Friday, December 21, 2007

Top Ten, 8 of 10

When we last left our hero, we were looking at ten ways to get screwed by the "C" programming language. Today's entry is Easily changed block scope.

if ( ... )
foo();
else
bar();

When adding a line of code to either the if or the else clause, one needs to add braces. If you add to the else clause this way:

if ( ... )
foo();
else
i++;
bar();

the i++ statement is in the else, but bar() gets called no matter what. One needs to add braces.

if ( ... ) {
foo();
} else {
i++;
bar();
}

OK, so the braces aren't needed for the if clause here. But since this is the way that the language works, and since braces can be placed anywhere, and since braces do not slow down the compiled code, or add anything to the code size, why not put them everywhere? It reduces the chance of error, increases consistency, and makes editing easier.

There are C programmers who skip braces for one-line if statements:

if (...) doit();
if (...) doit2();

but not

if (...) { doit(); }
if (...) { doit2(); }

despite C's terse block structure. I'm not one of them. I don't use one line if statements.

Thursday, December 20, 2007

Top Ten 7

When we last left our hero, we were looking at ten ways to get screwed by the "C" programming language. Today's entry is Indefinite order of evaluation.

Be sure to also read the supplementary dialog on the subject. I personally come down mostly on the side of the Respondents, and by extension, with Dennis Ritchie's original language design decisions. This may reflect the fact that i came to C after writing a boat load of assembly language for various processors. And yet, there is still wiggle room for yet another opinion. Here it is.

I'd have expected that the order of evaluation in function arguments would be left to right, no if's, and's, or butt's. Here's why. Function arguments are separated by commas. In C, the comma operator is the left to right evaluation order guaranteed syntax. So, in the context of function arguments, the comma operator is effectively overloaded to mean that the order is not specified. That's inconsistent at best.

A related complaint of mine with the C language is the overloading of the while keyword. In my opinion, it shouldn't have been used for both do{...}while(); and while(){...} loops. My objection has to do with reading a program in a free form language that has been badly indented. It isn't a strong objection.

While it would be nice to have a tool, ideally in the compiler, that warns that undefined behavior may take place, it's hard to imagine how such a tool could work, even slowly. Certainly, a simple example like:

foo(i++, i++);

would be easy to catch. But trivial examples like this are also pretty easy to catch by eye. It's the more complicated examples that would be worth having a tool.

And yet, in the last half million lines of C code i've written, and in the millions of lines of C code i've examined, this yawning chasm waiting for someone to fall into continues to wait. Uninitialized variables are much more common yawning chasms. Languages that provide initial values for variables even if they aren't explicitly set have fewer bugs. C is the fusion powered chain saw without safety gourds. It will happily let you hack your own legs off. At the same time, it has historically set the gold standard for speed.

Wednesday, December 19, 2007

Top Ten 6

When we last left our hero, we were looking at ten ways to get screwed by the "C" programming language. Today's entry is Unpredictable struct construction.

There are several issues that lead to the exact way that C structs are laid out in memory by any C compiler. Yet, it should be noted that, as a systems language, C was explicitly designed to allow one to set a structure pointer to map to a hardware device so that bits in that device can be manipulated. The first issue is that computer designers have two choices on how to lay out the bytes of a larger integer. These are Big Endian and little endian.

#include

int
main(int argc, char *argv[])
{
long abcd = 0x01020304;
char *ord = (char *)&abcd;

printf("%0x:%0x:%0x:%0x\n",
ord[0], ord[1], ord[2], ord[3]);
return 0;
}

Hex notation is used to set the long integer abcd. Each two characters of hex specifies eight bits, or one byte in memory. On an x86, Arm, and other machines, this prints "4:3:2:1". The character pointer points to increasing addresses. The first byte printed is 4, which is the value of the least significant byte in the long. This is little endian, meaning that the least significant byte goes into the smallest address. On a Sparc, 68000, and other machines, this program prints "1:2:3:4". That means that these machines are big endian. So if one creates a struct with a long integer (perhaps of type int32), writes it on an Arm, and reads it on a Sparc, the Sparc will read the bytes backwards from what the Arm wrote. The Sparc would have to reverse the bytes in each word read in order to be able to get the original meaning.

Some file formats allow either big endian or little endian storage. For example, the TIFF image format allows either. The file format has an indicator for which format was used. The reader program then knows if byte reversing is needed. The reason TIFF allows either is that very often, the same computer is used to read and write the image. If the computer uses the native format, then no reversing needs to be done. This is more efficient.

There are other problems with structures. One is word alignment. Consider this structure:

struct foo {
char first;
long second;
}

Most 32 bit machines read 4 byte long integers faster if they are aligned on an address that is divisible evenly by 4. That's because that's how the memory is physically addressed. If the word isn't aligned, then two words of memory need to be read in order to get the desired word of memory. Some computers take this farther. If an attempt to read a word is not word aligned, the computer generates a fault, and processing is halted. That way, all working programs are faster. On such machines, the C compiler makes sure that structures are always maximally aligned. Padding bytes are added to make sure any long integers are word aligned. So, the above structure is actually represented this way:

struct foo {
char first;
char pad[3];
long second;
}

The pad bytes are not directly usable by the program. They are, in fact,
not named. Now, if one doesn't really care how the bytes are ordered, one can always put the word aligned parts first:

struct foo {
int32 second;
char first;
}

This ensures that no padding will happen. Then if the structure is written to a file, and read from a file on another machine, one can be pretty sure that everything will at least start in the right places. One still has to deal with the Big Endian or little endian issue.

In the old days, pretty much ending with the Vax, binary floating point representations were nearly as varied as the number of different machines available. One solution to this problem was to write them out as text. For example, "-123.456e-21" specifies a very small negative number. The reading program would parse that with sscanf(3) or something, and the result would be a native format number. This parsing can be slow, but having the program work is important. However, since about when the 68000 and x86 got floating point, IEEE754 floating point has been adopted by nearly all chip makers. This format is uniform at the binary level across essentially all platforms today. There is no byte ordering problem. In fact, in 1990, a company that made databases optimized to work on CDROMs used IEEE754 floating point binary as the interoperable format. It supported a large number of computer platforms, and none of these platforms had to do anything special to make it work, unlike for long integers.

