Ubuntu on Intel iMac Review

 Computing  2 Responses »
Feb 262009
 

Yes I know everyone and their dog has already written a review of the Intel iMac, but I have not done so yet. This is a review of the 24″ iMac (and I’m already hating that incorrect capitalisation) with the specific intent of putting Ubuntu on. This is not some kind of weird anti-OSX statement; I already have a laptop with OSX installed on it and it does seem like a fun operating system.

But this is a replacement for my main desktop, and I really want a “proper” Unix on it, and Linux will do in the meantime.

First Thoughts

First of all, the screen stand should allow adjustment in the vertical direction; already I can see myself getting out an extremely old and manky tape drive to sit underneath to raise the screen to an appropriate height. Apple ? Your lack of foresight in not including height adjustment is ruining the look of the system!

Nice keyboard! If you do not type much. I am aware that some people really like the skinny Apple keyboards, but it is not for me even though they got off to a good start by not including Windows keys. Back to the Das Keyboard for me I think. The mouse is similar – there’s this nice funky ball on top which is an improvement over the usual scroll wheel (although I am not too sure how well it would work at speed), but just not enough buttons.  Or at least it does not feel like enough buttons. The “one button” with two effects method as appears to be the case here is a little odd and off-putting.

Perhaps Apple needs a special country kit – “Special Clicky Keyboard And Mouse With Too Many Buttons For The Unix Geeks”. How many people end up using a non-Apple keyboard and mouse ? Perhaps not many, but why not cater to them with alternative keyboards and mice ? My Apple keyboard and mouse will be mostly unused.

Where are the memory card slots though ?  It would make things a bit more complete (and the iMac is about one box doing everything) if there were a sensible selection of memory card slots.

In terms of software (and not OSX itself), one thing becomes immediately apparent when booting (and on previous occasions when trying to boot from CD, diagnosing booting problems, etc.). The Apple firmware breaks the first rule of user interface design! Not something you expect Apple to do.

The firmware needs to be just a little bit more expressive about what is going on. You may well be thinking that as a hardcore Unix geek I want to see inscrutable messages from the firmware about initialising that chipset, addresses of where adapter cards are, cpu values, etc. And of course you are right.

But basic messages about starting the hardware would still be helpful.

More importantly however, the Apple firmware should be letting you know what keystrokes are needed to do “unusual” things like boot from a CD, an external hard disk, start the hardware diagnostics, etc. One of the most irritating things about Apple hardware is the need to provide secret incantations to boot from CD  – you hold the “C” key down for “a while” (how long anyway?).

The Install

At this point the “unusual” choices of Apple bite you when it comes to installing a version of Linux intended for use on mainstream PCs. First you have to install rEFIt, then you install Linux off CD (and mess around with the MBR partition table), then have to remember to “resync” the partition tables.

Seems there’s an EFI partition table and an MBR partition table that need keeping in sync. Having two partition tables immediately strikes me as a dumb idea. When Windows is involved, there is probably no fix for this problem, but why is Linux still not doing things properly ? Or at least not doing the sensible thing by default.

It also means there is effectively a two step boot process – first rEFIt starts, then then starts grub which finally starts Linux; this is not a quick system to boot.

Fixing The Niggles

In any install, there are always little niggles that need fixing. The most obvious is a way to control the brightness of the screen which by default is far too bright. There may well be better solutions out there, but a bit of C coming from http://www.felipe-alfaro.org/blog/2006/09/11/basic-backlight-support-for-macbook-pro

A quick compile and install in /opt/bin/bl and root can set the backlight brightness with :-

bl (1-15)

Adding this in an appropriate way to /etc/rc.local ensures that the backlight is set on every boot.

It also appears that we need to do a bit of hacking to support the sound properly. Adding an option to /etc/modprobe.d/options specifies the “model” of soundcard we are using to get sound working :-

options snd-hda-intel model=imac24

A quick reboot and sound is working (microphone not tested!).

For some reason the module that is used to gain access to the iMac temperature probes is not loaded automatically. Adding applesmc to the end of /etc/modules gets this loaded (after a reboot or manually with modprobe applesmc). Unfortunately there does not appear to be an immediately obvious way of using this except from the command line.

The wireless network controller apparently works after the addition of the proprietary driver that shows up after doing an update. Admittedly I cannot say for sure because I use a wired setup.

Lastly the IR receiver. I will admit this has currently defeated me although that is partially because I am not that interested. I will of course update this if I get it to work.

Later: Screen Calibration

I later took a look at setting up the screen properly. Proper controls for the screen would have been nice, but configuring from the system turns out to be relatively easy.

