I recently reinstalled the OS on one of my Macs, and I’ve got backup scripts on my CentOS Linux box that use rsync to back up some pertinent data, so I had to reestablish the SSH key between the machines and had a hard time remembering how to do it. So this time I’m documenting what I had to re-learn.

First of all, there’s a great post over at nixCraft that basically explains how to do it. But allow me to explain more thoroughly, ahem, dumbed down to my level. 

The key is remembering which machine is filling which role when you’re reading the instructions. I’ll call them the “Acting” machine–the one who is taking action and performing a command, let’s say an rsync command–and the “Target” machine–the one who is being acted upon. In my case, the Linux server is the acting machine performing the rsync command, and my Mac is the target.

The process is simple. On the “Target” machine, generate a key, and then give that key to the “Acting” machine, which effectively gives it “permission” to login without the need to supply username/password credentials.

So, from the “Target” machine, in this case, my Mac, type the following command:

ssh-keygen -t rsa

This will generate a couple files that serve as a key for accessing the Mac. The ssh-keygen command may ask you where to store the key and what password to use. Just hit enter to use the default path and a blank password.

Next, still from the “Target” machine (my Mac), type:

ssh MyUsername@ActingServer ”mkdir .ssh”
scp .ssh/id_rsa.pub MyUsername@ActingServer:.ssh/authorized_keys2

In the code above, MyUsername@ActingServer would be the username and address (for instance, perhaps the IP address) of the “Acting” machine, in my case, the Linux server. In the first line, you’re just creating the .ssh directory if it doesn’t exist. In the second line, you’re copying the key you generated from the “Target” machine to the “Acting” machine, or from the Mac to the Linux server.  Note that the scp command will ask for the password to the MyUsername account because it is connecting to that server to send it the key.

Voile. As if by magic, the “Acting” machine should now be able to SSH into the “Target” machine without a password prompt. Correspondingly, you should be able to perform rsync and other SSH commands without a password prompt. Please note, however, that this is only a one-way key. We only gave my Linux server permission to access my Mac.

What if I want my Mac to similarly login to the server without a password prompt? In that case, the Mac and the server have effectively switched roles; the Mac is now the “Acting” machine and the server is the “Target” machine, so we just have to repeat the process from the other direction. Generate a key from the server and send it to the Mac. At that point, both machines will be able to access each other without a password prompt. 

What if I have multiple “Targets” that the “Acting” machine will connect to? For instance, perhaps I have multiple Macs, and the Linux server is running scripts on all of them. When you’re sending the key to the “Acting” server with the scp command, use a different name for each key file, don’t overwrite the same file each time! So in the example code above, we’re sending the key as “authorized_keys2″. When repeating this process for multiple targets, send the keys as “authorized_keys3″, and so forth.

Hopefully this will clear up some confusion regarding this process.

You can view the MacRumors WWDC 2008 Spoiler Free news page if you want to do the same.

Many developers were frustrated–and many web developers had our curiosities pleasantly piqued–when Apple initially announced that “software” would be available for the iPhone in the form of Ajax web applications. Naturally, many of the disappointed folks were irritated because the web platform is something that they’re entirely unfamiliar with, probably having backgrounds in Objective C or something similar; probably a minority were disappointed because their target application legitimately could not be powered by HTML and Ajax.

That said, it is indeed a very thought-provoking concept: Using web technology as your application environment. As most web developers will attest to, there honestly isn’t that much that a typical application does that cannot be accomplished with web technology. With the advent of Ajax frameworks, applications built with web technology can have very similar responsiveness and dynamics of a “classic” application. Especially when you remove the burden of cross-browser compatibility, in the iPhone’s case.

But with the iPhone/iPod Touch scenario, it is irritating that the application has to reside in Safari and has to be loaded off the web. It almost feels as if Apple was trying to push something that wasn’t…quite…ready. Something like AIR!

AIR accomplishes everything that Apple was suggesting for the iPhone environment, but for the desktop. Use web technology, but write a “compiled”, stand-alone application that really doesn’t even have to use the web. Use HTML. Use Ajax. Use Flex and Flash. Have a nice encapsulated application on your desktop. Especially when you throw the Flash technology into the platform, it is now a very capable environment for a large variety of applications, without being constrained to the browser. Wouldn’t it be great if that same cross-platform environment, AIR, worked on the iPhone as well?

Oops, Flash technology isn’t currently supported by the iPhone. That is actually another source of contention. And the AIR environment does lose some of its punch without Flash and Flex, even though its HTML/Ajax implementation can do a very decent job with most typical applications.

