The Daily Parker

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C is for Common Language Runtime

Blogging A to ZDay 3 of the Blogging A-to-Z challenge brings us to the heart of .NET: the Common Language Runtime (CLR).

Microsoft defines the CLR as the run-time environment which "runs the code and provides services that make the development process easier." That isn't the most helpful definition, so let me try to elaborate.

As I described Sunday and yesterday, the .NET compiler takes your source code from C# or whatever other language you use and compiles it down to one or more managed modules containing intermediate language (IL), which get further compiled into assemblies.

When your program runs, the CLR is the thing running it. It loads your assemblies and then handles all the tasks your program needs to survive, like memory management, thread synchronization, exception handling, security, etc. It actually does this through Just-in-Time compilation (JIT), when it translates the IL into your machine's own language. This means that when an IL instruction is executed for the second time, it runs in native CPU code.

The CLR also manages .NET's common type system (CTS), which "defines how types are declared, used, and managed in the common language runtime," according to Microsoft. Types (my topic for April 23rd) are therefore a part of every .NET program, even (gasp!) Ruby.NET. I'm picking on Ruby because in that language, ever instruction gets interpreted at run time, making it possible to use types that you haven't defined. The CLR and the CTS prevent you from doing that.

To learn a lot more about the CLR, I strongly recommend Jeffrey Richter's CLR via C#, which I mentioned Sunday.

B is for BASIC

Blogging A to ZFor day 2 of the Blogging A-to-Z challenge, I'm going to talk about the first computer language I learned, which is still alive and kicking in the .NET universe decades after it first appeared on a MS-DOS 1.0 system disk: BASIC.

BASIC stands for "Beginner's All-Purpose Symbolic Instruction Code." The original specification came from John Kemeny and Thomas Kurtz at Dartmouth College in 1964. Today it's one of the core .NET languages included with Visual Studio as "VB.NET" (for "Visual BASIC," Microsoft's dialect of BASIC released in 1991).

Yesterday I showed you a "Hello, World" application written in C#. (You can download the source code here.)

Here's the VB.NET version:

Module Program

	Sub Main()
		Console.WriteLine("Hello, World!")
		Console.ReadKey()
	End Sub

End Module

What's different? Well, a lot of things: no braces, no include lines, no semicolon line endings...and that's just for a 2-line program.

But look at what's the same. Because this is a .NET program, the actual guts of it look almost exactly the same. There are two calls to different methods on the Console object, and except for the missing semicolons, they are identical to the calls in C#.

Here's the IL:

.method public static void  Main() cil managed
{
  .entrypoint
  .custom instance void [mscorlib]System.STAThreadAttribute::.ctor() = ( 01 00 00 00 ) 
  // Code size       19 (0x13)
  .maxstack  8
  IL_0000:  nop
  IL_0001:  ldstr      "Hello, World!"
  IL_0006:  call       void [mscorlib]System.Console::WriteLine(string)
  IL_000b:  nop
  IL_000c:  call       valuetype [mscorlib]System.ConsoleKeyInfo [mscorlib]System.Console::ReadKey()
  IL_0011:  pop
  IL_0012:  ret
} // end of method Program::Main

Wow. The IL is exactly the same. So both the VB.NET and C# code compile down to functionally identical assemblies.

And that's one of the most important characteristics of .NET: it lets you write code in any language you want (as long as someone has written a compiler for it), and run it on any platform you want (as long as there's a CLR for it).

I worked with Visual BASIC from versions 1 to 6, and then did one project in VB.NET before switching to C# in 2002. You really would need to pay me a lot of money to go back to it. I believe C# is more expressive, more concise, and more able to reflect my intentions than VB.NET.

But there is nothing wrong with VB.NET. If you want to use BASIC, enjoy. With the .NET ecosystem, it's up to you.

A is for Assembly

Welcome to the Daily Parker's 2018 Blogging A-to-Z challenge!