First of all I used the OSX screen calibration tool in “expert” mode to generate in ICC file containing the screen profile. Doing this may well be possible inside Ubuntu; I just happened to know where the tool was in OSX.

I then installed xcalib :-

apt-get install xcalib

This could be used to set the monitor profile from the earlier generated ICC file.

Conclusion

It works. After a week or so using it, I am no longer thinking of the iMac as a system being installed and tested but as my standard desktop.

Solaris – Always Mount All ZFS Filesystems In Single User Mode

 Computing  2 Responses »
Feb 252009
 

Traditionally I have always mounted just the filesystems I needed in single user mode whilst tinkering in Solaris. Turns out this is a dumb method for ZFS filesystems.

What happens is that the zfs mount command will create any directories necessary to mount the filesystem. Later this can stop other ZFS filesystems from mounting when the tinkering is finished. This could be an argument for not creating hierarchies of filesystems, but that’s rather extreme.

The better solution is to mount all the ZFS filesystems in one go with :-

zfs mount -a

Support for the Royal Mail

 General  No Responses »
Feb 242009
 

Seeing as there is currently a fuss about the possible partial privitisation of the Royal Mail, it is good time to add a little support for the Royal Mail as it is. The introduction of private sector “expertese” may not improve the service for customers – indeed may make things worse. Of course those who champion the private sector claim that it will improve the service which I do not believe will be the case at all.

Speaking in particular on parcels (as I have little interest in letters as most of them seem to be bills or junk mail), the Royal Mail delivers a service that is far better than private sector delivery companies (excluding supermarkets who seem to be able to organise deliveries far better than those whose business is making deliveries). As a single person, I am often during the working week to be found at work!

If you order something from the Internet, you can sometimes ask for it to be delivered to your work address – if you have a co-opertive workplace (and workplace that doesn’t like workers having parcels delivered to work is to put it mildly completely bonkers). But not always.

And of course if you have something delivered to your home address, it will normally be delivered when you are out. I happen to be home at lunchtime which gives an extra window of opportunity for the delivery people to catch me in. And what “company” manages that more than any other ? Yes, the Royal Mail.

As it happens I have one of those little notices saying that some company tried to make a delivery and I was not in. I can ask for it to be redelivered to the same address (when I will almost certainly also be out unless I take an extra day off work), or I can pick it up from the depot. Where are all these depots ? Well they all seem to be in industrial estates miles from anywhere and almost always very difficult to get to with public transport (I don’t drive).

Except of course for the Royal Mail who alternate between my local post office (which is less than 100 metres from my flat) or the local “big” post office, which is somewhat further but far easier to get to than some out of town industrial estate.

If I had the choice when ordering things from the Internet, I would always opt for a Royal Mail delivery even if it were 25% more expensive. But as soon as private sector “expertese” gets to work, I dare say the Royal Mail will start behaving like other delivery companies and having cheap out of town collection depots.

Apple – Deceptive Delivery Claims?

 General  No Responses »
Feb 142009
 

So you buy something cool from Apple (in my case a 24″ iMac) and you’re promised that it’ll turn up in three business days.

Or maybe not?

First of all when you open the Apple online store, if you’re looking at the UK store it will say an iMac will ship in under 24-hours. Interestingly enough those in the US get a lower quality of service as their store says it ships in 1-3 days. But make any change to your iMac at all, and the delivery time shoots up to three days (to be precise the phrase is “Ships: 3 days”).

So you order your iMac and all of a sudden the expected delivery date lurches further off in time. In my case I ordered my iMac on the 11th Feb expecting it to turn up early in the next week. The first estimate of when it would turn up was the 18th (Wed) and is now the 19th (Thu); neither of which I would classify as “early in the next week” or anywhere near the 3 days specified.

Apple will quite probably (and almost certainly correctly) claim that the fine print in their ordering process clearly states that three days for adding an extra RAM DIMM, and three further days for delivery is perfectly reasonable, and that the optimistic delivery dates are what happens in the most favourable possible circumstances. And I am not claiming Apple is unique in this sort of behaviour.

But this sort of deceptive shit is what gives salescritters such an evil reputation; enough that some of us believe they could possibly be some sort of special category of subhuman. If you are not sure that you can deliver something the next business day, do not say you can even if it sounds good. You may have a “get out of jail free” card in your fineprint, but that does not stop you looking like a scumbag.

Ideally do not say anything about delivery time until you have all the information – so you know that I have ordered that funky cable that takes an extra day to get packaged. And then give a delivery estimate, and emphasise that it is an estimate.

If someone is curious enough to find out how long it will take for the iMac to be delivered before they start the ordering process they can probably be counted on to hit a button titled “Delivery Times” where you can explain in full how long it takes to deliver an iMac including all the variations.

