three or four times while I was using it! (Mostly when hitting the play button to play the section I was working on. I can’t remember if jackd exited too.)

I can’t wait for PulseAudio. I’m sure that will make all of this even easier.

Oh, but in the end, I just ended up using sox and normalize in a script to do my MP3s in a batch…

I did hit a few gotchas though:

• Like I said above, don’t forget to restorecon -Rv on the restored files if you’re on a system with SELinux enabled.
• If you have mailboxes, particularly folders underneath the inbox, you may need to invoke reconstruct with -p default. This registers them in mailboxes.db, I guess? It makes them show up in lm from cyradm which can’t be bad.
• Related to the above, I don’t think reconstruct will believe a directory is a mailbox unless there is a cyrus.header file in it. Just touch cyrus.header was enough for me. (I was calling reconstruct -p default -xrf BTW; I don’t know if, for example, -x makes it rewrite cyrus.header to have valid/meaningful contents. It should be non-empty, I believe.)
• Finally, Courier’s messages all just used a line feed for line endings. Cyrus demands DOS-style CRLF for line endings. Symptom for this: bringing up the message index (in Mutt, at least) goes much, much slower than it should. I believe this happens because too much information gets put in the Cyrus header/cache files. (Use the mbexamine program and you’ll see lots of weird information in the “headers” I think.) Fixing this for me was as simple as running unix2dos over the files (and then fixing permissions; I should have done sudo -u cyrus unix2dos [0-9]*. instead of just running unix2dos as root.)

Oct 29 17:15:52 gateway lmtpunix[26948]: sieve runtime error for
someone@example.com id <blahlblahasdlahd@as987da97da987ads7>:
Vacation: Sendmail process terminated normally, exit status 75

Nov  1 00:47:10 gateway lmtpunix[30206]: FATAL: couldn't exec() sendmail

Explanation: SELinux is preventing Cyrus from running sendmail.

Solution:

1. Install the selinux-policy-devel package.

2. Jam this in local_cyrus.te:

   policy_module(local_cyrus, 1.0.3)
   
   
   require {
           type cyrus_t;
   };
   
   
   corecmd_exec_sbin(cyrus_t)
   mta_send_mail(cyrus_t)
   

3. make -f /usr/share/selinux/devel/Makefile local_cyrus.pp

4. semodule --install local_cyrus.pp

Now Cyrus should be able to run sendmail.

WARNING: this may allow Cyrus to do more than it should be able to. I’m hardly an SELinux expert.

In this case, these guys aren’t currently Outlook/Exchange users, and obviously Exchange doesn’t fit the definition of “cheap,” so I don’t have to contend with that. Here I’m referring to the difficulty switching away from Outlook/Exchange, which generally boils down to:

1. Useful features that are available in Exchange but not generally available in competing FOSS products. A few years ago lots of products were missing free/busy information, which was often a deal breaker. (Today many packages seem to have this, but certainly not all of them.) Other things might be the slick web interface that is Outlook Web Access (as long as you’re in IE), integration with Windows Mobile and Blackberry (well, with BES at least) devices.

2. People generally like Outlook, or at least hate it less than other things they’ve used. It’s consistent with another fixture in most businesses, Microsoft Office. It’s got a variety of software available for it and software that integrates with it (particularly… Microsoft Office). It’s also prettier than a lot of the competition.

I’m loathe to say Outlook/Exchange is good, precisely. Were I to try to start using Outlook I expect I’d find a number of things to hate about it, and I know of many occasions when administering Exchange was a bitch (for example, crashing with no explanation for why (inadequate logging, that is), or MTA features that Exchange should have). The fact remains, however, that for businesses invested in Microsoft Windows and Microsoft Office, and putting aside the issue of cost, you could do a lot worse than Outlook/Exchange. The two products offer useful features still not found in most FOSS products (at least, not all in the same product).

So it’s a good thing I don’t have to contend with that. (My own personal biases aside, normally I would probably suggest Exchange, in the interests of my client. In this particular case, their budget rules it out.)

Moving on, I don’t know of a good product to suggest to them! That is, I’ve found several FOSS projects, which I’ll list below, but I have no idea which of them are even production quality, let alone stable, usable, and whether they will meet my client’s needs. I don’t have time to review them, so unfortunately I probably won’t be able to make a “recommendation” other than basically giving them this list.

