We! Haven't! Thought! This! Through!

So almost the entire world has exploded with news that Microsoft haven't bought Yahoo!, but are at least waving ridiculous amounts of TEH CAHS under the noses of the shareholders. But what would be the outcome of such a takeover? Microsoft and Yahoo! are in pretty much the same position, they both have technologically acceptable "online presence" services which are marketed really badly such that a competitor virtually owns the market. The only example of a service between them I can think of which is vaguely market-leading is Flickr, although Yahoo! Groups (which was eGroups) might still be popular, I expect that Facebook and Google groups are at least comparable, if not larger than it. Hotmail and Yahoo! Mail are both familiar names, but then online mail is now a free and worthless commodity, and everyone has been playing catchup with Gmail for the last couple of years. People don't "Windows Live Search" a thing, they "Google" it. People don't "Yahoo! Video" their dogs on skateboards, they "Youtube" them.

So the post-acquisition world would go from two implementations to one, but one that's still being marketed into the ground and with a few fewer workers. And all the transitional pain that Microsoft will impose on Yahoo! services, when someone remembers that FreeBSD isn't a Microsoft solution. M$ seem to be of the opinion that with a market they don't lead and $45Bn, the best approach is to lose the $45Bn and hire some other people who don't lead the market. Not, like, take that $45Bn and make their stuff better.

Permissions whee!

As in any good mystery, the question is who done it? MacNN reports a flaw in Tiger, Leopard in which an authenticated copy operation gives the destination files (the copies) the ownership of the logged-in user, not of the name they used to authenticate. The question is, which user did the copy?

Let's say there's a system with Alice Administrator and Richard Regular-User. Richard downloads a new application from the intarwebs, and wants to put it in /Applications (though why? Why can't he just put it in ~/Applications like a good little user? Never mind). The thing is, he doesn't have the right to do that. Finder presents him with an authentication dialogue, and no matter how many times he enters his username and password correctly, he can't acquire that right. However, he sees Alice walking past in the corridor and asks her to enter her admin credentials. For whatever reason, she agrees - now Alice has authenticated and Alice has acquired the right to copy the files. So even though Richard requested the copy, it was actually Alice who performed it. Therefore Alice created the files at the destination, so they should be owned by Alice.

The only thing which muddies the waters (and leads to the conflict of convenience vs. security which is described in that article) is that in many, or indeed most, cases on OS X where this will arise, Alice and Richard are actually the same person - Sammy the Single (Security-conscious, hence separating their use of the system into regular and admin accounts) User. It's a convenience that as Richard wanted the files copied, Richard now owns the copy - but this defeats the point of Richard existing, which is that Sammy doesn't want to be able to change /Applications without being warned.

Interestingly the same question doesn't get asked of the sudo command - it's clear that if I type sudo ditto Foobar.app /Applications/Foobar.app it's the super-user who does the work.

Side-by-side

A frequently-heard rider on the statement that Mac OS X "is more secure than Windows" is that fewer people are prodding its weak spots, because it has fewer users. Well, Windows Vista has a market share comparative to Mac OS X (all versions), and this report describes the security statistics as being somewhat comparable, too. So there we go.

How to solve every problem in Cocoa

Yes, really, every problem. Don't think of Cocoa as "simple things simple, complex things possible" (actually, was it Cocoapenextstepsody or Perl who started with that tagline? Or someone else? I digress) but "simple things simple, complex things simple but you're looking at it wrong". With Objective-C 2.0 (particularly properties), Core Data, Cocoa Bindings and Cocoa Scripting, almost every "it doesn't work" moment comes down to getting something wrong with KVC or with KVO - either observing the wrong key, or typoing a method name such that you aren't KVC-compliant for a key you need to be, getting validation wrong or unexpectedly going down the -setNilValueForKey: path. So do yourself a favour:

#define GLInstanceMethodEntryLog(format, ...) NSLog(@"-[%@(%p) %@] entry: %@", NSStringFromClass([self class]), self, NSStringFromSelector(_cmd), [NSString stringWithFormat: format, ##__VA_ARGS__])

Now because all of the retain count bugs disappeared when you turned the garbage collector on, the remaining issues are with that bit of code the PHBs are paying for ;-)

Project: Autonomous Revolutionary Goldfish

I was going to write, am still going to write, about how silly project names get bandied about in the software industry. But in researching this post (sorry blogosphere, I've let you down) I found that the Software-generated Gannt chart was patented by Fujitsu in the US in 1998, which to me just explains everything that is wrong with the way the US patent system is applied to software. For reference, Microsoft Project was written in 1987 (although is not strictly prior art for the patent. Project does everything in its power to prevent the user from creating a Gannt chart, in my experience).

