In Finksburg, Maryland, Route 140 is heavily patrolled. Breaking the speed limit would likely lead to a fine.

But some speed limits can't be exceeded, no matter how much one wishes to. The speed of light comes to mind. As does the speed at which a teenager's brain matures.

Then there are multiprocessor limits. Amdahl's Law tells us that the max speedup achievable is:

where f is the percentage of a problem that cannot be parallelized, and n is the number of processors. In a system, where, say, only 50% of the problem can be executed in p......

[Continued from My favorite quirky chips (Part 1)]

The first bit of strangeness was the package, an enormous 50-pin DIP (old-timers will remember the first 68000, which was in an equally-huge 64-pin DIP). That allowed for separate instruction and data buses, and some claim that this was the first micro with a Harvard architecture. Instructions were 16 bits, with 13 address bits, and the data bus was just a byte wide.

It gets odder. The data bus was called the "Interface Vector bus," or IV for short, and bit 7 was the LSB! IV0 to IV7 were multiplexed with both addre......

In some of my previous blogs, I outlined the history of the microprocessor. Two of the important developments were the Williams tube and the Whirlwind computer. Although the Whirlwind originally did use Williams tubes, it became the first machine with core memory. After those articles appeared, I visited London's Science Museum and took pictures of a Williams tube and a Whirlwind core plane (shown right). Alas, my camera skills are very poor, but the crude memory densities are startling: each of those cores, spaced about a quarter of an inch apart, stored a single bit.

Text messaging has been dubbed as a killer app, and indeed it is, when one uses it behind the wheel. It seems developers are continuing to build apps that turn some of us into sociopaths.

According the Physorg science and technology news service researchers—apparently desperate for grant money—at a couple of universities have come up with an app that uses the phone's camera to alert the user that a car is approaching. Yeah, perhaps this is useful for the disabled (though that is not mentioned in the article) but what happened to looking where you're walking?......

In one of the recent posts in his site The Understatement, Michael Degusta says that many Android phones, even some actively for sale today, generally don't have an upgrade path to the latest version of the OS. (The chart on that site is an example of the brilliant use of graphics to convey a lot of information.)

iPhones, in stark contrast to the 18 Android devices he examines, always support the latest version of iOS (as long as the user bothers to install the update).

Interestingly, seven of the phones neverran a current version of Android, even when first released.

In the "Holy Crap What's Next?" department, Xilinx recently launched a new FPGA. Yawn, right? Well, this device is pretty amazing.

Comprising 6.8 billion transistors, it offers 1,955,000 logic cells, which is equivalent to maybe 20m gates. There's 46,512 Kb of Block RAM on-board. Tons of I/O is included, like 36 serial transceivers each capable of running at 12.5Gb/second.

Amazing fact number one: this high-end variant of Xilinx's 28nm Virtex-7 family includes 2,160 DSP slices, each of which looks like this:

(From......

[Continued from A look at the semiconductor revolution (Part 1)]

The market for computers remained relatively small till the PDP-8 brought prices to a more reasonable level, but the match of minis and ICs caused costs to plummet. By the late 1960s everyone was building computers. Xerox. Raytheon (their 704 was possibly the ugliest computer ever built). Interdata. Multidata. Computer Automation. General Automation. Varian. SDS. Xerox. A complete list would fill a page. Minis created a new niche: the embedded system, though that name didn't surface for many yea......

[Note: Here's the third installment of Jack's series honoring the 40th anniversary of the microprocessor. Read part 1 here and part 2 here.]

Here's quote from Pat Gelsinger, Intel, 2002:
"We're on track, by 2010, for 30GHz devices, 10nm or less, delivering a tera-instruction of performance"

We are all aware of how Shockley, Bardeen, and Brattain invented the transistor in 1947, ushering in the age of semiconductors. But that common knowledge is wrong. Julius Lilienfeld patented devices that resembled field-effect tr......

I was having a chat with John Carbone at the Boston ESC about tools. John's company, Express Logic, sells a real-time operating system and associated add-on components. We were talking about the reluctance of so many developers – or, more often, their bosses—to spend money on decent tools and resources.

John used an interesting analogy: you can get a nearly-free ax to cut down trees. It will work great! Who can argue with Honest Abe's success with the ax?

Or, spend hundreds of dollars and get a chain saw to clear dozens of trees while a Paul Bunyan with......

Here's a quote from Popular Mechanics, 1949:

Where a calculator on the ENIAC is equipped with 18,000 vacuum tubes and weighs 30 tons, computers in the future may have only 1,000 vacuum tubes and perhaps weigh 1-1/2 tons.

November marks the 40th anniversary of the microprocessor, the circuit element that truly revolutionized the world and gave birth to the field of embedded systems. This is the second installment about this historic development. You can find the first here: The microprocessor at 40—The beginning of electronics (Part 1)

Thomas Edi......