This is not me asking for any help, really, though I welcome opinions on these various products I suppose. The real purpose of this post is to note the small amount of research I’ve done at this point, and to give me a list of products I can go back and check later when I have some time (laughter ensues).

Without further delay, the list of generally free and/or open source “groupware” I’ve found:

• Meldware Communication Suite: Java (immediate reaction: mmm, huge footprints and one million dependencies). looks like it includes an MTA, calendar server (think WCAP), and separately some sort of “web interface.” They have some 1.0… milestone releases?
• Citadel: this used to be BBS software, says Wikipedia? WTF? Nonetheless I’ve read several recommendations for it. Web interface supposed to be modern (read: AJAX) and pretty nice. I just don’t know if this is good for, like, scheduling meetings.
• OpenGroupware.org
• Open-Xchange: How free is it? I don’t know. I’m pretty sure they have at least some commercial (which is to say, proprietary and not free-as-in-beer) components. Been around for a long time.
• Scalix
• Zimbra: I don’t even really know if the calendaring here, my client’s major requirement, is even available, let alone useful for a business. Plus I’m still biased against Zimbra because the last time I tried to install from source was an incredible nightmare.
• Group-Office
• Horde Groupware: This is basically a nice distribution of the various Horde applications such as Kronolith, their calendaring software. This looks attractive to me, since they’re already using Imp for webmail. I’m also fairly certain Horde is going to serve as the web interface for Kolab (see below) which probably says that others find it to be a good interface and easy enough to integrate with.
• Kolab: I confess that I didn’t really look at these guys, since their web interface is still “experimental,” and I probably require that.
• Simple Groupware
• phpGroupWare
• eGroupWare
• Chandler: Is it usable now? Does it have a web interface? I have no idea.
• Google Calendar: They’ve got “conference room and resource scheduling” and free/busy information at least. I like Google Spreadsheet so far. I’m not sure if $50/year is totally unrealistic for my client’s budget or not.

So that’s the list of contenders I found. Since I had no real time to review/demo these products, I have no idea if some of them are unusable, defunct, or closed/proprietary/costly.

Now, I’m using FastCGI and Apache’s suEXEC to run the FastCGIs as particular (per-site) users. So for one site my configuration looks like:

<VirtualHost www.example.com:80>
        ServerName www.example.com
        DocumentRoot /srv/www/www.example.com/root

        SuexecUserGroup www_example_com www_example_com
        ScriptAlias /trac /var/www/suexec/www_example_com/trac.fcgi
</VirtualHost>

suEXEC (as distributed with CentOS 5) will only run things under /var/www, so I created /var/www/suexec. I want to run things as the example user, lets say, so I mkdir /var/www/suexec/www_example_com and chown that directory to example:example, because suEXEC requires that. Then I make a little .fcgi file that starts my FastCGI app (for Trac as you may have noticed).

So on and so forth; none of that is interesting. Now here comes SELinux: I did install the mod_fcgid-selinux package, which automatically installs an SELinux policy module for mod_fcgid (semodule --list | grep fastcgi). As far as I can tell, you must chcon -t httpd_fastcgi_script_exec_t your FastCGI scripts; without this, I believe your script won’t have access to various pipes or shared memory or something that it needs to communicate back to mod_fcgid living in Apache. Don’t label the whole directory httpd_fastcgi_script_exec_t, just the .fcgi file. See also the README.SELinux that comes in the mod_fcgid-selinux package.

At this point, especially since I had the SELinux httpd_unified boolean on (it’s on by default), I might have been in the clear. I go to run my trac.fcgi (via /trac)… and I get an internal error. /var/log/httpd/error_log spews HTML and other errors that sound generally like “I didn’t start as a FastCGI at all, here’s me as a regular CGI, whee!” The best part? No AVC messages.

Here’s where Dan Walsh’s post on disabling dontaudit rules comes in. As he says, the cool stuff is in Fedora 8 where all dontaudit rules can be disabled, even ones in policy modules (policy modules like the fastcgi module that is installed by mod_fcgid-selinux). However, in this case, and because I rebuilt fastcgi with no dontaudit rules, I can tell you the problem is in the base policy and not in a policy module; so using semodule -b /usr/share/selinux/targeted/enableaudit.pp works just fine to troubleshoot this.