Anyway, why is it that people care more about the fact that they're going to be using Leopard, Longhorn, Cairo, Barcelona or Niagara than about what any one of those is? As discussed in [1], naming software projects (though really I'm talking about projects in the general sense of collections of tasks in order to complete a particular goal) in the same way you might name your pet leads to an unhealthy psychological attachment to the project, causing it to develop its own (perceived) personality and vitality which can cause the project to continue long after it ought to have been killed. For every Cheetah, there's a Star Trek that didn't quite make it. And why should open source projects like Firefox or Ubuntu GNU/Linux need "code names" if their innards are supposed to be on public display?

I've decided that I know best, of course. My opinion is that, despite what people may say about project names being convenient shorthand to assist discussion, naming your project in an obtuse way splits us into the two groups which humanity adores: those of us who know, and those of you who don't. The circumstance I use to justify this is simple: if project names are mnemonics, why aren't the projects named in a mnemonic fashion? In what way does Rhapsody describe "port of OPENSTEP/Mach to PowerPC with the Platinum look and feel"? Such cultish behaviour of course leads directly to the point made in the citation; because we don't want to be the people in the know of something not worth knowing, we tend to keep our dubiously-named workflow in existence for far longer than could be dispassionately justified.

Of course, if I told you the name of the project I'm working on, you wouldn't have any idea what I'm working on ;-).

[1]Pulling the Plug: Software Project Management and the Problem of Project Escalation, Mark Keil. MIS Quarterly, Vol. 19, No. 4 (Dec., 1995), pp. 421-447

Objective-C Design Patterns

Certain events at work have turned me into a bit of a design patterns geek of late, and as such I stumbled across this DDJ article from 1997 (the title of this post is the link). According to del.icio.us not many other people have stumbled across it, but it's a great article. The code listing links seem to 404 even though the listings are at the bottom of page 1 of the article.

Something very important can be learned from this article, which is at best covered tangentially in the GoF book: Design patterns are not language-independent. Calling the C++ and Objective-C ways of writing code "pattern idioms" ignores the point that actually, the code you come up with is more important than the design (customers don't typically want to pay the same cash for your UML diagrams that they do for your executables), and gasp different languages require different code! Different patterns can be used in ObjC and Smalltalk than in C++, and different patterns again in object-oriented Perl. Different patterns will be appropriate for working with Foundation than with the NeXTSTEP (pre 4.0) foundation kit or with ICPak101. Designing your solution independent of the language and framework you're going to use will get you a solution, but will not necessarily produce the easiest solution to maintain, the most efficient solution or one that makes any sense to an expert in the realm of that language and framework.

FSF membership

I am now an associate member of the FSF. This is a good way to support Free Software development (including GNUstep, and you don't even need to be able to code :-). I've added a referral link to the sidebar - I don't get a kickback obviously, although I do get gifts if enough people are referred by me, and it helps the FSF to track where donors are getting their information from. If you use Free Software, you might consider donating some cash - especially now that the dollar's so crap ;-).

Post #100!

And to celebrate, we look at the differences between managers and humansprogrammers.

Upcoming Cocoa nerd stuff

I have organised a NSCoder Night for this coming Tuesday, November 27. It shall be in the Jericho Tavern pub at 8pm; bring yourself, bring an interest in Cocoa, and perhaps bring some code to talk about or work on. There won't be any agenda as such, just a group of NSCoders talking about NSCoding.

In January, PaulHR and I shall be entertaining OxMUG on the subject of Getting Things Done™ - in particular I have now started braindumping my many to-do lists into OmniFocus and I'm finding it very expressive and useful. In fact preparing that talk has just zoomed its way over to my OF inbox :-). That talk shall be Tuesday, January 8th.

Verify your backups

Apple shipped Mac OS X 10.5 this weekend, and three of the features are Time Machine, dtrace, and improved CHUD tools. Time Machine, dtrace, CHUD tools. iPod, mobile phone, web browser. Time Machine, dtrace, CHUD tools.

To spell that out in long hand, it's very easy now to see how various features in the Operating System behave. And in the case of Time Machine, we see that it walks through the source file system, copying the files to the destination. When I last gave a talk to OxMUG on the subject of data availability, it was interesting to notice how the people who had smugly put their hands up to indicate that they performed regular backups became crestfallen when I asked the second question: and how many of you have tested that backup in the last month?