Could these issues byte you? Sure. The C language has many, many nods to optimization that turn out to be issues one must think about all the time. If you don't like to think, consider learning idioms to get specific tasks done, and simply reuse them as needed. That makes C a copy and paste language for you. However, if thinking isn't something that turns you on, perhaps programming isn't the right profession for you. Or, consider that C is a poor language choice.

Tuesday, December 18, 2007

Top Ten 5

When we last left our hero, we were looking at ten ways to get screwed by the "C" programming language. Today's entry is Phantom returned values. The example is:

Suppose you write this

int foo (a) {
if (a) {
return 1;
}
} /* sometimes no value is returned */

Generally speaking, C compilers, and C runtimes either can't or don't
tell you there is anything wrong. What actually happens depends on the
particular C compiler and what trash happened to be left lying around
wherever the caller is going to look for the returned value. Depending
on how unlucky you are, the program may even appear to work for a while.

Now, imagine the havoc that can ensue if "foo" was thought to return a pointer!

Rubbish. The bit about random stuff getting returned is true enough. But C compilers can mostly tell that sometimes a value isn't returned from a function that is declared returning a value. While gcc does not report any warning by default, the -Wall option yields the following warning:

return.c: In function 'foo':
return.c:5: warning: control reaches end of non-void function

That is, if a function is declared void, it doesn't have to return a value, and therefore it can drop off the end. In C, one can't return a value by dropping off the end. One must use a return statement; So, for example

int bar(a) {
return 1;
while (1) {
;
}
}

This does not produce a warning. If you remove the return statement, it still does not produce a warning, because the compiler knows that the while statement is an infinite loop. If you remove the while statement but leave the return, the compiler again knows that the end of the function is not reached. The return statement itself causes a return, and returns a value. If you change the return statement to just return;, the compiler warns this way:

return.c: In function 'bar':
return.c:2: warning: 'return' with no value, in function returning non-void

All this to say that compilation with -Wall can catch errors that might otherwise consume your time. If you fail to use the option, shame on you. If you use the option and ignore the results, shame on you. In the early days, these warnings were available from a utility called lint, which knew the language but did not actually produce an executable. Presumably, the thought was that burdening the compiler with warning reporting was too much for each iteration. But the result was that people didn't check for errors as often.

Yet, there is a common case where you have a function that is declared to return a value, but you often know that the return value isn't used. Worse, you sometimes know that this function won't need it's arguments, but it is declared with them anyway.

#include <stdio.h>

int main(int argc, char *argv[])
{
printf("Hello, World.\n");
}
produces these warnings
hello.c:4: warning: return type defaults to 'int'
hello.c: In function 'main':
hello.c:6: warning: control reaches end of non-void function

Now, main returns a value to the environment. That is, the parent process, often the shell, gets the return value, and may use it for loop control, error reporting or whatever. But sometimes you know that it won't be used. And the same is true for the arguments. The above program does not need to know the command line arguments. If you write main without a return value, the compiler will complain at you.

hello.c:2: warning: return type of 'main' is not 'int'

What to do? Best advice is to return a value anyway.

In the original top ten, the return statement was written this way:

return(1);

While this works, and does what is expected, the parenthesis are not needed. The return statement is a statement, not a function, and does not need parenthesis around the argument(s). I like a style where functions have the parenthesis right next to their name(s), return statements have none, and loops such as for (...) and while (...) have a space between the keyword and the parenthesis. Visually, the reader can learn to recognize functions as functions without thinking about them too much. This convention and is never enforced by compilers, so consistency, the hobgoblin of little minds, must be enforced by self discipline. As a matter of style, i'd like to think that i'm not nearly arrogant enough to think i've got no hobgoblins. And besides, it's not for me to judge if my mind is little or not. It's a job for God, if she cares.

I am, however, qualified to judge C compilers. The bar for C compilers is gcc. If the compiler you supply isn't as good as gcc in some way, you have little excuse. The gcc compiler is available for free in source form. You can download the source, find out how it behaves, examine the source code, and you can update your compiler with that knowledge. If your product isn't as good as one available for free, eventually your very smart customers will use the superior free one. That doesn't mean, for example, that gcc won't optimize some corner case slightly better than yours once in a while. gcc is, after all, very good. The bar is quite high for C compilers.

Monday, December 17, 2007

Top Ten 4

When we last left our hero, we were looking at ten ways to get screwed by the "C" programming language. Today's entry is Mismatched header files. The example is:

Suppose foo.h contains:
struct foo { BOOL a};

file F1.c contains
#define BOOL char
#include "foo.h"

file F2.c contains
#define BOOL int
#include "foo.h"

now, F1. and F2 disagree about the fundamental attributes of
structure "foo". If they talk to each other, You Lose!

I've seen this sort of error in released commercial software. How embarrassing. Often, a library is shipped in binary form, with header files that describe the structures and calls used. For no apparent reason, these libraries often have huge numbers of header files. And the above sort of problem can happen.

My own tendency is to have a single header file that describes everything. The single header file can't be self inconsistent, as the compiler would show such errors right away. Besides, it's just easier. It's easier for the library developer, as there is less to cross check. It's easier for the library user, as there's just one header file to include.

And yet, i've written a set of four libraries that are somewhat intertwined. A low level linked list library stands on it's own. A library with routines that handle errors needs the linked list library. A library that deals with comma separated files uses both the error library and the linked list library. A library that provides interfaces needed to write CGI programs, and also access to various databases also uses all three others. As each library has non-overlapping focus, the headers are not in any danger of providing conflicting definitions. But there are still four header files. For one thing, you might want to use just the linked list library alone. I've done this.

Friday, December 14, 2007

Top Ten #3

When we last left our hero, we were looking at ten ways to get screwed by the "C" programming language. Today's entry is 3 Unhygienic macros. The example is:

#define assign(a,b) a=(char)b
assign(x,y>>8)
which becomes
x=(char)y>>8 /* probably not what you want */

If the macro were instead written this way:

#define CHAR_ASSIGN(a,b) (a)=(char)(b)
CHAR_ASSIGN(x,y>>8)
it becomes
(x)=(char)(y>>8)

which might be what was desired. One wouldn't call it assign since it has a known side effect, which is the cast to the type char. One generally uses ALL UPPER CASE for macros, since that is the convention that nearly everyone uses in C for macros.