So execute the above semodule command, restart Apache (for good measure?), reload /trac, and now we get:

type=AVC msg=audit(1190783371.758:8180): avc: denied { read write }
for pid=3 2127 comm="suexec" name="[180326]" dev=sockfs
ino=180326 scontext=user_u:system_ r:httpd_suexec_t:s0
tcontext=user_u:system_r:httpd_t:s0 tclass=unix_stream_socke t

type=AVC msg=audit(1190783371.758:8180): avc: denied { siginh }
for pid=32127 comm="suexec" scontext=user_u:system_r:httpd_t:s0
tcontext=user_u:system_r:http d_suexec_t:s0 tclass=process

type=AVC msg=audit(1190783371.758:8180): avc: denied { rlimitinh }
for pid=32 127 comm="suexec" scontext=user_u:system_r:httpd_t:s0
tcontext=user_u:system_r:h ttpd_suexec_t:s0 tclass=process

type=AVC msg=audit(1190783371.758:8180): avc: denied { noatsecure }
for pid=32127 comm="suexec" scontext=user_u:system_r:httpd_t:s0
tcontext=user_u:system_r: httpd_suexec_t:s0 tclass=process

Now, the last three messages are apparently no big deal. That first one, though, is the problem. So I run that through audit2allow, a little editing, and I come out with something like:

 policy_module(local_fastcgi, 1.0.0)

 require {
     type httpd_suexec_t;
     type httpd_t;
 };

 allow httpd_suexec_t httpd_t:unix_stream_socket { rw_stream_socket_perms };

(OK, sorry, that’s actually a significant bit of editing. I just learned about the macros that I guess you’re supposed to use, like policy_module. I found rw_stream_socket_perms in the fastcgi policy source.)

I slap that in a file like local_fastcgi.te then make -f /usr/share/selinux/devel/Makefile load (careful! I think that will build and install every policy in–and possibly every policy under–the current directory). Once loaded, I restart Apache, and now my FastCGI being run by suEXEC works.

I hope you didn’t just read this overly verbose post just to find “install the above policy module and FastCGIs running with suEXEC under CentOS 5 will work with SELinux on.” Er, sorry.

I would report this as a bug… maybe I should file it against EPEL, if they’ve got some bug tracking. Then they’ll probably end up pushing it upstream to the F7 maintainer? Which I assume is where the EPEL package was derived from. My question then is: does F7 have this problem too, or is it fixed in F7 by virtue of some other part of the policy?

The rule to dontaudit httpd_suexec_t getting at httpd_t:unix_stream_socket is actually in the core Apache policy, I think, and it seems to make a reference to how Apache should “close-on-exec.” So I’m really not even sure if this policy change should go into Apache’s policy (and have a bool?) or if it should go into mod_fcgid’s policy module (and have a bool there?).

So, does someone want to advise me as to where and against what package(s) I should file a bug? Or maybe I need to wade onto the Fedora SELinux mailing list?

They offer CentOS 5 now. (When we bought our last one, they only offered RHEL 3, which I had to remotely upgrade to CentOS 4.) When they turn the server over to you, you’ve got /, /boot, swap, and then /dev/sdb is one big partition. My task: change it to LVM on software RAID 1.

I don’t think their web site mentions it, and there was some question about whether they still offer it, but this newest server still has a Dell DRAC III card in it, which I needed to toy with grub (when I screwed up). You could probably do without remote console access, except (1) it will be hard to see errors, and (2) I don’t recall if grub has a functionality similar to lilo -R (“for the next boot only, use boot entry N”) these days.

Here are my rough steps to complete this task. This is based partly on what I did, partly what I should have done, and it’s all from memory (granted, memories that are scant hours old). Note that you probably don’t want to do this on a “production” machine (duh), as this will require reboots and potentially horking things. I did it on a fresh install that I wasn’t afraid to have reinstalled; you’ve been warned.

