Krav Maga for Teens

My 11 and 13 year old boys have been enrolled in Dynamic Krav Maga's teens programme for the last month. I have to say I am very impressed by what Aaron is doing. Over the last few years while living in Montreal, my two boys and their sister have participated in other martial arts programmes, namely Karate and Whu Shu. The formality of Karate and the pressure to test for belts were big turnoffs and seemed like cash grabs. Whu Shu was good for a while and it was cool watching my then seven year old daughter doing the moves, but she too became disinterested after a while because of the lack of practical applications.

What is different about Krav Maga?

Krav Maga was founded on the need for practical self-defense against the fascists in Eastern European Jewish ghettos in the 1930s. It was subsequently incorporated into the Israeli Defence Force training programme. The whole back story is available on the Wikipedia page.

Why is Krav Maga good for teens?

• Practical self-defense
• Develop confidence
• Fitness

What is the class like?

Adult Krav Maga training involves quite a bit of aggression and strong language, as "fighting dirty" is a big part of the tactics. Thankfully, the teen programme at Dynamic Krav Maga has been toned down to be more appropriate for the impressionable young minds.

Source: blogbyjoe.thenetexpert.net via Joseph on Pinterest

The class starts with warm up consisting of running around and practising some basic moves from previous classes. Then Aaron will present scenarios where new moves can be applicable. It is all very centered on being practical and often built on previous lessons. The new moves are practiced to be committed to muscle memory. The tactics are focused on deflect-then-flee and developing situational awareness (e.g. are there more attackers/bullies), rather than sticking around to pummel all the baddies. The final 15 minutes of the class consists of games to apply moves learned so far. This is usually my boys' favourite part of the class. The entire class takes less than an hour, but everyone gets a good workout and have fun learning practical self-defense skills.

Take a look at this video on why kids should learn Krav Maga

Krav Maga for teens in West London

If you are a parent of teenagers in West London and Krav Maga sounds interesting to you, please head on over to the Dynamic Krav Maga website to register your interest with Aaron. Maybe we will see you on Thursday night!

Best home or small office broadband routers

I am playing with list.ly but I am also curious to know what are your favourite home or small office broadband routers...

Best home broadband router

View more lists from Joseph Chin

Supercapacitors to the Rescue

Batteries (lithium ones that is) have been getting a bad rap in the press for the last month because of all the kerfafle with the grounding of the wonderful new Boeing 787 commercial jetliners after a couple smoky electrical incidents.

Well, a solution may be near - Supercapacitors. Imagine charging your iPhone for 30 seconds to store up enough charge for the entire day! This can be applicable for everything from our smartphones to electric cars to passenger jets. It really shines in high charge-discharge applications, such as electric hybrid drivetrains. All this with a technology that will be friendlier to the environment than the batteries we have today, and supercapacitors will likely outlast the host devices they power.

A bit more development is required before supercapacitors gain widespread adoption in consumer devices. But it is already being used in large scale industrial/commercial/military applications. The biggest breakthrough at the moment is the announcement by UCLA researchers that they have successfully fabricated graphene based supercapacitors using nothing more than a consumer brand DVD burner. So I am sure we will see supercapacitor-powered consumer devices on the market very soon.

Without further ado, check out the following video ...



Read this article for more information about the application of supercapacitors.

Checking out Pinterest

So I decided to spend a few minutes checking out Pinterest and uploading a few photos. It is quite addictive. Check out my pins and boards. For some reason, I find Pinterest more appealing than Instagram. Maybe I will expand on it in the coming days/weeks once I understand it better.

A week with DIY Apple Fusion Drive on my 2011 Mac Mini

So far so good

It has been a week since I setup my do-it-yourself Apple Fusion Drive. The little Mac Mini is still impressively fast. And it is so quiet, and the Mac Mini is a pretty quiet system to start with. I have gotten so used to this new level of performance and refinement that I get disappointed when I arrive at the office to use an (2010) iMac that up until last week, had been my favourite desktop computer.

What still concerns me?

If one of the SSD or hard drive dies, the Mac Mini will become unusable. Like RAID-0 striping, if one member of the Fusion Drive volume should become unavailable, the entire Fusion Drive is hosed. Granted I have no real knowledge about how Fusion Drive would recover from the loss of a member, but it is obvious you can't recover data that is not physically accessible.

How do I stop worrying?

Twice weekly scheduled replication with SuperDuper to the external Firewire drive. And backing up all the important files to Crashplan.

What I wish for?

Better diagnosis and monitoring. There is NO diagnosis and monitoring facility in Fusion Drive that I am aware of. I suppose I can do iostat disk0 disk1 5 but that doesn't tell me how much of the SSD is utilised or how much of each active file resides on the SSD or how much of the read/writes have been optimised over just plain ol' spinning rust.

More information about Fusion Drive

Patrick Stein's blog is a treasure trove of information about Fusion Drive. It is unfortunate that Apple hasn't seen fit to share any information about the inner workings of the Fusion Drive. But through the persistence and generosity of the like of Patrick, there is a decent amount of technical information that can be revealed with a bit Google'fu.

