Charles Petzold Quotes

NOP stands for (and is pronounced) no op, as in no operation. The NOP causes the processor to do absolutely nothing. What's it good for? Filling space. The 8080 can usually execute a bunch of NOP instructions without anything bad happening

You're twelve years old. One horrible day your best friend's family moves to another town. You speak to your friend on the telephone now and then, but telephone conversations just aren't the same as those late-night sessions with the flashlights blinking out Morse code. Your second-best friend, who lives in the house next door to yours, eventually becomes your new best friend. It's time to teach your new best friend some Morse code and get the late-night flashlights blinking again.

Code is not like other how-computers-work books. It doesn't have big color illustrations of disk drives with arrows showing how the data sweeps into the computer. Code has no drawings of trains carrying a cargo of zeros and ones. Metaphors and similes are wonderful literary devices but they do nothing but obscure the beauty of technology.

To a programmer, an operating system is defined by its API.

Bits also play a part in logic, that strange blend of philosophy and mathematics for which a primary goal is to determine whether certain statements are true or false. True

a digital design engineer, you would spend long hours going through the TTL Data Book familiarizing yourself with the types of TTL chips that were available. Once you knew all your tools, you could actually build the computer I showed in Chapter 17 out of TTL chips. Wiring the chips together is a lot easier than wiring individual transistors

When the iPhone app is built, the Xamarin C# compiler generates C# Intermediate Language (IL) as usual, but it then makes use of the Apple compiler on the Mac to generate native iPhone machine code just like the Objective-C compiler. The calls from the app to the iPhone APIs are the same as though the application were written in Objective-C. For the Android app, the Xamarin C# compiler generates IL, which runs on a version of Mono on the device alongside the Java engine, but the API calls from the app are pretty

In some far-off distant time, when the twentieth century history of primitive computing is just a murky memory, someone is likely to suppose that devices known as logic gates were named after the famous co-founder of Microsoft Corporation

communication simply requires

In 1948, while working for Bell Telephone Laboratories, he published a paper in the Bell System Technical Journal entitled "A Mathematical Theory of Communication" that not only introduced the word bit in print but established a field of study today known as information theory. Information theory is concerned with transmitting digital information in the presence of noise (which usually prevents all the information from getting through) and how to compensate for that. In 1949, he wrote the first article about programming a computer to play chess, and in 1952 he designed a mechanical mouse controlled by relays that could learn its way around a maze. Shannon was also well known at Bell Labs for riding a unicycle and juggling simultaneously.

Many MIDI files contain entire musical compositions. Because MIDI supports only 16 channels, however, no more than 16 different instruments can play at any time, and one of those is the key-based percussion instrument.

All modern MIDI synthesizers are capable of polyphony, which means they can play more than one note at a time and more than one instrument at a time.

Some programs - especially games - require that your system be set to a particular color depth and resolution. Often such special settings are different from your usual mode, though.

I started out with machine code and assembly language.

MIDI made a natural transition to the PC. The MIDI messages that make up a musical composition can be saved as MIDI files, which are collections of MIDI messages with timing information.

Free lunches don't come cheap.

Computer monitors can operate in many different video modes. In most cases, the decision about how many pixels and colors to display is yours - but not always.

I really liked figuring things out on my own. Early on in the development of a new version of Windows, I would explore it, I would try out various things, I would see what worked, I would see what didn't work.

Programming in machine code is like eating with a toothpick

The human species is often amazingly inventive and industrious but at the same time profoundly lazy. It's very clear that we humans don't like to work. This aversion to work is so extreme - and our ingenuity so acute - that we're eager to devote countless hours designing and building devices that might shave a few minutes off our workday

I felt more like a scientist exploring nature, and Windows was my environment. You don't pass judgment on nature; you just explain how it works.

Some people believe that Moore's Law will continue to be accurate until about 2015.

I said early on in this chapter that we would need 144 relays for our adding machine. Here's how I figured that out: Each