1. Partition /dev/sdb. For me, that’s 128MB /dev/sda1 as /boot, and the rest in /dev/sdb2. Both types 0xfd for RAID auto-detect. I set sdb1, which will be software RAID 1 for /boot, to be an “active” (AFAIK means “can boot off of here”) partition, in case sda1 fails.
2. Create the software RAID devices. For /boot, this like like mdadm --create -l 1 -n 2 /dev/md0 missing /dev/sdb1. missing is the word I always forget: it says “the disk that would normally go in this slot is… well, missing.” Repeat for /dev/md1 with /dev/sdb2.
3. pvinit, vgcreate, and then lvcreate all the logical volumes you want.
4. mkfs or equivalent on all your new devices. For the record, I found out RH’s anaconda does something like mke2fs -j -i <inode size> <device>. I left out the -i. Other options for mke2fs are apparently read from /etc/mke2fs.conf. After mke2fs anaconda seems to do tune2fs -i0 -c0 -ouser_xattr,acl -Odir_index <device>. (This is from memory, I hope it’s right.) Don’t forget to e2label everything too. RHEL 5’s mkswap apparently takes -L to set a label, which you can use in /etc/fstab.
5. Mount up your new, empty filesystem(s) somewhere. I made and used /mnt/sdb.

6. Edit grub.conf. Note on my system, /etc/grub.conf was not symlinked to the actual file, /boot/grub/grub.conf. If you see this I don’t see why you shouldn’t rm /etc/grub.conf && ln -s ../boot/grub/grub.conf /etc/grub.conf like I did.

   In grub.conf you want to make a copy of your currently booted stanza. In this copy, change the root (hd0,0) to be root (hd1,0), and also change the root=LABEL=/ in the kernel line to point at something like root=/dev/vgmain/lvroot (or wherever your root FS is).

   Also, for people like me on a DRAC III, you’ll want to comment out any bootsplash or hiddenmenu lines, you don’t need any serial console (I commented out both serial and terminal lines for GRUB and also removed console=... parameters to the kernel). You may want to bump up the timeout. Additionally, DRAC III users will need to add i8042.dumbkbd=1 to the kernel “command line.”

7. I don’t think this is necessary… but I did add (hd1) /dev/sdb to /boot/grub/device.map and I also re-ran /sbin/grub-install.

8. Copy everything from the running filesystems to the new filesystem(s). I used cd /; find . -xdev -print | cpio -pvdm /mnt/sdb/ to do this, and then the same with /boot. Jumping ahead some steps, after I finally got the new arrays booted, I don’t think this copied the SELinux labels right, which is no good. I encourage you to find a command that does copy the SELinux labels. Maybe star can help? Or cp -ax? If you use my method, go ahead and touch .autorelabel in the root of your new filesystem, which should cause SELinux relabelling at boot.
9. chroot to your new FS. mount /proc && mount /sys.
10. Edit /etc/fstab on the new FS to reflect your new layout. I note that a fresh CentOS 5 install using LVM on RAID doesn’t use LABEL=... syntax for selecting devices, so I’d put actual device names for everything on software RAID or LVM in column 1 of fstab. Note that I never got mkinitrd to run correctly (i.e. include the LVM stuff) as long as I was using LABEL=/ for my / partition.
11. This is kind of weird: I think you need the device nodes hanging around to ensure that mkinitrd works right in the next step, so run start_udev. The weird part: this is going to kill the running udevd and replace it with one whose / points to your new root. I was able to finish my work and reboot my system without udevd running on my real root; hopefully your mileage won’t vary.
12. If you’re using LVM like me, you need to run vgmknodes now, to make things like /dev/vgmain/lvroot (example name).
13. Now it’s time to run mkinitrd. rm the existing initrd in /boot and run mkinitrd with the -v switch. Make sure it pulls in lvm (and look for lvm.conf too).
14. Theoretically you’re now ready to go, and it’s time to reboot. (Last chance to touch /.autorelabel.) killall udevd; umount sys && umount proc && exit to get out of the chroot. umount the rest of the stuff for fun, maybe vgchange -a n and then mdadm --stop all your new RAID devices (since I’m paranoid and not sure if RHEL would do this for me, since they weren’t there at boot), and reboot.
15. Hopefully you can now select your new GRUB entry at boot, and boot from your new disks. (If you touched .autolabel you’re in for an extra reboot.) Once it boots, log in and make sure mount looks right, with your new LVM/RAID devices. Also check /proc/swaps to make sure the right swap device is being used.
16. Once you’re sure you’re OK, and you don’t want anything off the old disk, sfdisk --dump /dev/sdb | sed 's/sdb/sda/g' | sfdisk /dev/sda to copy the partition table from sdb to sda.
17. mdadm --manage --add the sda partitions to the RAID devices.
18. Wait for resync (i.e. bounce on cat /proc/mdstat).
19. Now go back to grub.conf, take out your extra entry (the one using (hd1,0)). Change the old entry (in my grub.conf I now only had one entry) to use the real root device path, so (ex.) root=/dev/vgmain/lvroot) instead of root=LABEL=/.
20. Make sure /etc/fstab looks right still. Again, I recommend against using LABEL= syntax for anything on software RAID or LVM.
21. I re-ran mkinitrd with -v, more than anything just to make sure it worked right. (Again: if your / is on LVM, make sure you see things like lvm.conf being put on the initrd. I didn’t the first time I did this, and it turned out to be because I was using LABEL=... syntax in /etc/fstab for /.)
22. Optional: I wrote a GRUB boot sector to sdb as if it were the first disk in the system. Run grub, device (hd0) /dev/sdb, root (hd0,1), setup(hd0). You can check that GRUB is now on sdb with something like dd if=/dev/sdb bs=512 count=1 | strings | grep GRUB and you should see GRUB as output.
23. Reboot (and pray, perhaps).