My new blog on IT and technology

I have decided to setup a separate blog to focus on IT and technology topics. Does this world need another technology blog? There is no denying there are plenty of great technology blogs out there. The purpose of my blog is an attempt to contribute to the Internet community after years of benefiting from the consumption of other people's work on the Internet. I think there maybe room for a blog that provides concise to-the-point useful articles. Lets see if I can deliver on this simple goal. The first post is a brief introduction on my technology background. The second post describes my recent experience setting up Apple Fusion Drive on my Mac Mini. Please take a look at the blog and let me know if you find it interesting or useful (or both). Thanks!

Taking my 2011 Mac Mini to a new level of performance with DIY Fusion Drive

The Background

I purchased a Mac Mini Server configuration (quad-core i7, two 750GB 7200-rpm hard drives) in December 2011 to be used as the family media centre computer connected to the flat panel TV. But it didn't see much use as the family preferred the Apple TV with Netflix and other media streamed over the web. So I bought a 24" AOC IPS display and repurposed the Mini as my home office computer for web surfing duties and running a Windows 7 virtual machine on the very capable Parallels Desktop hypervisor. I soon realised that 8GB RAM wasn't enough to sustain an acceptable level of performance if I was to also run additional Mac applications (e.g. iPhoto, iTunes, Evernote) as well. It wasn't that expensive to upgrade to 16GB RAM, and in return, I got what felt like a newer more powerful computer! Fast-forward a year, the Mini was still fit-for-purpose, but I had taken to running Linux in another virtual machine and the hard drive storage seemed much fuller. I noticed the system was constantly thrashing the hard drive and I was spending more time watching the spinning wheel on the screen. I remembered the mention of Apple Fusion Drive during the Fall 2012 Apple product announcements. It seems like a decent idea and not unlike the storage-tiering concept that is common place in the enterprise storage systems I have implemented in my day job. I found a very good article on Anandtech about the inner workings and general experience with Fusion Drive. There were also many other articles about Do-It-Yourself Fusion Drive for older Macs, in particular this post from Rick Kasguma. This provided all the information I needed to move ahead with the project to take my Mini's performance to a new level.

Executing The Plan

After some research, I decided to purchase a SanDisk Extreme 240GB SSD based on its very good band-for-the-buck performance as reported by this StorageReview.com post and others. Note that my Mac Mini's two internal hard drives were not configured for RAID-1 mirroring as all important files were already continuously protected by automated uploads to Crashplan cloud storage and I didn't want the possibility of logical storage corruption propagating across two drives. Instead, I had SuperDuper configured to replicate the main hard drive to the second hard drive a couple times a week, and I also manually replicated the main internal hard drive to a 1TB external Firewire hard drive at least once each month. This strategy complies with the "123 rule of backup" - 1 copy off-site, 2 types of storage media, 3 copies of data.

You probably know by now that I am a big fan of SuperDuper. I have been using this product for at least 5 years to make sure I have bootable replicas of my Mac startup disks. I can't believe the decent folks at Shirt Pocket do not charge more than £20 for this awesome product that just works! Btw, I get no commission from them nor am I an affiliate in anyway. So I am just a very happy (and sometimes very grateful) customer.

Anyways, the following is the plan as executed for this upgrade project:

1. Get SanDisk Extreme 240GB SSD
2. Upgrade internal 750GB boot drive to OS X Mountain Lion
3. Use SuperDuper to replicate upgraded OS X Mountain Lion volume to external Firewire drive
4. Use SuperDuper to replicate upgraded OS X Mountain Lion volume to second internal drive
5. Create OS X USB restore key per straightforward instruction here
6. Verify boot of USB restore key
7. Verify boot of external Firewire drive
8. Install SSD in Mac Mini, replacing the first internal 750GB boot drive hard drive. Very good instruction video.
9. Boot off external Firewire drive
10. Setup Fusion Drive. This is pretty straightforward if you are comfortable working in the Linux/UNIX or OS X command line. Buy your favourite Linux/OSX geek a beer to take care of this if you don't want to deal with this yourself. There are plenty of instructions on the Internet (Google "DIY Fusion Drive") so I am not going to repeat the details here. To summarise, the steps and commands will look something like this:
    1. diskutil cs create fusion disk0s2 disk1s2
    2. diskutil cs list and take note of the Logical Volume Group ID
    3. diskutil coreStorage createVolume jhfs+ Fusion 100%
11. Install OS X Mountain Lion on new Fusion Drive
12. Use SuperDuper to restore OS X Mountain Lion volume from external Firewire drive to Fusion Drive. It is very important to use SuperDuper "Smart Update" so it won't erase and corrupt the Fusion Drive partition.
13. Enable TRIM support with Trim Enabler
14. Setup SuperDuper to replicate (internal) Fusion Drive to above 1TB external Firewire drive every Tuesday and Saturday
15. Manual SuperDuper replication of Fusion Drive to another external drive
16. Make sure Crashplan is backing up important files to the cloud

I Love It When A Plan Comes Together

Well, it has been several days since the upgrade to the DIY Fusion Drive on my Mac Mini and I cannot be more satisfied with the performance improvement! It used to take up to 5 minutes for the system to startup completely with all the applications loaded, including iTunes, iPhoto and the two Parallels virtual machines. Now it takes much less than a minute! Applications startup in a few quick seconds instead of 10s of seconds, especially for big ones such as Microsoft Office applications. Overall, almost all applications seem to be generally more responsive in their operation. Another benefit is that the Mac Mini seems to run quieter and cooler with the much lower power consumption SSD and the remaining internal hard drive not thrashing as before.