One might wonder why the original isn't what you want. In case it isn't obvious, here it is. If you cast an integer that is bigger than a byte to a one byte char, then shift it right 8 bits, you always get zero or -1. That's because a shift right of eight bits is the size of a char. Negative numbers shift right, but copy the sign bit (which is 1), positive numbers shift in zero bits. So at the end, you get 0 or -1.

Of course, since macros are text expansions, one tries to pass the simplest expressions to them. Some macros use their arguments more than once. So if you pass such macros an argument that has side effects, you could end up with the effects taking place more than once. For example,

#define DOUBLEIT(a) ((a)+(a))
DOUBLEIT(it++)
becomes
(it++)+(it++)

which increments the variable it twice, even though it looks like it happens just once. And, who knows what the return value is?

Thursday, December 13, 2007

Top ten #2

When we last left our hero, we were looking at ten ways to get screwed by the "C" programming language. Today's entry is 2 Accidental assignment/Accidental Booleans. The example is:

int main(int argc, char *argv[])
{
int a, b, c;

if(a=b) c; /* a always equals b, but c will be executed if b!=0 */
return 0;
}

to which i say that gcc -Wall says this:

two.c: In function 'main':
two.c:5: warning: suggest parentheses around assignment used as truth value
two.c:5: warning: statement with no effect

Two warnings! The first suggests something like:

if((a=b) != 0) c;

This is what is implied by the code, though probably not desired by the coder. The second warning, statement with no effect means that the evaluation of the integer 'c' does not produce any machine code. There's no usable side effect. Nothing. But hey, this is just a contrived example, and is beside the point.

As early as Borland's Turbo C 2.0 for DOS (now available for free), we had compilers that would warn about this. And, it has saved people much time and effort. These days, gcc's -Wall option is good practice.

I happen to like the feature. I use this sort of thing all the time:

if ((p = getenv("DOCUMENT_ROOT")) != NULL) {

which says copy the return from getenv() to the pointer p, and then check if it is NULL, which is an error to handle. The parentheses are there just as gcc suggests. Without them you get the return of getenv compared to NULL, and that boolean assigned to p. Probably not what you would want.

The main problem over the years with gcc -Wall is that your distribution's header files change out from under you, and old code that compiled clean periodically needs to be cleaned up again, even though nothing is wrong, and nothing has changed. Worse, at times, the distribution header files make it impossible to get through a compile without noise. Why is that bad? If you are expecting warnings, you start ignoring them. No news is good news.

Wednesday, December 12, 2007

Top ten

The top ten ways to get screwed by the C language has 18 entries. I was a bit surprised that entries weren't numbered starting at zero. Entry 15 (which you might note is more than ten) talks about using an array past it's end.

Today, let's start with number one.

#1 Non-terminated comment, "accidentally" terminated by some subsequent comment, with the code in between swallowed.

a=b; /* this is a bug
c=d; /* c=d will never happen */

In the eighties, i wrote a small filter (in C, of course) that can do two things. First, it can show you all the comments in a C program. Second, it can remove all the comments in a C program. This basically solves the debugging of this problem. By looking at all the comments, it becomes obvious, as in the previous example, that some code has been commented out. Since about that time, i've used '#ifdef' to effectively comment out code. In the early days of C, however, before the evil C preprocessor was invented, one would use another idiom:

if (0) {
c=d;
}

The optimizer would notice that the code couldn't be reached and left it out. But then, my comment filter wouldn't show it, right?

Where is this filter now? Well, i've planned releasing it, but it just hasn't happened. I might have published it here, but my home machine is down right now. I might finish repairs tonight.

This thing with comments is, of course, by design. The most memorable time that i was bitten by it was back in the 80x24 terminal days. Someone who worked for me submitted non-working code, but had run out of time to debug it. It turned out that this person used a comment block, where each line of the block had an open and close comment bit. However, the last line of the block's closing comment had a space between the '*' and the '/', so didn't close the comment. Why wasn't it obvious? The terminal didn't wrap the line (which was 81 characters long), it wrote all characters starting with the 80th in the last column. So, the space went there, and a millisecond later (9600 BAUD) the slash went there. At that point, it looked like '*/'. That may have been when i wrote the filter. But i may already have had it. Single stepping in the debugger showed that some code was missing.

Thursday, November 29, 2007

Gilgamesh

In the 80's, i read Robert Silverberg's Gilgamesh the King. This is a novelization of the epic poem. I loved it. To be honest, i hadn't been turned on very much by Silverberg's other works, though my friends like him. Pick up a copy. Amazon is showing it for 2 cents. What's with that? You must have to pay shipping, at least. It's a must-read.

Author Stephen Mitchell has written a modern verse english version of the epic tale of Gilgamesh, entitled Gilgamesh. Kind of an odd thing. I'm pretty sure that i downloaded it from Librivox, but there is no sign of it there now. Perhaps it was mistakenly published there. It is available from LearnOutLoud for about $20. The book is narrated by George Guidall, who has the perfect voice for this work, and provides a competent reading of the book and Stephen's analysis and notes. It is published on four CDs, but takes a bit over three hours.

The book itself is on two CDs. When i reached the end of the book, it was announced that the rest of it was commentary by the author. I thought i'd skip it. I thought of the main book as very short. Silverberg's novel is, well, a full length novel. That should be some eight hours of audio. Yet it was about two. Though i liked it, i thought that the commentary would completely bore me. I know the story. What is he likely to add to it?

And yet, there it was. After a few days, i stuffed the first hour onto my iPod, for consumption on the way to work. If it was terrible, i could always skip to my next podcast. So, it starts out a bit slow, picking apart the details of the story. But instead of basically repeating what was already in the story, he provides insight on why the original author used the structure that was used, why the original author picked the perspective that was used, what the inuendo means and doesn't mean.