Blogging A to ZWe're starting today with a fundamental concept in Microsoft .NET software development: the Assembly.

Microsoft defines the assembly as "a .dll or .exe file that can contain a collection of APIs that can be called by apps or other assemblies." In other words, an assembly is the basic unit of delivering .NET software to the rest of the world. An assembly "fully describe[s] and contain[s] .NET programs."

When you compile .NET source code, the compiler creates one or more of these files, each of with contains an Intermediate Language (IL) representation of your original code. You can then distribute the .dll or .exe files to any computer that has the correct version of the .NET Common Language Runtime (CLR) installed on it.

I've created a Visual Studio solution for this challenge. Today we're looking just at one small piece of it, which looks like this:

using System;

// ReSharper disable CheckNamespace
namespace InnerDrive.DailyParkerAtoZ.HelloWorld
{
	internal static class Program
	{
		// ReSharper disable once UnusedParameter.Local
		private static void Main(string[] args)
		{
			Console.WriteLine("Hello, World!");
			Console.ReadKey();
		}
	}
}

If you're new to .NET, don't worry about all the pieces. This two-line program compiles into an assembly called HelloWorld.exe, which internally looks like this:

.method private hidebysig static void  Main(string[] args) cil managed
{
  .entrypoint
  // Code size       19 (0x13)
  .maxstack  8
  IL_0000:  nop
  IL_0001:  ldstr      "Hello, World!"
  IL_0006:  call       void [mscorlib]System.Console::WriteLine(string)
  IL_000b:  nop
  IL_000c:  call       valuetype [mscorlib]System.ConsoleKeyInfo [mscorlib]System.Console::ReadKey()
  IL_0011:  pop
  IL_0012:  ret
} // end of method Program::Main

Again—we're not going to get into a lot here. Suffice to say, that IL above is what actually lives in the assembly, and what the CLR will execute when you run the program. The assembly also contains a manifest, describing what it contains, and some metadata about its version, author, and whatever else the programming team has added to the assembly info file.

As with all of the topics for this year's A-to-Z challenge, I'm only scratching the surface. There is a ton more to read online and in some solid books on the market. The best information about assemblies I've found is in Jeffrey Richter's CLR via C#.

Note: the Visual Studio Solution for this challenge requires Visual Studio 2017 and the .NET Framework v4.7. ReSharper is also recommended.

Tuesday link round-up

Late afternoon on Tuesday, with so much to do before the end of the week, I can only hope actually to read these articles that have passed through my inbox today:

And now for something completely different tonight: Improv and Arias. Which is why I wonder whether I'll actually get to read all of the articles I just posted about.

1.5 Gs

As of just a few moments ago, I passed 1.5 billion seconds old.

Yes, this is a thing most people don't really think about, but as someone who works in software, this actually has some significance—and another Y2K problem that will occur just a few months before I get to 2.0 Gigaseconds (Gs) in 2038.

The problem is a thing called the Unix epoch. Computers can only count as high as they have bits to count. Unix computers, which include Macs and most of the infrastructure of the Internet, count time in seconds from 1 January 1970 00:00 UTC, which was (at the moment I'm typing this) 1,521,383,994 seconds ago.

Everyone knows computers can count to awesomely huge numbers. But you need to give them enough bits to do that. Unix time is measured by a 32-bit number, which can count up to 232-1, or 4,294,967,295 (in binary, a 32-item string of 1s), which is enough seconds to count just over 136 years.

But you sometimes want to measure things that happened in the past, so Unix time takes the first bit of the 32-bit number and makes it a sign. If the first bit is 0, the time is in the present. If it's 1, the time is the number of seconds before the beginning of the epoch. So this cuts the measurable period in half, to 68 years. Specifically, Unix time rolls over at 3:14:08 on 19 January 2038.

The fix is simply to use a bigger number. Today, 64-bit numbers are no big deal, and they give you 263-1 (9,223,372,036,854,775,807) seconds to work with in either direction. That's roughly 292 billion years, which is sufficient to measure most human-scale activities.

