Most Mac users know if they want to know what’s “under the hood” of their Mac, they could boot into the OS, click on the Apple logo, and click “about this Mac”. But, did you know you could go into Terminal, and type in “hostinfo” and hit enter? The command host is usually used for […]
We’re taking a little break from Cryptocurrency in this edition of Tech Tails. But fear not, fellow investors! We’ll get back to it next edition.
Lately, I’ve been fielding a lot of customer questions regarding APFS, Apple’s latest file system format so let’s talk about format types.
APFS is the latest file system format Apple released this past year. When you install macOS High Sierra on the Mac volume of a solid-state- drive, that volume is automatically converted to APFS. Fusion Drives, traditional hard disk drives (HDD’s), and non-Mac volumes are not converted. APFS carries a huge advantage as the format type can replace all of the existing file systems Apple currently uses across its platforms. APFS is suitable for macOS, iOS, tvOS and even watchOS.
Mac OS Extended (Journaled) is the default file system format for Mac OS drives. Formatting a drive with this will give you full interoperability with Macs. You can even set up a macOS startup drive if you have the right files, the know-how, and a large enough drive. The downside to this format is the compatibility between Mac and PC. A drive formatted as Mac OS Extended can be read by a PC, but the user will be unable to write data onto the drive. If you’re transferring files from Mac to PC this won’t be an issue, but going from PC to Mac in this format won’t work.
MS-DOS (FAT) is Disk Utility’s name for the FAT32 file system. FAT32 offers near-universal interoperability with every computing system. A drive formatted this way can easily transfer files between Mac and PC. The drawback to this format is FAT32 does not support files larger than 4 GB.
ExFAT essentially carries the advantages of FAT32, and bolsters this by supporting files larger than 4 GB. If transferring large files between Mac and PC, this format is for you.
Most Mac users know if they want to know what’s “under the hood” of their Mac, they could boot into the OS, click on the Apple logo, and click “about this Mac”.
But, did you know you could go into Terminal, and type in “hostinfo” and hit enter?
The command host is usually used for DNS lookup and info but you can use it to find out which kernel version you’re running, how many processors you have, the amount of physical memory and the number of Mach tasks. Mach tasks are a variant of the load average, number of threads using.
The syntax looks like this
hostinfo
That’s it, there are no further options as it is a simple command. We Techs use it a lot when performing RAM upgrades and when we don’t want to wait for the Mac to boot all the way into the MacOS to see if the RAM modules are recognized.
Shut down the Mac completely, and wait a couple seconds. Then, hold down the Command and S keys simultaneously while pressing the power button to start up the Mac. You’ll hear the chime, and then a black screen will appear. Shortly thereafter, a bunch of scary white text will show up. This is single-user mode.
Here you simply type “hostinfo” and you’ll see something like this:
Mach kernel version: Darwin Kernel Version 16.7.0: Thu Jun 15 17:36:27 PDT 2017; root:xnu-3789.70.16~2/RELEASE_X86_64 Kernel configured for up to 8 processors. 4 processors are physically available. 8 processors are logically available. Processor type: x86_64h (Intel x86-64h Haswell) Processors active: 0 1 2 3 4 5 6 7 Primary memory available: 128.00 gigabytes Default processor set: 377 tasks, 2201 threads, 8 processors Load average: 1.95, Mach factor: 6.04
This outlines the following information about your machine:
When you’re finished exploring this info, simply restart you computer by typing:
reboot
This info is the tip of the iceberg of the information you can coax out of your machine from the command line but it’s a good way to get your feet wet to explore what’s possible.
If you pay any attention to technology news, you’ve probably already heard of the recently discovered Meltdown and Spectre exploits that are reported to effect a majority of computer systems currently in operation, regardless of their operating system. Since the vulnerability is at it’s core, hardware-based, users of Macs, PC’s and some mobile devices are […]
If you pay any attention to technology news, you’ve probably already heard of the recently discovered Meltdown and Spectre exploits that are reported to effect a majority of computer systems currently in operation, regardless of their operating system. Since the vulnerability is at it’s core, hardware-based, users of Macs, PC’s and some mobile devices are all at risk equally. The hardware in question are processors by Intel, AMD and ARM and the issue could be exploited in 3 ways known as Variants 1 and 2 (identified as Spectre) and Variant 3 (identified as Meltdown).
The way the Spectre exploit works is by taking advantage of the way your computer processor’s architecture is wired to execute code. In a very basic way, the processor’s job is to make a series of decisions very quickly and pass along the results of those decisions. To speed things up, most modern processors use a technique known as “branch prediction” to guess what the next decision it’s going to have to make is. This “speculative execution” greatly improves the speed of a processor as it can always stay a few steps ahead of the game. It’s not always correct in it’s predictions, but that doesn’t matter because the speed at which it does these predictions allows it to perform many, many of these per second.
In very simple terms, it’s all of these incorrect predictions that allow your sensitive data to be potentially revealed. When these bits of data are trashed, for just a moment, the state of your processor can be analyzed by some malicious agents and backtrack it’s way to what bits of data were used to arrive at it’s incorrect prediction. It can then exploit this method by making your processor arrive at incorrect predictions on purpose by injecting data far outside the bounds of what it expects and, in turn, grabbing more of your sensitive data with each execution.
Patches to guard against this involve an extra step every time your computer executes these kind of instructions, double checking to see if the data it’s executing lies within the bounds of what’s expected as well as separating the code and predictions into separate areas of memory. Different processor models have slightly different architectures and the exploits work in slightly different ways across them, however this is generally how things work.