It is sort of old-fashioned to expect anyone to keep their word without paying attention to whether they are legally obliged to, but it does give a good impression. And all it takes is to avoid promising things you cannot deliver – surely it is worth that to give a good impression!

Revisiting Unix Basics: The df Command

 Computing  No Responses »
Feb 082009
 

I was reading a comment about the df command (in relation to reserved filesystem space) and realised that the clueless newbie was right; it is odd that df does not mention reserved space. Of course it would also be wrong for df to lie about the matter too. I then realised that df is long overdue for a bit of refreshing. If you look at the typical output of the df command, you will find it inconveniently cluttered :-

Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/datavg-810root
                       12G  7.8G  4.3G  65% /
tmpfs                 2.0G     0  2.0G   0% /lib/init/rw
varrun                2.0G  416K  2.0G   1% /var/run
varlock               2.0G     0  2.0G   0% /var/lock
udev                  2.0G  3.1M  2.0G   1% /dev
tmpfs                 2.0G  344K  2.0G   1% /dev/shm
lrm                   2.0G  2.4M  2.0G   1% /lib/modules/2.6.27-7-generic/volatile
/dev/sdb1             130M   36M   88M  29% /boot
/dev/mapper/datavg-opt
                      2.0G  776M  1.3G  39% /opt
/dev/mapper/datavg-810var
                      5.0G  1.4G  3.7G  28% /var
/dev/mapper/datavg-home
                      256G  116G  141G  46% /home
/dev/mapper/datavg-vmachines
                       96G   62G   35G  64% /vmachines
/dev/mapper/datavg-bragspool
                      256G  6.2G  250G   3% /var/spool/brag
/dev/mapper/datavg-herpesbackup
                       16G  4.6G   12G  29% /var/herpes
/dev/sda1             463G  147G  293G  34% /mdata
/dev/scd0             2.4G  2.4G     0 100% /media/CIVCOMPLETEEU
/dev/mapper/datavg-cdimages
                       32G  1.9G   31G   6% /cdimages
/dev/mapper/datavg-ontapsim
                       16G  498M   16G   4% /sim

Part of the problem is that df does not do quite what it claims to do … to report free space on the mounted filesystems. It also gives some (a very small amount) of additional information about the relevant filesystems … particularly the device the filesystem is mounted on. This “helps” to make the output more cluttered that it needs to be. It is possible that there are those who will argue that the device is the filesystem and not where it is mounted; they are arguably right, but when you use df you are either looking at where in the Unix file hierarchy there are places that have less space than is comfortable, or for places that have enough space to put that big file you are about to download.

Next the command itself has an obscure command to make it easier to type on a slow type-writter like terminal (those who are below a certain age will not realise that we used to comminicate with Unix machines using a terminal that was more like a printer than the screens we use today). It might be better named fsspace with an alias of diskspace for those who want to concentrate on what worries them rather than on what worries the machine.

Next why not take advantage of certain features that have crept almost silently into the command line over the last few decades ? Why not adjust the output to the width of the terminal window (look for the $COLUMNS evironment variable), spacing things out or even adding more information when you have enough space?

Finally if you were to dig around the df command a little bit you will encounter something peculiar called “inodes”. Now I know what an inode is, and I dare say quite a few people reading this will know, but if you do not, knowing how many inodes there are is not very useful information. It is relatively rare (these days) for a filesystem to run out of inodes so this information has a low priority, and why not use a term more understandable than “inodes” ?

Changing a term is something to be avoided in most circumstances which is why we still have “inode” where even the originator of the term has to guess that the “i” means “index”. I would suggest that something like “fileslots”or perhaps “fslots”

We now have the basic specification of something that should look like :-

% diskspace
Filesystem                            Size  %Used %fslots  Avail
/                                      12G    70%      3%   3.6G
/lib/init/rw                          2.0G     0%      0%   2.0G
/var/run                              2.0G     0%      0%   2.0G
/var/lock                             2.0G     0%      0%   2.0G
/dev                                  2.0G     0%      1%   2.0G
/dev/shm                              2.0G     0%      0%   2.0G
/lib/modules/2.6.27-7-generic/vola+   2.0G     0%      0%   2.0G
/boot                                 130M    29%      0%    88M
/opt                                  2.0G    40%      1%   1.2G
/var                                  5.0G    18%      0%   4.1G
/home                                 256G    52%      0%   124G
/cdimages                              32G    65%      0%    12G
/mdata                                463G    36%      1%   280G

This could be improved in some ways – for instance it would be helpful to skip over certain of the filesystems that are not strictly speaking backed by disk. However it is beginning to be useful.

Or would be if the code exists. Fortunately it does.

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