Steve Jobs has made it clear that he likes the idea of web technology powering iPhone apps. Now, consider some of the facts. Apple announces the iPhone SDK will be released in February, and then fails to deliver. Meanwhile, Flash still isn’t found on the iPhone, and Adobe “invents the wheel” by getting web technology to drive native apps through its work with AIR. Is there a common theme with these events? Perhaps something like: Are Apple and Adobe working together to get the much-needed Flash technology onto the iPhone and, subsequently, releasing an SDK that uses AIR technology, with hooks into the iPhone system just like AIR currently has hooks into the Linux, Windows, and Mac OS X desktop operating systems?

It wouldn’t be the first time Apple has had to wait for its partners, or take the heat for them. For instance, Apple has clearly been taking a lot of heat for many factors of the iPhone that are clearly not in Apple’s interest, but in AT&T’s.

And this scenario would fit the circumstances around Adobe’s development of AIR. Adobe has been working on AIR since well before the iPhone was released, but AIR wasn’t officially released until February 25, 2008. Even if Apple and Adobe were working closely together, there just hasn’t been enough time for AIR to get released and hooks to be developed to provide iPhone-specific functionality in AIR. Adobe has understandably concerned itself with its own business first. With that done, attention can turn to Apple to support them in concluding their own business.

Of course, this prediction is a reflection of my own desires as much as it fits the circumstances. As a developer that uses Adobe technology including Flex and AIR, and an Apple enthusiast for more than 20 years, I would love to see things happen this way. Undoubtedly we will have a clearer idea of Apple’s iPhone development roadmap after this Thursday.

As if the thought of an “iPhone AIR” isn’t confusing enough.

I opened up the Activity Monitor in the Utilities folder, set it to view “All Processes”, and noticed that a process named “PrintJobMgr” was using a lot of processor time and took up over 600MB.

As it turns out, this has been discussed on Apple’s forums. It seems to be happening to people when there is a print job that never was printed, and thus is continually waiting in the print queue. I’m not sure how, but this is exactly what happened on my iMac, and deleting the print job in the queue fixed the problem.

I’m hoping Apple fixes that one soon.

It worked great. Instructions were very clear and the process was mildly simple.

My OCD felt much better having a nice, clean, system. After reinstalling the iLife apps from my System Restore discs, there were some updates available, so I started the system update process. Halfway through, my system took a hard freeze and I couldn’t do anything. I even connected via SSH from another machine and tried to kill potential suspects that might have been causing the freeze. Nothing. I tried to reboot from the command line. Nothing.

With no other recourse, I did the unthinkable: I held down the power button. Not a terribly big deal, right?

Upon rebooting, I was welcomed with the registration window that appears the first time you boot up a new Mac. “Weird, but that’s fine,” I thought. I filled it out. Upon finishing, the window disappeared and reappeared, asking me to fill it out all over again. And again. And again.

I’m completely locked out of my computer because I can’t get past that registration window, and don’t know what to do without reinstalling the OS again.

Here’s one cranky Leopard user. At least, I wish I could use it.

UPDATE: This issue is confirmed on Apple’s support page. I discovered this from Ars Technica’s Infinite Loop blog (ironic, isn’t it?) in the iMac 1.2.1 Update article.

Spaz gets more time in the Twitter limelight, and Ed talked up the benefits of AIR. Good job, Ed! I haven’t had a chance to read the whole interview yet, but look forward to reading it soon.

It autopopulates the return address by looking up your “Me” record in the OS X address book. You may then fill in the destination address by searching for a contact or by manually typing in an address. Very well thought out.

The widget did a great job at getting over typical problem areas, like printer and paper size. Overall, this widget is definitely Ambrosia calibre. And it’s free!

iStat Pro is cooler than any of the tools they have. Developed as a dashboard widget, iStat Pro displays CPU temperature and fan speed, but also duplicates all the information in Activity Monitor, displaying typical geek Unix system info, like active processes, memory usage, and so on.

All in a dashboard widget, and all for free (donationware)!

Nevertheless, in her review entitled Uninspiring Vista, Erika Jonietz explains how Windows Vista, as nifty as it is in many ways, was the straw that broke the camel’s back and caused her to appreciate how awesome OS X is and the entire Macintosh experience can be.

A great read for any Mac fan!

Unfortunately, some of us humans might try so hard to leverage our computer’s multitasking abilities that the ultimate bottleneck becomes the limit of our own mental concentration. You’re working on a document, but you also have your email client open and perhaps a few tabs on your web browser. Before you know it, you’ve wasted a significant period of time replying to email or going off on a tangent through the web, when the most important task at hand was just to finish typing up that document.