OK, so here's where i'm coming from. If you launch an application, say Microsoft Word. But, really, any application will do. Turn on context sensitive help, and point at something, and read what it says. In MS Word, it's under the Help menu, and it reads "What's This". Point it at the icon that vaguely looks like a floppy. It will say something like Saves the active file with it's current file name, location, and file format. Nothing wrong with that, right? Except that it says nothing about why you might want to do such a thing. For Save that is perhaps, not a big deal. But for many more complicated functions, it's everything, and the online help is useless. But Stephen Mitchell's commentary on Gilgamesh covers exactly the why do we care? ideas. It's really very good. It's written by someone who has really thought about it.

Ok, so the book is short, and there's an equal length commentary. It some ways, it's a Reader's Digest or Cliff's Notes version of the epic. Not that i read either Reader's Digest or Cliff's Notes. But in other ways, the work is an attempt to create a translation that captures the spirit of the original. Not easy to do for a work in a dead language. Even if one stands in the footsteps of giants.

(If I have not seen further, it is because I stand in the footsteps of giants. - a wonderful misquote of Newton.)

Wednesday, November 28, 2007

Extracts from Adam’s Diary

I recently listened to Extracts from Adam’s Diary, a Mark Twain piece read on Librivox, and available for free download. The work is short. There are five chapters, the longest is about six minutes. It's a good quality recording, and read competently. Twain has sharp wit, and this somewhat masks the points he also manages to insert into this short story. If Genesis read this way, more people would understand it.

I particularly liked it, partly because it happens to be a bit of Twain i'd never read before. I've read alot of Twain, so this is becoming more rare. I have read Twain's Letters from Earth, which also has a Biblical bent. But where Twain didn't release Letters, probably because he wasn't satisfied with it, he did release Extracts. Letters starts out sharper, but soon runs out of good material, and drifts from focus. Extracts maintains focus and reaches a conclusion.

It's funny. It's a very consumable sound bite. What are you waiting for?

Tuesday, November 27, 2007

Reading books

Ars has an article about how reading ebooks is not like reading books. The article tries to make the point that somehow paper books are better. Or at least, something is lost going to a non-paper form. I'd say we've gotten to the point where this is moot. In particular, there's an image of a book in the article. Guess what? I read the article in a browser. I could have done this on a portable browser. I get the full artwork. It's also a special case.

I have a 2002 vintage Visor Platinum. If fits in my shirt pocket. It has a monochrome LCD with backlight. It works well in full sunlight, and pitch dark. There is a twilight where the backlight isn't strong enough which is pretty awful. This situation doesn't come up often. It runs on twin AAA batteries, which last, with modern rechargables from the grocery store, about 20 hours per charge. I can carry spares, for longer life. The device life in not limited by batteries. It has 8 MB memory (RAM/file store), enough for several books. The Bible is 1.44 MB compressed. It cost $110 when new. I bought two of them. One loads new books on it via USB or serial.

Until recently, i used it to read books, using the freeware weasel reader. It reads Palm doc books, and also it's own zlib compressed text format. It's own format has bookmarks that can be prebuilt for chapters, etc. There is a utility that will create this format from Gutenberg books, for example. It has two usable fonts - small and large bold. It allows bookmarking and annotating. It remembers where you were in a book. So you can always annotate using some other Palm application, like creating a memo.

I never annotated real books - postit notes hadn't been invented, and i never got into that habit. I don't write in books. But with electronic books, i'll spot an error, and put together a 'diff file' and send it to Gutenberg. My changes tend to make it into the archive, and i'm encouraged to continue doing this. Electronic books are interactive for me in a seriously real way.

There are only a few books i've read more than once. The Harry Potter series, and The Lord of the Rings, for example. But also, from Gutenberg, Reddy Fox. I've read this one maybe five times, out loud. It's incredibly hard to proof read, and i found errors even in the 5th reading (using a text will all my previous corrections applied). Most errors will go unnoticed, but i hope i've helped improve the quality of the work.

I read about 50 books a year. I read about 35, and listen to another 15. It takes a long time to get through 1,000 books. Having alot of books makes sense primarily for reference.

The Visor is an excellent book reader for me. The battery life is long. The device is highly portable. It's main drawbacks are that it is no longer sold - so it can't be replaced, the digitizer is fragile, and it will eventually break, it was basically incapable of showing pictures, it was limited to plain text - no bold, italics, etc.

Now, I have a a Nokia 770. It was about $150 new (sort of closeout). It is the same physical size as the Palm. It has an internal (but replacable) rechargable battery which lasts about 5 hours. That's enough for a commute. One loads data on it via USB or WiFi. The screen is high resolution color. I have 2 GB of file store, enough for a small library. FBReader is available for it, which can read plain text, html (but it is NOT a web browser, in particular, it doesn't seem to let you follow links, so books should be one huge file). FBReader can read compressed files. But with 2 GB of space, this isn't much of an issue. FBReader lets me pick colors for text and background, as well as font and size, so i can customize the experience to the lighting conditions. I read alot in the dark. HTML books, such as A Christmas Carol on Gutenberg, have a few images, and FBReader displays them extraordinarily well on the 770. FBReader also lets you flip between books easily.

The 770 also has a real web browser (Opera) which allows me to read some web based books better. It also allows me to surf the web, read web comics, etc.

The 770 also has a PDF reader. I don't like PDF for online books. I much prefer a format where i can increase (or decrease) the font size, and have the machine rewrap the text to match the screen size. The PDF format is not very flexible. PDF's which have been formatted for two columns on 8.5x11 paper work better than those with one wide chunk of text. But on the 770, i'll make it work if the content is worth it.

With several book readers available, i find that i'm reading several books at a time. Two or three in FBReader, three or four in a web browser, and typically one or two in PDF.

The 770 can play music. I don't generally listen while reading. If it turns out that playing music consumes the reader's batteries, one could use an appropriate dedicated mp3 player. My iPod lasts about 18 hours on a charge. Other mp3 players use AAA batteries, and a pocketful will last weeks of continuous use.

I don't currently commute to work hands free. When i did, it was about an hour each way. I have used a laptop during the commute, and four hours endurance was fine. I could (but didn't) recharge at work.