Time Machine is no different in this regard. It makes copies of files, and that's all it does. It doesn't check that what it wrote at the other end matches what it saw in the first place, just like most other backup software doesn't. If the Carbon library reports that a file was successfully written to the destination, then it happily carries on to the next file. Just like any other backup software, you need to satisfy yourself that the backup Time Machine created is actually useful for some purpose.

+1-415-312-0555

Back in 1992, Robert X. Cringely wrote in Accidental Empires: How the boys of Silicon Valley make their billions, battle foreign competition, and still can't get a date [Oxford comma sic]:

Fifteen years from now, we [Americans] won't be able to function without some sort of machine with a microprocessor and memory inside. Though we probably won't call it a personal computer, that's what it will be.

Of course, by and large that's true; the American economy depends on microcomputers and the networks connecting them in a very intimate way. It's not obvious in 2007 just how predictable that was in 1992, as the "networks connecting them" had nothing like the ubiquity which is now the case. When "Accidental Empires" was written, the impact of a personal computer in an office was to remove the typewriter and the person trained to type, replacing both with someone who had other work to be doing typing on a system thousands of times more complicated than a typewriter.

What's most interesting though is the (carefully guarded; well done Bob) statement that "we probably won't call it a personal computer," as that part is only partially true. All of the people who have Tivos, or TVs, also have a personal computer. All of the people who have mobile phones and digital cameras also have a personal computer. The people who have Playstation 3s and Nintendo Wiis also have personal computers. In business, the people who annoy everyone else by playing with their palmtops in meetings instead of listening to what the amazingly insightful Cocoa programmer has to say are also wasting time trying to work out how to sync them with, yup, the personal computer they also have on their desk.

So the question to be asked is not why Cringely got it wrong, because he didn't, but why hasn't the PC already disappeared, to be completely replaced with the "it is a PC but we won't call it that" technology? Both already exist, both are pervasive, and the main modern use of both is remote publishing and retrieval of information, so why do we still tie ourselves to a particular desk where a heavy lump of metal and plastic, which can't do very much else, sits disseminating information like some kind of [note to self: avoid using the terms Oracle or Delphi here] groupthink prophet?

OmniWeb 5.6 tip of the day

defaults write com.omnigroup.OmniWeb5 WebKitOmitPDFSupport -bool TRUE

Sorry, but it doesn't view properly and doesn't print properly either :-(.

The times, they mainly stay the same

bbum displays a graph of the market capitalization (he's american, so the z sticks) of a few of the computer companies, noting that if after-hours trading isn't too surprising, then tomorrow (for Americans, again) the market will open with Apple being the biggest computer manufacturer on the planet. However, these figures fail to show something reasonably interesting.

What have IBM (up 24% y-o-y), HP (up 30 %) or Dell (up 21%) done to enamour you to their brand lately? If you're anything like me, then they've done nothing at all. Selling the same old Operating Systems on the same old hardware doesn't count as innovative. Compare them with Sun (up 13% year-on-year) or Apple (115%) and you'll see that there's basically no accounting for taste on the stock market. While Apple have been selling the shiny gadgets, Sun have been delivering the most observable operating environment on the planet and Dell have been doing, well, shit-all would be a polite phrase, and yet Dell have outstripped Sun in growing their stock price. In fact, HP have managed to blow up their stock price out of all proportion, while fighting scandals and the complete haemmorhaging of their management staff.

Nice-looking LaTeX Unicode

Because there was no other single location with all of this written:

\usepackage{ucs} % Unicode support
\usepackage[utf8x]{inputenc} % UCS' UTF-8 driver is better than the LaTeX kernel's
\usepackage[T1]{fontenc} % The default font encoding only contains Latin characters
\usepackage{ae,aecompl} % Almost European fonts/hyphenation do a better job than Computer Modern

There are a couple of characters I need (Latin letter yogh, Latin letter wynn + capitals) which aren't known by UCS, and I don't yet know how to add them. But this is a pretty good start.

Still trading as ClosedDarwin

It's not surprising, but while Apple's opensource page now includes a link to the iPhone software release (clicky the title), this only contains links to the WebCore and JavaScriptCore source, which is also available from the WebKit home on MacOSForge.org. While it is possible that the iPhone is distributed solely with software Apple can distribute without source, I wouldn't be surprised if there isn't just a teensy dollop of GPL code in there somewhere...