Enter WriteRoom. It may seem archaic by today’s standards to boot up your computer into a word processor program and to only be able to use your computer for that purpose until you finish and boot into another program, but it sure didn’t test human self-control and concentration like the systems we have today. WriteRoom duplicates that simple, distraction-free experience, and while you’re at it, gives you a bit of nostalgic joy in the process. Sure, you could get a similar affect by opening TextEdit (on the Mac) or Notepad (on Windows), but where’s the joy in that experience?

Did you grow up on an Apple ][ using AppleWorks with a green-on-black monochrome monitor? WriteRoom’s default scheme duplicates just that environment. Did you have the DOS PC’s common white-on-blue? Or can you just not stand anything but black-on-white? Fine, the color scheme is customizable. So is the font, so you don’t have to stick with a monospaced font, although it sure adds to the nostalgia.

And the best part is that you don’t have to give up the multitasking bit to use WriteRoom. You can run iTunes and download that huge file in the background, but experience a visually simple and uncluttered experience while working on your text document.

WriteRoom is for the Mac only, and the original version is free. A clone called Dark Room was written to respectfully “capture the essence of WriteRoom” for Windows machines, and is also free.

Even though I think it is pretty blatant, for those of you who do not realize: David is using a common linguistic tool known as sarcasm.

These newest screenshots feature some of the new features that have been reported, such as (a) Improved firewall, (b) More convenient Spotlight features, (c) Lost file recovery, and (d) Improved UI, which (no surprise here) matches the new UI in iTunes 7. Included in this is resolution independence of UI elements. Apple is pushing the envelope, as always.

Summing it up as a glorified backup app is an obscene oversimplification. As a developer, I immediately recognized in Time Machine the likelihood that it is running on top of a revision control system, and that is what really fascinates me about it, and incidentally that is also what I feel many people misunderstand about it, leading them to discount it. I’m not alone in making this connection; really, any developer who uses and understands source code repositories probably had the thought cross his or her mind. One of the major advantages mentioned in discussions about revision control is the fact that you can always retrieve your file as it existed at any point in the past when it was committed to the repository.

And it’s not a stretch to see Apple borrowing revision control software to implement Time Machine. Subversion is a very popular revision control project in the opensource community. Sitting on top of FreeBSD, Apple has incorporated many other opensource projects in Mac OS X. For instance, OpenGL, Apache, SSH, FTP, CUPS, and Samba come to mind, just to name a few. Why not add Subversion to the list of excellent technologies to incorporate into an excellent OS?

If Time Machine is running on top of Subversion or a similar revision control system, that would address the concerns that some people have–people who might not understand how revision control systems work. Some people have expressed a concern that a backup drive would not be able to support Time Machine for very long before filling up. For instance, if you have a 1GB file (perhaps a video clip) and make a very small change to it, will Time Machine record that change by making another copy of the entire file? If Time Machine made its backups as full copies of the changed files, you can imagine how quickly a backup volume would fill up. But that simply isn’t how most revision control software works. Most revision control software, including Subversion, uses Delta Compression to calculate only the changes made to a file, and then saves only those changes. Thus, a file can be committed to a repository a dozen times, and yet the amount of drive space taken up would only amount to the changes made, plus perhaps a very slight amount of overhead in the repository for tracking each change.

So that covers feasibility. With some software like Subversion, Time Machine could provide a backup of your entire volume and actually support it for a decent period of time thanks to efficient delta compression. What about the logistics of finding the changed files and saving those changes? This would be simple even with Subversion in its present state. Out of the box, Subversion provides the ability to search for files that have changed since the last “commit”, or the last time changes were saved. Time Machine would just have to ask Subversion to report all the files that have changed, then run the commit. This could be scheduled to execute at a given time, say, midnight. In the event that the computer was off at the scheduled time, the steps could be executed immediately upon startup.

In the past, I’ve thought how nice it would be if all the files on my computer could go under revision control just like my source code when I’m working on an application. It would be just Apple’s style to make that possible not just for tech geeks who use Subversion, but to make it possible for anyone, even the guy who doesn’t care a lick about understanding revision control.

Those solutions are geared to respectively increase convenience. Bootcamp requires an inconvenient reboot. Then virtualization software allows us to boot up Windows without rebooting our Mac, and we can even use Mac apps and Windows apps simultaneously albeit with Windows in an encapsulated environment. Finally, CrossOver aims to take the convenience to the next level by eliminating Windows and enabling Mac OS X to execute Windows apps!