So, knowing all this, and knowing that I was born in the first year of the Unix epoch, it wasn't difficult to figure out my "epoch" birth moment at 9:12 CDT this morning.

But there's a catch. As I mentioned, computers count by 2s, not by 10s, so this entire post is a lie. I'm not 1.5 Gs old; I'm just over 1,500,000,000 seconds old. 1.5 x 230 (i.e., 1.5 giga anything) is 1,610,612,736, so I won't be 1.5 Gs old until Unix moment 1,631,995,056, which will be 18 September 2021 at 19:57:36 UTC.

So check back in three and a half years. I'm sure I'll have another post about this nonsense then.

(For those of you keeping score at home, I was 1.0 Gs old on 13 September 2004 at 20:09:04 CDT, during a lull in blogging. Else I'm sure I would have mentioned this then.)

Long weekend; just catching up

Saturday and Sunday, the Apollo Chorus sang Verdi's "Requiem" three times in its entirety (one dress rehearsal, two performances), not including going back over specific passages before Sunday's performance to clean up some bits. So I'm a little tired.

Here are some of the things I haven't had time to read yet:

Other stuff is going on, which I'll report when I have confirmation.

Function following forms

Designer Josh Gee spent two years trying to put Boston city government forms online:

Getting city workers to accept online submissions rather than traditional paper ones is the bulk of this work. On average, it took me about 30 minutes to make a digital form and five weeks to meet with, earn the trust of, and get buy-in from the employees who would use it. Even if they were excited, the nitty gritty details took a lot of back and forth.

While I avoided a bunch of process change, there were some takeaways that I think are useful for anyone working to move government forms online:

  • There is huge demand to move forms online — I had expected to drag departments online kicking and screaming. Instead, the majority of departments were eager to move things online and thrilled to have a partner with the technical knowledge, mandate, and tools to do that.
  • Flexibility about form structure and questions — I initially thought there would be a strong demand for submissions that look exactly like current paper forms. That hasn’t been the case. In all but one or two cases, I was not only able to move forms online, but also suggest changes that made forms shorter, more clear, and more accessible.
  • Excited about future change — Early on I began to notice a pattern. A few weeks after I moved a form online, some departments would to reach back out and ask for tools to help them manage digital submission, “This has been absolutely amazing. It would be great if I could approve it and then send it to Steve for his signature”. I thought a lot about the phrase salami slicing. If I tried to change everything about the way these departments worked right off the bat, they would have resisted every step of the way. Moving just a part of their workflow online made them eager to go completely digital.

This is close to home as my company is right now engaged in an effort to do this sort of thing for the U.S. Military Enrollment Processing Command. It's not easy.

The plan

Today I plan to take Parker on a decent walk before it gets cold and starts snowing. I'm also working on a couple of minor updates to Weather Now, including looking into creating an API against which I can write a React/Relay front-end.

Also I have a lot of reading to catch up on, some of which I may write about.

In other words: a quiet Saturday at home.

Why I hate the suburbs

I spent over 3 hours in my car today in principal because there were no public transit options to my remote, suburban destination. That, plus all-day meetings, means that instead of outlining what I'm planning for the weekend—I'll do that tomorrow—I'm just going to line up some articles I want to read:

I now have to pack. Parker will be unhappy with this.

Happy 2018, UTC!

It's now just past what computer people call "2018-01-01T00:00:00" (or, in more human-readable form, "2018-01-01 00:00:00 +00:00").

Some of you will remember that 2017 was exactly 1 day and 1 second shorter than 2016, owing to the leap second added a year ago at 2017-12-31T23:59:60.

Even thought 2017 was that much shorter than 2016, it seemed so much worse. But that's literally behind us now (or at least in the 13/24ths of the world on GMT or ahead of it). Here's looking to 2018 to be just a tiny bit better.

Happy new year!