Tuesday, November 13, 2007

Sony book reader

Ars Technica has a review of the Sony PRS-505 electronic book reader. Very strange. $300. It can read books, and play audio (badly). No downloadable software. So if this isn't exactly what you need, then that's it. Move on.

The screen is grey scale. 8 greys. It has alot of dots - 800x600. The screen does not consume power when displaying - just when you turn pages. But, it takes 2 seconds to turn a page. If there's no backlight, then it's game over for me, however. What i really like to do is read in the dark. The batteries last a long time, unless you play audio. There's a memory stick - and, yes, it's Sony's proprietary format. It syncs to Windows computers only. I don't run Windows.

I've read tons of books on my 2002 vintage Palm OS Visor Platinum. It's 8 MB RAM holds tons of books. At one point, i had the entire Bible, and several other books on it. There are at least half a dozen free book readers (software) to pick from for it. One of the book readers was pretty slow turning pages. Not as slow as two seconds, just not very fast. Fortunately, other readers are quicker. The Visor Platinum has an LCD screen, which works fine in bright sunlight, and has a backlight for reading in the dark. If you aren't using the backlight, the batteries last for days. And, since the batteries are just AAA's, you can always bring spares, or stop in at 7/11.

OK, so my new Nokia 770's color screen is nicer. Even very tiny text is very sharp. However, the rechargable battery only lasts 4 or 5 hours. It handles text and PDF's and web pages. FBReader is totally awesome on the Nokia. It's better than the best of the Palm readers. For reading in the dark, i like to set the page to black, and the text to a dark red. Very nice. No screaming white light around the edges - just red text. The Nokia was $150 (on sale). The770 uses an MMC memory card. Can't get it at your local store, but it is an industry standard, available on the net.

Tuesday, November 06, 2007

Ipod Vs My Musix

For various reasons, i have two mp3 players. I've had both units for more than a year. In fact, both units are no longer sold as new. Even though they both have excellent sound, I really only use one of them. Try to guess which one it is after the descriptions below.

One is the original Apple iPod Shuffle. It looks like a white pack of gum with a rounded rectangle look. It has a button in a ring. The button is the play/stop button. The ring has forward a track and (hold it down) fast forward, back a track and (hold it down) rewind, volume up and volume down. There's a blinking light indicating it's on, etc. I mostly ignore it. On the back, it has a three position switch which gives you power off, sequential play and shuffle mode. There's a button which lets you check the state of the internal battery. The light shows green, amber or red.

The unit has a USB connection. You mount it on some computer, add tracks, and delete tracks. You need software which knows how to update the database on the device, otherwise, the device won't play it. I use gnupod, since other software for the iPod doesn't really work for Linux. This software works on the command line, has awful syntax, but this can be fixed with aliases and such in your shell's startup file. The key is that it works. I could say that again, but you'd get bored. You can store things on it that aren't music, for example to copy things from one place to another. Inside, there is half a GB of flash. That's enough for 12 to 20 hours of content, depending on encoding, quality, etc. While you're connected, the battery charges. I don't think about the battery unless i'm going on a long trip. It usually works. But for long trips, the limit is 18 hours of use on a full charge. I haven't tested this lately.

If you pause the unit, it will eventually turn itself off. When you turn it on, it sometimes remembers where you were in a track, and sometimes it skips to the beginning of the track. Sometimes it forgets the track, and skips to the "first track". This is the same as the first track your computer reports is on the device. Sometimes, the software records that you deleted a track, but the track isn't actually deleted. It takes up space, but isn't accessible. It can be hard to figure out which track it is, or even notice that it has happened. The tracks are always renamed with a "1_" prefix added. Sometimes, part of the file names are removed. It might have something to do with the DOS FAT 32 filesystem, and name length limitations or name mangling. Hey, blame it on Micros~1.

The other unit was on sale at Radio Shack, and is called My Musix. It is black, rounded everywhere, slightly fatter than the Shuffle, but otherwise comparable in size. On the front is a fairly large dot matrix display, which tells you what you're doing. There is a big play/stop button. There is a forward track and reverse track rocker, and if you hold them, you get fast forward/reverse. There is a volume up and volume down rocker. There is a record button. There is device lock slider switch. Lock it, and other controls will not respond. Handy for preventing error.

Turn the unit on by pressing the Play button. Turn it off by pressing (and holding) the Play button. Play by pressing Play, right? Well, that depends on what mode you're in. Mostly, i press the Record button first, which puts it into a mode menu. Modes let you change folders, each which might have different content, like a book in one, and space music in another, and podcasts in a third. Have as many as you like. Another is Play mode, where you can opt for sequential or random play. Another mode is Delete. You can delete tracks from the interface. Another mode is Repeat - including none, one track, one folder. Another mode is FM Radio. You can tune in FM stations. You can even record FM. Play the FM later, or download it to your main computer. Another mode is Record. You can record ambient audio. The sound is recorded with 8 bit samples at 8 KHz. Not very high quality. There are two levels of menu. The settings menu has a mode for setting the screen backlight. You can use a red backlight - which is good for astronomy, as it doesn't ruin your night vision.

The unit has a USB connection. You mount it on some computer, add tracks, and delete tracks. No special software. When the device turns on, it figures out what it has, and lets you play it. You can store things on it that aren't music, for example to copy things from one place to another. It ignores things it doesn't understand. Inside, there is one GB of flash. That's enough for 24 to 60 hours of content. That's enough that you can stuff content in a folder for reference. It uses a AAA battery. I use rechargeable batteries. It gets about 8 hours on a charge, but you can bring more batteries with you, so you get infinite duration with minimal preplanning. If you don't preplan, there's always 7/11. And if your rechargeable battery dies a final death, you can always pick up more at the grocery store. The design of the battery cover door suggests that you'll misplace it sometime. So far, i've been careful, and though i've lost it twice, i've also quickly found it again. It's a nuisance when you have to pull off the road to fish under the seat. Probably should have pulled over to change the battery. Think safety first.