Meltdown is much more clear-cut exploit. To run efficiently, data being run through different parts of your computer processor is stored in a cache as it’s passed between sections of your processor. Meltdown reads this cache and can take the information contained in it and send it off in another direction to be utilized for nefarious purposes. The fix for this involves splitting the address space for this shared memory so that the data is never complete and would appear as gibberish if it were captured, the downside to this fix is that it involves making your computer do twice the work for the same amount of processing. Fortunately, this type of shared memory space only occurs in an impactful way during specific I/O events such as disk-reads or network communication and has little effect on computationally-heavy computing such as video-editing or gaming.
New chipsets and operating-systems should be affected very minimally by any patches to eliminate these exploits, however older systems and certain cloud and virtualization computing systems could take a pretty big performance hit as they rely heavily on I/O to operate.
It’s not often that we see such a vulnerability so widespread and so tricky to fix. It’s something that has been baked into the core architecture of so many of our computer systems in slightly different ways and yet it exists almost universally between manufacturers. It’s like suddenly discovering that bare lightbulbs can steal your credit card number. Sure you can just say “use a lampshade” but lightbulbs come in different sizes and styles even though they all work pretty much the same way and even if you design a lampshade for every bare lightbulb out there, there will be slightly less light when fitted with a lampshade.
Greetings, fellow traders!
As always, it’s been quite an unpredictable last few weeks in the world of Crypto. While Bitcoin has remained somewhat stagnant around ~$14k, Ethereum hit an ATH (an all-time high) of $1000 per coin! This was an especially happy moment for me as ETH was actually the first cryptocurrency I chose to invest in several months ago. Other big news too – relative newcomer altcoin Ripple (XRP) briefly unseated ETH for the number 2 spot on the Cryptocurrency Market Cap before settling down to the #3 position when ETH edged closer to that $1k mark. Not everyone is pleased with XRP, however. Ripple has been catching some flack for not being a “true” cryptocurrency. Some folks out there believe that in order to be considered an alternative currency, the currency must be decentralized. As you might’ve guessed, XRP is a centralized currency. It has an organization, a CEO, employees, etc. and rumor has it it’s being bought up in droves by US banks. It certainly seems like it’s here to stay regardless of the widespread consensus. While it does go against the grain of the definition, and drumming up controversy among would-be traders, that’s not keeping me from investing in it! As anyone who trades coins spends their time sifting through pages and pages of “white papers” and forums or checks their phone religiously for price updates, etc. will tell you: it’s quite a fun ride.
In the last week’s Techtails, we touched briefly on Bitcoin transactions, but HOW does this transaction occur?
Let’s backtrack and break it down step by step.
Connor sends Don 1 BTC in exchange for a real nice, real sweet 15” MacBook Pro, (again, the current value of 1 BTC as of today’s writing stands at ~$15k.) He does this by essentially going to his BTC wallet, grabbing his wallet address or “private key”, (the input) where his BTC is stored. (An address/public key resembles a random string of alphanumeric characters that identifies where to draw the BTC from. Every wallet address or public and private key is different.) He then designates the deposit total of 1 BTC to Dons “public key”, (the output), and confirms the payment. Within a few moments, Don will receive 1 BTC and Connor walks out with the Holy Grail of MacBook Pros.
So that explains how the transition works, but doesn’t tell us what exactly happens on the backend of that transaction. Cryptocurrency at its core is supposed to be about transparent financial dealings, right?
Yes!
Once Connor hits that “Send” button on his phone (yes, you can do these transactions right on your phone), so begins a process that is truly the magic of blockchain technology.
The MacBook Pro transaction is then broadcast to the Bitcoin network where “miners” verify that Connor’s keys are able to access the inputs (the address from where he withdrew his BTC) he claims to control. This process is known as “mining” because it requires resource intensive computational labor and actually rewards miners in BTC per block solved. The protocol behind mining BTC is dense, but to put it in terms that are easy to digest, mining is a peer-to-peer computer process used to secure and verify BTC transactions. Each group of transactions is called a block. Blocks are secured by BTC miners and build on top of each other forming a chain. Block. Chain. Blockchain. And the blockchain contains a ledger of every single BTC transaction that has ever taken place. While that sounds distressing, there are no names or identities tethered to these transaction blocks. So, if you were to download the entire BTC ledger to your computer, and yes it can be done, you would theoretically be able to track down the transaction record we described above. Pure. Transparency. Blockchain!
This was a refresher on last edition’s BTC transaction., Next week we’ll pickup where we left off and delve further into the process and function of mining.
‘Til next time, fellow traders!
Winter is here and if you are not lucky enough to live in a milder climate, you need to take extra precaution when using your computer. I am sure some of you have left your computer in the cold car overnight. Leaving your computer or iPhone in cold temperatures below 32 degrees Fahrenheit for an extended period of time can cause damage. This could be dangerous if extra steps are not taken in the care of your device.
Cold temps affect most batteries as they will lose their charge quicker in the cold. It is not uncommon to see temporary poor battery performance in your computer when using it in colder conditions. Once you resume working in warmer temperatures (approximately 50-90° Fahrenheit) you should have normal performance. But why? Due to higher internal impedance, the external temperature affects the battery’s ability to create the chemical reactions to produce a charge. Short term this does not have lasting damage, but if you use your computer in the cold on a regular basis you will start to see long term poor battery performance.
Poor battery performance is only a minor effect of extreme cold exposure. Condensation can cause liquid damage. We’ve all seen someone who wears glasses come in from cold temperatures and have their glasses immediately fog up. That’s essentially what could be happening inside your computer. If your computer warms up too quickly it can trigger the LCI or liquid contact indicators within your computer to signal your computer has been exposed to water and, if you don’t have AppleCare+, potentially a costly repair. So what do you do? If bringing your Mac in from an overnight stay in the cold, let the machine sit for at least 30 min before powering on. This should prevent any condensation issues and allow your computer to gradually adjust back to the warmer indoor temperatures.