Old news

So the Inquirer thinks they've got a hot potato on their hands, with this "security flaw" in OS X. I've been using this approach for years (like, since NeXTSTEP): boot into single-user and launch NetInfo manually, then passwd root. Or in newer Mac OS X, nicl means you don't have to launch NetInfo.

Of course, if you give physical access to the computer without a Firmware password, then the 'attacker' may as well just boot from external media and do whatever they want from there. But the solution, as well as setting the Firmware password, is to edit the /etc/ttys file, change the line:

console "/System/Library/CoreServices/loginwindow.app/Contents/MacOS/loginwindow" vt100 on secure onoption="/usr/libexec/getty std.9600"

to:

console "/System/Library/CoreServices/loginwindow.app/Contents/MacOS/loginwindow" vt100 on onoption="/usr/libexec/getty std.9600"

Now the root password is required in single-user mode (as the console is no longer considered a secure terminal).

Holding a problem in your head

The linkied article (via Daring Fireball) describes the way that many programmers work - by loading the problem into their head - and techniques designed to manage and support working in such a way. Paul Graham makes the comparison with solving mathematics problems, which is something I can (and obviously have decided to) talk about due to the physics I studied and taught. Then I also have things to say about his specific recommendations.

In my (limited) experience, both the physicist in me and the programmer in me like to have a scratch model of the problem available to refer to. Constructing such a model in both cases acts as the aide memoire to bootstrap the prolem domain into my head, and as such should be as quick, and as nasty, as possible. Agile Design has a concept known as "just barely good enough", and it definitely applies at this stage. With this model in place I now have a structured layout in my head, which will aid the implementation, but I also have it scrawled out somewhere that I can refer to if in working on one component (writing one class, or solving one integral) I forget a detail about another.

Eventually it might be necessary to have a 'posh' layout of the domain model, but this is not yet the time. In maths as in computing, the solution to the problem actually contains the structure you came up with, so if someone wants to see just the structure (of which more in a later paragraph) it can be extracted easily. The above statement codifies why in both cases I (and most of the people I've worked with, in each field) prefer to use a whiteboard than a software tool for this bootstrap phase. It's impossible - repeat, impossible - to braindump as quickly onto a keyboard, mouse or even one of those funky tablet stylus things as it is with an instantly-erasable pen on a whiteboard. Actually, in the maths or physics realm, there's nothing really suitable anyway. Tools like Maple or Mathematica are designed to let you get the solution to a problem, and really only fit into the workflow once you've already defined the problem - there's no adequate way to have large chunks of "magic happens here, to be decided at a later date". In the software world, CASE tools cause you to spend so long thinking about use-cases, CRC definitions or whatever that you actually have to delve into nitty-gritty details while doing the design; great for software architects, bad for the problem bootstrap process. Even something like Omnigraffle can be overkill. it's very quick but I generally only switch to it if I think my boardwriting has become illegible. To give an example, I once 'designed' a tool I needed at Oxford Uni with boxes-and-clouds-and-lines on my whiteboard, then took a photo of the whiteboard which I set as the desktop image on my computer. If I got lost, then I was only one keystroke away from hiding Xcode and being able to see my scrawls. The tool in question was a WebObjects app, but I didn't even open EOModeler until after I'd taken the photo.

---

Incidentally, I expect that the widespread use of this technique contributes to "mythical man-month" problems in larger software projects. A single person can get to work really quickly with a mental bootstrap, but then any bad decisions made in planning the approach to the solution are unlikely to be adequately questioned during implementation. A small team is good because with even one other person present, I discuss things; even if the other person isn't giving feedback (because I'm too busy mouthing off, often) I find myself thinking "just why am I trying to justify this heap of crap?" and choosing another approach. Add a few more people, and actually the domain model does need to be well-designed (although hopefully they're then all given different tasks to work on, and those sub-problems can be mentally bootstrapped). This is where I disagree with Paul - in recommendation 6, he says that the smaller the team the better, and that a team of one is best. I think a team of one is less likely to have internal conflicts of the constructive kind, or even think past the first solution they get concensus on (which is of course the first solution any member thinks of). I believe that two is the workable minimum team size, and that larger teams should really be working as permutations (not combinations) of teams of two.