If you pause the unit, it will eventually turn itself off. When you turn it on, it sometimes remembers where you were in a track, but always skips to the beginning of the track. Sometimes it forgets the track, folder and everything. You usually get to the first track in a random folder. Well, it's random to me. It even forgets the track when you actually turn it off gracefully, sometimes. It sometimes suffers from the Micros~1 problem. However, it doesn't, in general, rename files. Though long folder names sometimes get renamed to eight characters. This summer, i loaded Lord of the Rings audio book tracks on it, and the unit was bricked. I called customer support, and got software that let me reflash it. The new software fixed the unusual characters in the filenames can brick the unit problem, and cleaned up some display bugs too. I now have the software, and can use it any time to unbrick the unit. Since the unit behaves so much better, i'm actually glad i had to reflash it. In fact, if they had a registration system, and could, for example, send you email when new operating software was available, it would be worth signing up for spam. In any case, the customer support rocked. It's hard to remember when i've dealt with good customer support before.

Note that both units have their faults. The Apple Shuffle needed to keep the form factor, fix rewind so that it can hack into the end of the previous track, fix it so that it remembers where it is in a track when it is turned off, and remove the "off" position, letting it toggle between sequential and shuffle mode only. The form factor is fine - it didn't need to be made smaller. I'd offer it in multiple colors, not just white. Of course, then i'd buy the unpopular polka dot version at discount.

The My Musix needs to have a single menu, not two nested menus. It needs to remember where it was when turned off. If it's going to record, it needs to be high quality 16 bit sound with at least 22 KHz samples, preferably CD rate samples. Mono is OK. The battery cover design needs fixing. The display shows the current track. But if the track title doesn't fit in the display, it scrolls. It starts scrolling instantly, which doesn't give you time to consume the first few characters. Just a couple second pause before scrolling would fix this. It should be offered in multiple colors, not just black. Of course, then i'd buy the unpopular polka dot version at discount.

OK, so which one do i use? Simple interface, half storage? Or complicated interface, replaceable batteries? The answer is that i nearly never use the My Musix. But one day the battery in the Shuffle will die, and i'll switch to the My Musix, and use it for twenty years. And i'll likely pine for the good old days when life was simple.

Friday, November 02, 2007

speling

I've used a spell checker ever since they became available. For me that was about 1980, on a DecSystem 20. That's when i first got access to a spell checker that could quickly offer good guesses as to what i probably intended. These spell checkers improved my spelling skill dramatically. At first, my essays were filled with errors. But, the spell checker would catch them, and usually offer the right word. I'd study how the word was really supposed to be spelled, and after being corrected twenty or thirty times, i'd start getting it right the first time. Spell checkers improved my typing as well.

One must still proofread. That's because spell checkers will not save you form every mistake.

Monday, October 29, 2007

Nokia 770 backup

The ssh package for the Nokia comes with sftp for file transfer. I thought to do backups by creating a big tar file and using sftp over WiFi to get a copy to my desktop. This is not an ideal solution, as one needs to create the whole archive before starting a transfer. That means you have to have enough space to create the archive. Now, the archive could take less than half of your space because tar doesn't waste any space in the last blocks of files, and the entire archive could be compressed.

But the ssh package also comes with scp. The -r option recurses directory trees, and the -p option preserves file modes. The -q option eliminates the messages about what file it's working on, and how far it has gotten, and how long it thinks it will take to finish. I've no idea how long it really takes. Just plug it into AC, connect to the backup machine via WiFi, start the scp, and call it a night.

On the backup machine, running linux, i use my mcmp program to detect files that are, in fact, identical to other files brought over from, for example, previous backups. It can create hard links from one to another, so the backup files only take filesystem space for files that actually changed. For me, that's not alot. Mostly what i do is copy books and audio to it. Reading these things does not cause the files to change. I really should release mcmp. It's fast and reliable.

The desktop computer is also backed up. I plug an external USB hard disk in, and tell it to make a copy. When it's done, i dismount the backup drive and power it down. That way a power spike can't take out both the primary and backup. Single files can be restored, if needed.

Do you have a backup plan for your computer(s)?

Wednesday, October 10, 2007

Word as reader

Have i mentioned how terrible MS Word is as a document reader? Today? A couple starting caveats. First, i'm using Microsoft Word 2002 sp3. Second, this isn't just Microsoft bashing, as fun as that is. Many modern word processors suck as document reader applications. And yet, if someone writes a document in a proprietary format like Word, you expect that somewhere down the line, someone will use Word to read the document. It might be the author, for proof reading. It might be the prospective employer, who needs to read your resume (or is it CV now - latin seems to be making a comeback. Is that because of Harry Potter?).

So, what is it, exactly that is so awful? Is it Page Mode vs. Normal? Is it the zoom level, and having to zoom in when dealing with print resolution graphics, but then zooming out to cope with the text? Is it dealing with objects that don't fit on the screen?

No. It's the idea that the page down and page up buttons change your insertion point and any screen movement is incidental. So if you use the scroll bar, and then forget and use page down, it typically jumps back up.

I'd rant some more, it's so much fun, but there's little more to say.

Tuesday, October 09, 2007

Best Practices

A colleague had this collection of PDF documents on various aspects of building software. One, entitled High-level Best Practices in Software Configuration Management talks about how to get the most out of your source control system. It was written at Perforce Software, Inc., and though it tries to be general in nature, it reflects their product, which i've never used. It was written in 1998, and was obsolete at that time.

The paper talks about branching and code freezes and codelines and workspaces and builds and the processes that an organization must have to do to cope with a serious problem. Merges.

So, in the old days, one used a source control system, like SCCS or RCS, and of course others. In these systems, the source code cycle steps through these points:

  • check out the code with an exclusive edit lock
  • edit the code, and test it
  • check the code back in.


This works OK, as long as you have only one developer, and one workstation for that developer. But the moment this isn't true, then at some point in development, one developer will have a file locked that another developer wants to edit. So, either the second developer waits for the lock to free - perhaps by doing something else, or the second developer asks the first to add her changes too, and check them in. Or perhaps even more creative solutions are explored.

But often, the second developer is working on a version of the code that will be released at some other time than the first developer is working on. Same application, just code that won't be released for an extra month. Then, each developer needs their own set. The usual way to do this is for at least one developer to create a branch, and work there. Now, when the first developer finishes his release, the code is checked in.