One article at LinuxWorld called CrossOver Office “the best way to do the wrong thing”. I contend that CrossOver is the worst way to do the wrong thing. If I have to run a Windows app on my Mac, I certainly want it to run as smoothly as possible, just like the rest of my Mac experience, and I want it to run like the developer intended. Largely, dual-booting and virtualization don’t compromise the behavior of the app I’m running. When you run your app with CrossOver, however, you don’t know what kind of performance you’ll get. Your app may just die; it may run but be full of bugs. The reports coming from the web show that your experience will be very hit-or-miss.

Don’t get me wrong; I’m not knocking the WINE project, which is the basis for the CrossOver codebase. A project to port the Windows APIs to another platform, although ambitious, is fascinating and, frankly, perfect as an opensource project. The problem I have is with the attempt to commercialize this technology that is great as a free resource but destined to never deliver a level of quality that befits a commercial product.

Why? There are so many variables and pitfalls to porting an API that the technology will never be able to work for even a large percentage of Windows apps, let alone all or the majority. And the technology can continue to be refined, only to see a Windows upgrade completely shatter the compatibility of future apps, and the development process of tweaking the port starts all over again. And from an opensource perspective, that’s fine. That’s the strength of an opensource initiative. It’s not such a great model for a commercial product.

What would you rather do? Buy CrossOver for $59 and be able to run only a few apps with it, and perhaps with a few bugs at that, or buy Parallels for $79 and be able to run practically all Windows apps with it, nearly bug-free? Of course, the price differential increases if you need to purchase a copy of Windows. Nevertheless, your experience will be infinitely more reliable if you use a virtualization solution like Parallels.

For the tech geek who likes tinkering with new software, this solution is worth a gander, especially while the free public beta is available. However, if you just need to get down to business, I recommend sticking with virtualization.

Please read his article: Apple on the Brink.

The premise is that Apple is “brain-dead” for not wanting to release OS X into the entire x86 jungle; yet, he opines, that is not what Apple really intends to do, and that, instead, Dvorak sees Apple’s bluff in his crystal ball.

And it really is a fantastic concept he has forecasted. I thoroughly enjoyed indulging myself in the unfolding of events that he described. As much as I would like seeing it happen the way he described, and as clever as Jobs et al have been of late, I find it very difficult to believe that the scenario that Dvorak has described is even remotely close to the truth. Frankly, I don’t think that he does either. Beware: This pat on the back is likely a slap in the face, if only we had turned around to pay attention.

This is Apple’s best quarter. Ever. Read about it: Apple Tops Its Quarterly Earnings Record.

One thing that is very encouraging about this is to see that the iPod is not the hero that saved the ailing team here. The iPod had a significant share, as expected, but it was just a team player on Apple’s championship team.

Other key players: Mac OS X 10.4 and Mac sales. Sure, we like it when the team keeps winning, even when these players were on the bench, but now that they’re back in the game–and exercising a killer instinct–the game is so sweet to see.

Mac OS X 10.4 was the best-selling software release in the company’s history; Mac sales experienced a 35% increase over last year; iPod sales had a “record quarter” for the ninth time in a row. When all the key players score triple-doubles, the fans just go wild.

And the timing couldn’t be more perfect, since Apple’s sales my go into slight hibernation as the world awaits the first x86-based Mac. But that’s okay–Apple is ready.

It is mentioned in: Jobs rebuts eco-group claims at annual meeting.

According to MacWorld, when Jobs was asked about the release of Mac OS X Tiger and the upcoming Longhorn, he said, �They are shamelessly trying to copy us…I think the most telling thing is that Tiger will ship at the end of the month and Longhorn is still two years out. They can�t even copy fast.�

What a great line!

Please read: Mac Industry Heeds Tiger’s Roar.

It is noteworthy that Apple and Microsoft have both been pursuing metadata and better ways to provide searchability, and yet Apple is delivering in early 2005, whereas experts’ confidence that Microsoft will deliver by sometime in 2006 is slipping.

Apple has taken a dominating role in delivering a truly modern operating system via Darwin and OS X 10.4.

Unfortunately, truly modern operating systems are not always what businesses are looking for, which is one reason why Apple’s dominance hasn’t transferred to market share in the business industry. Nevertheless, Apple continues to impress experts and home users alike.

In addition to the general fine-tuning of the core technologies driving OS X, I am looking forward to see how OS X 10.4′s new technology Spotlight will improve the usefulness of the Mac desktop. This is the feature that feels most futuristic and high-tech. It may seem silly to refer to a basic search functionality as “futuristic” or “high-tech”, but really search technology has come a long way even in just the past 5 years, and we’ve come to see that innovative and intuitive searching is actually quite hard to come by. I am hoping that Spotlight will provide a sophisticated and intuitive interface to this end.