Paul's suggestion number 4 to rewrite often is almost directly from the gospel according to XP, except that in the XP world the recommendation is to identify things which can be refactored as early as possible, and then refactor them. Rewriting for the hell of it is not good from the pointy-haired perspective because it means time spent with no observable value - unless the rewrite is because the original was buggy, and the rewritten version is somehow better. It's bad for the coder because it takes focus away from solving the problem and onto trying to mentally map the entire project (or at least, all of it which depends on the rewritten code); once there's already implementation in place it's much harder to mentally bootstrap the problem, because the subconscious automatically pulls in all those things about APIs and design patterns that I was thinking about while writing the inital solution. It's also harder to separate the solution from the problem, once there already exists the solution.

The final sentence of the above paragraph leads nicely into discussion of suggestion 5, writing re-readable code. I'm a big fan of comment documentation like headerdoc or doxygen because not only does it impose readability on the code (albeit out-of-band readability), but also because if the problem-in-head approach works as well as I think, then it's going to be necessary to work backwards from the solution to the pointy-haired bits in the middle required by external observers, like the class relationship diagrams and the interface specifications. That's actually true in the maths/physics sphere too - very often in an exam I would go from the problem to the solution, then go back and show my working.

Template change

I had to make some minor edits to the Blogger template used here anyway, so I decided to have a little monkey with the fonts. Here's what you used to get:

And here's what you now get:

I think that's much better. Good old Helvetica! I don't understand anything about typography at all, but I think that the latter doesn't look as messy, perhaps because of the spacing being tighter. Interestingly the title actually takes up more space, because the bold font is heavier. Marvellous.

Random collection of amazing stuff

The most cool thing that I noticed today ever is that Google Maps now allows you to add custom waypoints by dragging-and-dropping the route line onto a given road. This is great! I'm going to a charity biker raffle thing in Pensford next weekend, and Google's usual recommendation is that I stay on the M4 to Bristol, and drive through Bristol towards Shepton Mallet. This is, frankly, ludicrous. It's much more sensible to go through Bath and attack the A37 from the South, and now I can let Google know that.

Trusted JDS is über-cool. Not so much the actual functionality, which is somewhere between being pointy-haired enterprisey nonsense and NSA-derived "we require this feature, we can't tell you why, or what it is, or how it should work, but implement it because I'm authorised to shoot you and move in with your wife" fun. But implementing Mandatory Access Control in a GUI, and having it work, and make sense, is one hell of an achievement. Seven hells, in the case of Trusted Openlook, of which none are achievement. My favourite part of TJDS is that the access controls are checked by pasteboard actions, so trying to paste Top Secret text into an Unrestricted e-mail becomes a no-no.

There does exist Mac MAC (sorry, I've also written "do DO" this week) support, in the form of SEDarwin, but (as with SELinux) most of the time spent in designing policies for SEDarwin actually boils down to opening up enough permissions to stop from breaking stuff - and that stuff mainly breaks because the applications (or even the libraries on which those applications are based) don't expect to not be allowed to, for instance, talk to the pasteboard server. In fact, I'm going to save this post as a draft, then kill pbs and see what happens.

Hmmm... that isn't what I expected. I can actually still copy and paste text (probably uses a different pasteboard mechanism). pbs is a zombie, though. Killed an app by trying to copy an image out of it, too, and both of these symptoms would seem to fit with my assumption above; Cocoa just doesn't know what to do if the pasteboard server isn't available. If you started restricting access to it (and probably the DO name servers and distributed notification centres too) then you'd be in a right mess.

It's update o'clock

In other words, it's "Graham remembers that someone needs to write the interwebs, too" time. The main reason I haven't written in a while is that I'm enjoying the new job, so it's satiating my hacking desires. No hacking projects = nothing to talk about. I can't really talk about the work stuff, either; this is unfortunate because I did some really cool KVC-cheating in a prototype app I wrote, and it'd be a good article to describe that.

I've more or less dropped off the GNUstep radar recently. I still need to talk to the employers' legal eagles in order to update my FSF copyright assignment, and then find something to hack on. Currently I only have a Mac OS X machine so I'd probably switch to some app-level stuff. I have half a plan in my mind for a SOPE app, but despite reading all the documentation I still haven't worked out how to get started :-|. The code isn't too much of a problem, I've used WebObejcts before, but WebObjects has a 'hit this button to build and run your WebObjects code' button, and there's no description AFAICT for SOPE of what to put in the GNUmakefile to get built and running SOPE code, even whether you're supposed to provide your own main() or anything. Hmmm...I wonder if there's a sample project around...