The second developer has a new problem. The code she started with isn't the code that's now in production. Changes made for the first release aren't in the code set for the second release. These changes need to be merged into the new set. The key point in this Best Practices paper is Get the right person to do the merge. It's important to do this step right because it is error prone, tedious, and did i mention error prone? I've done this work. I've even been the right person for the job. I volunteered for this work because I wanted it to be done right. It wasn't that my efforts would be lost if it wasn't done right. It was that the team's progress could be lost if it wasn't done right. And no one else on the team seemed to understand the problem. And yet, the correct right person to do the merge isn't a person.

As early as 1993, i was using CVS. Here, the computer performs the merges. It's fast and reliable. If the merge detects a conflict, it notates this in the code and allows the developer to fix it. But because of this simple change, the whole source code control flow changes. Now it's like this:

  • check out the code
  • edit the code, and test it
  • update the local copy with changes from the repository
  • check the code back in (but leave this new copy out).


Now, the only time that the source code is locked is for a few seconds while the code is being checked back in. Since the code is nearly never locked, any developer can edit whatever they want whenever they want to. The merge happens during the update.

A merge conflict happens when there is a change to the same line of code. When that happens, the two versions of the code are marked in the updated file. The developer edits the file, figures out if one version, the other, or some new code is needed to resolve the conflict.

One might think that since updates are performed all the time, that developers would be constantly fixing merge conflicts. This is not the case. Generally, if two developers change the same line of code, it usually means that they are working on the same problem. If they aren't working on the same problem, there are seldom any conflicts.

So, in a multiple release system, branching is still needed. But the merging process can be automated. And it's long past time that we should need to do this by hand.

So, this is old news, right? Why rehash it now? Because vendors still sell obsolete software. For example, i work for a company now that uses Serena's Dimensions product. This product, based on PVCS, is an old style edit-with-lock and manual-merge system. It has some nifty work flow stuff layered on top, but the hard problems are still hard, and color the way any work is done. To wit, our current release is projected to be at least two weeks late because it was noticed too late that a merge would have to be made. (Sorry, Serena's site seems to be dehanced for Firefox with a pointless entry gate screen. Entry gates went out in about 1995.).

To be fair, i have no idea how Serena thinks that an issue like: Development processes involve time-consuming and unreliable manual hand-offs can be solved with their product. As near as i can tell, if you want overlapping releases, you are stuck with manual merge.

So who bought into this system? Why aren't we using CVS or SVN, which are free? Did they consult with senior developers? I wasn't consulted. These are Best Practices. It must be some definition of Best that i've not heard.

Thursday, October 04, 2007

Alcohol

Very funny xkcd.com cartoon.

Since alcohol slows reflexes, one would think that it would slow thinking in general. As programming requires some of most intense thinking anywhere, one would expect that imbibing would categorically be a bad thing. Yet, there are two pieces of evidence that i'm aware of that contradict this.

I worked with a guy who preferred working from home, over a slow modem, to working in the office. At home, he could work with a six pack of beer (brand not specified). He said it was less painful. Let's say he sees a bug. When sober, his reaction was Damn! Another bug. But after a beer or so, his was reaction was Ha ha ha, another bug, and he'd get right to it. So, apparently, psychology can be an important factor for programming.

But i also did an experiment, mostly by accident. In the mid 80's, i was at this keg party of mostly geeks. Thing about keg parties is that i'm a really cheap drunk. It just doesn't take much to get a buzz. So, i can't really count cups (they were plastic, and so can't be properly called glasses) after one. I've no idea how much i had. Enough so the Universe spun, but not enough to bring me to the ground. Anyway, this guy, whose name i don't recall, was talking to me, and i mentioned this graphing package that i'd just written. We had forty something devices capable of plotting results, and they were all different. Our plotting packages only knew about three or four of these each, so you got your output on one of those. If you wanted output on a better one, you'd start from scratch using another package. So, i invented an intermediate format, and a series of filters that could translate to and from it. This guy said he had access to a new laser printer, and had the manual for it. How long would it take to create a filter? I'd have said a couple hours. You know, just take a filter that looks like it, and modify it. He wanted to do it right away.

Now my judgement was nearly entirely impaired, so despite the time, maybe two in the morning, we started right away. We staggered to my office, and started hacking at it. I don't remember the details. But when i got in to work later in the morning, the resulting filter still worked. Further, the code wasn't bad. Over time, the bugs will eventually show themselves. But no maintenance was needed for this filter. Ever.

Windows ME really was pretty awful. But it seems more likely that alcohol was involved in the decision to release it rather than in development.

Friday, September 28, 2007

Psion Organiser II

Psion Organiser II, Nokia 770, Handspring Visor PlatinumIn 1987, i picked up two Psion II Organisers. They were really hot when they came out! They look pretty much the same as each other, but one has 32 KB RAM, and the other has 8 KB RAM. RAM is used for file storage too, but internal RAM has some special features. There are two slots for expansion memory for file storage. They come in two flavors. RAM with a watch battery for persistence. And EEPROM. The Psion can write to it. But you can't rewrite. This can be overcome by marking records for deletion. When it becomes full, copy the stuff somewhere else, erase the pack, then copy stuff back to it. This is how you get the space back from deleted files. They also came with an RS-232 serial cable, and you can copy files to a host, like DOS, back and forth. This is how backups are done. The 8 KB system has some limitations. It can't use my 32 KB RAM pack. You must have 4 KB RAM free to use the serial port. They also can make beeping sounds. Pitch and duration are controllable, so i wrote a music program. Sounds like one of those birthday cards that you open and it makes noise. But, you can write your own tunes, with multiple octaves, repeats, etc. The display is two lines of 16 characters. There are user defined characters, giving one almost pixel by pixel control.

The serial port on my 32 KB Psion died. That meant it could no longer be backed up, and i stopped using it for anything more than a calculator. The 8 KB Psion is still nearly pristine. Well, except that dates past 1999 don't work in the calendar. Feh. Bloody Y2K.

These machines have the Hitachi 6303x processor. This chip can access 64 KB of memory. Half of this is ROM, more or less. They run at about 2 MHz. The 9 volt battery lasts a couple months of normal use.