Additional Thoughts

As good as the Fusion Drive looks, there is an element of risk that much be understood. Fusion Drive is not a caching solution that uses the SSD to accelerate the hard drive. It behaves more like a tiered storage system where frequently access data blocks/chunks are "promoted" to the fast SSD and less accessed data blocks/chunks are "demoted" to the slower bulk storage hard drive. Like RAID-0 striping, if either the SSD or the hard drive should become inaccessible for whatever reason, the entire Fusion Drive volume will be unusable. Any time you add more bits into a system, you are more likely to increase the possibility of failure in the chain of operation. Another point of concern is the longevity of SSD as it is well known by storage techies that the mass market MLC SSDs have fairly limited write endurance. That said, SSD manufacturers have implemented all sorts of secret sauces in their controllers to improve the write endurance of their products. This is why it pays to buy the latest high quality SSD your budget allows. In any case, you are responsible for backing up your data following the practice of the aforementioned "123 rule of backup" regardless of the risk profile of your storage system.

The official Apple Fusion Drive option in new iMacs and Mac Minis consists of 128 GB SSD paired with a 1TB or bigger hard drive. This means the SSD to hard drive (i.e. fast to slow) storage ratio is around 1:8 or worse. This is probably adequate for most use cases consisting mainly of web surfing and productivity (e.g. MS Office) applications. Based on the articles and test results I have come across, Fusion Drive storage performance can degrade to hard disk-like level if the aggregate active data blocks/chunks consistently exceed the capacity of the fast tier of storage (i.e. the SSD). So it helps to have some understanding of the size of your expected active working data set. In my case, my iPhoto and iTunes libraries are around 100 GB total, the virtual machines are another 100GB, so I think the 240 GB SSD should be more than adequate after factoring additional space for the operating system, other applications, and write caching (all writes go to SSD first). Also keep in mind that in most cases, Fusion Drive does not need to "promote"/"demote" entire file across the storage tiers, it can do it in "chunks" or subsets of the files. This means for most use cases, it is not necessary to install big (and more expensive) SSDs.

The Bottom Line

Lets be clear, the Apple Fusion Drive is nothing new nor entirely innovative. It is a concept that has existed in enterprise storage systems for a long time. Software and hybrid software/hardware (e.g. Intel SRT) based storage caching solutions leveraging SSD have been available for PCs/Windows systems for quite some time as well, but have so far failed to be implemented in any significant scale and seem like rather half-hearted effort. I have installed a Seagate Momentus XT hybrid hard drive with 8GB flash memory cache in the kids' Windows laptop many months ago. Though the performance improvement has been somewhat perceptible over the old hard drive, it hasn't been anything to get excited about.

Apple's accomplishment with the Flash Drive is in making it available to the masses (who use Apple Mac computers) in a simply packaged option that produces dramatic improvements in perceived performance. Better yet, this technology is available any older Mac computers that can be upgraded to run OS X Mountain Lion. Do I recommend the Apple Fusion Drive? You bet I do!


Also see follow up post.

Welcome!

Welcome to my new technology blog. This is where I hope to share my findings and thoughts in the exciting world of computer and Internet technologies.

Who am I?

I am a technology enthusiast with more than 25 years working experience in the Information Technology industry. I have worked in roles ranging from PC technician to building global IT operations group and leading an R&D team. I have worked on many exciting bleeding-edge projects, including building high efficiency data centres at exotic locations before the term green computing was coined. I have worked with and learned from many very intelligent and dedicated people. I have witnessed the amazing progress of the Internet over the last 20+ years and I have also experienced some of the lows (e.g. DDoS for ransom). I have experienced the stings of corporate back-stabbers on their way up the ladder, but I also shared the pride of assembling a global team of brilliant minds. Through it all, I have never lost sight of my love of technology - its ability to inspire and innovate.

Why blog?

This blog is one of my attempts to share the knowledge I have learned from many years of technology experience. I have benefited greatly as a consumer of information on the great Internet. This is the opportunity for me to payback a little while learning more in the process.

You can also find out more about me by check out my LinkedIn, Twitter, and Paper.li links to the right of this post.

Please also check out my general blog where I intend to cover primarily non-IT topics, such as investment and travelling. But some posts can still be technical in nature as I write about my interests in aviation, motor sports, high performance sailing, etc.

I am not one for epic posts containing a ton of details. I prefer information that are to the point and can be absorb quickly. So my posts will mostly be quite short. I hope you will enjoy reading my posts as much as I enjoy writing them. I welcome all constructive feedback.