Once you’ve rebooted this last time you’ll probably want to look at mount to make sure everything is still where it should be, check your swap is on, and check /proc/mdstat to make sure the arrays are OK. In my case, and slightly to my surprise, everything was OK.

Sorry to the folks at The Planet if my turning off serial console stuff in GRUB/the kernel screws them up. (Feel free to drop me a line and I’ll turn it back on and update these instructions.)

day = {}
day["date"] = "date object here"
day["title"] = "string data here"
sections = day["sections"] = [dict(title="section title")]
jobs = sections[0]["jobs"] = []
jobs.append(dict(title="Google",
                 url="http://www.google.com"))
jobs.append(dict(title="Yahoo!",
                 url="http://www.yahoo.com"))

Perhaps pprint can make it easier to see what I’ve done here:

{'date': 'date object here',
 'sections': [{'jobs': [{'title': 'Google', 'url': 'http://www.google.com'},
                        {'title': 'Yahoo!', 'url': 'http://www.yahoo.com'}],
               'title': 'section title'}],
 'title': 'string data here'}

You might want to argue that I made bad choices WRT that syntax, since the pretty printed version above probably looks better. Here’s an alternative, I guess:

day = {"date": "calculate date object here",
       "sections": [{"title": "section title",
                     "jobs": [{"title": "Google",
                               "url": "http://www.google.com"},
                              {"title": "Yahoo!",
                               "url": "http://www.yahoo.com"},
                              ],
                      },
                     ],
       }
# Can't assign this in-line, unless I calculate "date" into a local
# variable first.
day["title"] = "this is based on " + day["date"]

It’s not really fair to say “just write it like pprint has.” pprint has a few advantages, such as having everything that it needs to put in its rendered data structure up front, and also being a computer. As a human writing this data structure, I think of the title before I think of putting in the jobs for example; pprint alphabetizes the keys, so it puts jobs first, which means you don’t potentially have }]}]} at the end of the structure. Also note that I needed one of the values in the structure to compute another; pprint already had that value when it went to render the data structure.

Also, I may need to think about switching from double quotes to single quotes. To my overly picky mind, they now look a little “cleaner.” My use of double quotes can be traced back to when I was frequently programming in C, but is not helped by the fact that '' and "" behave differently in languages such as Perl and the Bourne Shell. (C also makes/made me do slightly weird things in Perl and sh, such as writing 'x' and "xxx" with different quote types.)

So I went crazy and made a class which is currently called DataObject. It’s actually a somewhat disgusting set of wrappers over dictionaries, but check out the syntax:

day = DataObject()
day.date = "date object here"
day.title = "string data here"
day.sections[0].title = "section title"
day.sections[0].jobs.new_child(title="Google",
                               url="http://www.google.com")
day.sections[0].jobs.new_child(title="Yahoo!",
                               url="http://www.yahoo.com")

To me this is vastly more readable (and easier to write too), and it works just like the data structure I made above with Python’s built-in types. You can also ask for a clone of the data using built-in types by calling day.to_native() (it operates recursively).

I think there may be some weird side-effects, like weird exceptions that happen when you make a typo on a “key” (since attributes are mapped to keys) and a new object springs into existence. I’m going to try using it a bit more before I pass judgment on whether or not it’s a useful idea.

1. I can get on the web pretty fast from anywhere; especially fast with built-in 802.11b. EV-DO (rev. 0) isn’t anything to sneeze at, either.
2. Slide out QWERTY keyboard.
3. Pretty decent screen, including a flip to landscape when you slide out the keyboard.
4. Windows Live Search (and maybe Google Maps Mobile).
5. Microsoft Voice Command.
6. USB Mini-B connector built in. Good for charging, good for tethering.
7. USB and Bluetooth tethering is possible. (Supposedly. I enabled it as stated but I haven’t actually tried it yet.)
8. Windows Mobile (henceforth WM) is widespread enough that there’s a good bit of software available for it.

What I don’t like about the XV-6700:

1. No EV-DO rev. A. (The XV-6800 should be “soon” with rev. A however.)
2. Slow to turn on. Two seconds minimum to turn the device on. My Palm turns on almost instantly. My v710, which was a decent phone, was always on. My friend’s HTC TyTN on AT&T supposedly turns on within 0.5s (i.e. 4x faster).
3. Slow to use. Hit the start menu. Wait a bit. Wait for the browser to load. Wait for the phone to lock and turn the display off. Wait for the phone application to pop up. On a PC, I’m used to waiting. On a phone, I’m not, and I don’t really think I want to. All of this talking about slowness is based on my use of “dumbphones,” like my v710, and my Palm. My (several years old) Palm Tungsten C is practically instantaneous for launching any application.
4. The WM interface and I don’t really get along. Why does the “OK” button close applications? Moving around with the 4-way switch also screws me up sometimes; it seems inconsistent. (Granted, within Microsoft applications it’s probably pretty consistent. But this phone, from Verizon at least, seems to come with its share of third-party software already installed, not counting what else you’ll want to install (see below).) Also, why is it, when I think I’m closing an application, I’m not really closing it?
5. Lots of features that should probably be standard, but you end up having to pay extra for.
   • Microsoft Voice Command, which allows you to voice dial (built in to the v710, and really very usable): $40.
   • If I go to the bathroom and leave my phone on my desk, and I get a text message while I’m in the bathroom, WM doesn’t go out of its way to notify me that I have an unread message: you only get the notice when it comes in. Similar sorts of things may or may not happen with missed calls, e-mails, etc. (it’s not totally clear to me how all the notifications work). So you need Spb Phone Suite. $20. My v710 would beep or vibrate (depending on the mode you have it in) forever until you cleared it (with a hard button on the side while it’s still in the holster, even). You’ll also want Spb Phone Suite for the ease of changing ringer profiles from the Today screen. (You could change these on my v710 with hard buttons on the side, without flipping the phone open. If you’re minimally flexible, you can do it while it’s still in the holster.) (There may be a free application called something like “DontForget” that does this for you. Still, why isn’t this built in?)
   • Want applications to actually exit when you tap in the upper right? Want to easily switch between running applications? You need Spb Pocket Plus. $25. (There may be cheaper/free fixes for this too.)
   • Pocket IE (PIE) is supposedly deficient sometimes. Maybe you want Opera Mobile: $24. I don’t see much point in Opera, myself, except maybe that it works in a couple places where PIE doesn’t. (PIE seems pretty peppy to me.) What you really need, though, is Picsel Browser, a browser that’s actually useful for reading whole pages. I’d give you a price, but I don’t even think you can buy this; I think this is a browser made available to OEMs, like Samsung, to ship on their phones. (Note: Microsoft does have Deepfish in the pipeline, I guess. But you and I can’t use it right now, so who cares?)
   • You’re going to run out of hardware buttons, so you’re going to need (AE Button Plus)[http://ae.inc.ru/aebplusbuy.php], which I haven’t actually tried yet. $7.
6. I’ve soft reset the device several times. Powering on and off is sometimes a crap shoot: I press the power button, wait for a bit to see if it turns on. Oh, it didn’t, I hit it again. Whoops, maybe it was turning on slowly, because now it turned back off. My v710 was rebooting somewhat frequently before I got this phone, probably because I tended to be pretty rough with it (for example, I once tried to close a car door on it), but it still rebooted faster than this phone. I’ve had applications here and there seem to lock up too. (And did I mention the device is kind of slow?)
7. This may not be valid, but so far battery life seems kind of poor, compared to regular phone. I set it not to turn off automatically when on battery yesterday and I was in extreme low battery warning territory by the time I went to bed. If you set the phone not to turn off automatically, the good news is that the phone “turns on” [the backlight] rather rapidly; the bad news is that your battery won’t last. If you set it to turn off automatically, you have that painful delay to turn it back on.
8. Dialing on screen kind of sucks.
9. The speaker does not strike me as sounding very good at all, nor very loud. Turning it all the way up just makes sound go all to shit, whether using it as a speakerphone or for the OS sounds.
10. When using BT, the incoming voice is not very loud at all, and I can’t see to turn it up.
11. What is probably the last straw: when I lock the phone (by the way, sane locking—i.e., from a hardware button—seems to require third-party software) the “end call” button still ends the call. So I pop on my BT headset, start a call, lock the phone, stuff it into my holster, and I just hung up on the other person. I seem to do this with 100% accuracy. Yesterday I was on the phone with my dad. As I was getting out of the car, I said to him, “Yeah, I just got this new phone.” I then slid the phone into the holster and then we were disconnected. Perfect.
12. The screen is kind of small, and hard to browse with, frankly. (What are you going to do? It’s a phone, it still needs to be small enough to be practical. I don’t want to hold an 8” LCD up to the side of my head.)
13. No Bluetooth 2.0 EDR, so tethering with BT is supposedly pretty slow, especially relative to tethering with USB. (Again, I haven’t tried this.) In its defense, almost nothing has BT 2.0, and I think the only Verizon device that might have EDR is a Blackberry.
14. (Added) Sometimes the backlight goes to zero. For example, I’ll be trying to turn the phone on (see previous comments about how it doesn’t always seem to work, or work quickly at least) and somehow I’ll manage to turn the backlight off totally, and it won’t come back on until I find a decent light source where I can use the stylus to navigate to the backlight control panel and turn it up. (Why is there a backlight setting that has the backlight turn all the way off in the first place? Is that something people want, for the backlight to never be on?)

Now, there are two things to note about the way I’m trying to use this device that might lead some people to consider it “unfair”:

1. I don’t use Exchange. I’m not even sure I want e-mail on my phone; it’s not set up right now on this 6700. I hear that this phone’s Exchange integration is the bee’s knees, if you’re in to that kind of thing. So maybe I’m missing a big piece of what makes this phone so awesome for other people.
2. It’s a phone. At least, I think it’s supposed to be used as a phone. As a PDA, it might be alright. As a mobile browsing device (as long as you get your hands on some things like Live Search and Picsel Browser) it’s not bad. But I want a phone, and for that I think this device isn’t very good at all. (Seriously, why not lock the hard buttons! Totally unacceptable.) Part of this is due to physical considerations (i.e. hard button for numbers on the front) and some is software (no notifications of unread text messages). All the comparisons to my v710 are due to this fact: I wanted a phone that also has a good browser and fast Internet access, not a PDA that happens to occasionally make calls.

I don’t really want to convince people that love these HTC phones and Windows Mobile that their phone sucks. If you like it, and you can use it, that’s great for you. There are even more features this phone phone has that I didn’t mention and don’t take advantage of, perhaps; playing MP3s or gaming comes to mind.

For my tastes, though, I think the XV-6700 is going back in favor of a simple, fast, reliable, usable phone. Probably a Motorola, since I’m used to the interface (oh wait, Verizon fucked that up!), or maybe one of the LG models. (I probably need to stick with Verizon, at least for now.) For mobile browsing I think I’m going to be happier with something like an N800 running Linux kept in my bag, and maybe something insane like a FrogPad for more serious typing. Then I can tether it to… a dumbphone.