The applications include a calculator, calendar (appointments), notes, file transfer (with special software on the other side) and remote login (can act like a terminal). The units are also programmable. On board, there is a language called OPL. OPL is something like BASIC, but without line numbers, and with block structure. Even after years of not seeing this language, i can read and write these programs without reference to the manuals. There's something to be said for a language that easy. There is also a cross assembler that runs under DOS. I studied the manuals, but never actually wrote anything for it.

So, a comment suggested that my new Nokia 770 is probably much faster. No need to guess. I have benchmark results for both, using benchmarks i started using in 1982. Here are some numbers:

Matrix Multiply
Timex780Machine & Language
0.03083143.2100Athlon 1913 MHz C
12.12007.9900Athlon 1913 MHz Perl 5.8.8
5.159618.7800Nokia 770 C
238.47000.4060Nokia 770 Perl
9.820014.1300Compaq Aero 486sx/25 C
25920.00000.0037PocketC Visor Platinum
612000.00000.0001Psion Organiser IIXP OPL


Sieve
Timex780Machine & Language
0.0602310.2300Athlon 1913 MHz C
19.5707.0900Athlon 1913 MHz Perl
0.896154.7900Nokia 770 C
181.7500.3800Nokia 770 Perl 5.8
278.2140.4490Compaq Aero 486sx/25 C
90744.1330.0014Compaq Aero 486sx/25 Perl*
22135.0000.0063Palm Platinum Cbasic
57000.0000.0020Psion Organiser II OPL


Unfortunately, i don't have Perl benchmark runs for the Aero. I probably hadn't written them yet. I have extrapolated a Sieve Aero time using Athlon times. This doesn't work for the Matrix Multiply, as the 486sx/25 didn't have floating point hardware. But to be fair, i didn't use Perl on it much. No, i really don't have eight significant digits of timing information. I'm just trying to get the decimal points to line up. Benchmarks like this often have a ten percent variance between runs anyway. The Vax 780 was benchmarked in the early 1980's, and was considered by many to be the 1 MIPS (Million Instruction per Second) machine. But since some machines must execute more or fewer instructions to get something done, a more fair comparison is to test some workload.

There are two workloads here. The Matrix Multiply does lots of floating point multiplies and adds, with two dimensional array indexing. The Sieve performs integer comparisons and single dimensional array indexing. Since neither the Palm nor the Psion have floating point hardware, both of these machines perform relatively better at the Sieve than the Matrix Multiply. The Psion CPU doesn't have integer multiply, handy for two dimensional arrays.

But yes. The new Nokia is 300 times faster for the Sieve, and 2,500 times faster for the Matrix Multiply. And yet. Both of these benchmarks are in languages that compile to a virtual machine code, which is then interpreted. Any semi-modern desktop using a real compiler should be 20 million times faster than the Psion. When i get a benchmark run in C on the Nokia (easy enough), i expect a factor of 300 to 400 improvement over the Perl version. And if i manage to shoehorn the matrix multiply into the Nokia's DSP (Digital Signal Processor - a super computer's vector processor of sorts) (and more difficult to accomplish) then the sky's the limit. That's how the Nokia does sound and video, after all. Or, i might run into the short vector lengths (20). To be fair, i haven't attempted this in the Athlon's funky on-chip FPUs or GPU.

A brief note about Perl. Yes, there's a huge performance hit compared with C. But even on the 486sx/25, many applications would be fine. For example, many web based programs would still finish in much under a second, and you'd think it fast. And for some machines, it's not a factor of 300, it's a factor of 1,000. And it's still OK. This still bothers me. Perl 5.8 (and later, i suppose) comes with a Perl compiler, which improves things by a factor of five. I don't see it used much. Another odd thing is how little code i have hanging around written in Perl at home. For the past six years or so, it's been my primary language. But when i want to write something at home, it's nearly always in C.

Thursday, September 27, 2007

Nokia 770

The digitizer on my 2002 vintage Handspring Visor Palm Pilot is crapping out on me. It's functional, but every few seconds, i have to recalibrate the digitizer. Sometimes, it messes up during the recalibration, and it can take five minutes to get through it. It often helps to try twisting the whole device this way and that to get it to work. So, i want to replace it.

Some history. Before getting the Visor, i had a 3.5 pound subnotebook. It could do everything my desktop could do, but with less memory and disk. Further, it could communicate with my desktop fast enough for backups and data sharing. But, it was more expensive than my desktop. When it died, i did without for a number of years. Eventually, i picked up the Visor, and though i lost much of what i'd used the subnotebook for, i started using the Visor for new things that i now depend upon.

One way to replace the Visor is to pick up a cheap Palm. The cheapest $100 Palms have three or four times as much memory, are faster, and have color. What's not to like? Just backup the Visor, restore to a new device, and get on with life. But i'm the type of guy who shops carefully for bananas. This is much more important and expensive than bananas.

The deep dive investigation should take into account the Three P's. Portability, Performance, and Price. If it isn't portable, you won't use it. If it can't do what you want, you won't use it. If you can't afford it, don't buy it. But otherwise, price can be optimized. You might get performance at the sacrifice of portability. That would be the desktop.

I did a wider search for bliss, and discovered that the Nokia 770 (in process of being replaced by the newer, bigger Nokia 800) has been heavily discounted, and appears in my price range. It has some new capability. It combines the functionality of my old subnotebook, but with the portability and applications of an organizer. It runs Linux, like my desktop, though that isn't evident from the casual look. Linux is under the hood, and i can get at it. It has the power and resources to do things even a new Palm won't do. Here's a comparison:

FeatureCompaq AeroVisorNokia 770
Date1995-19992002-20072007+
Display640x480 grey160x160 b/w800x480 color
Data entrykeyboard, mousestylusstylus *
Carry inbrief casepocketpocket
Performance10 MIPS5 MIPS100 MIPS
CommunicationsCable 22 KB/secUSB 100 KB/secUSB or Wireless 1 MB/sec
ProgrammableYesNot reallyYes
Apps usednote pad, planetarium, book reader, calculator, Web GUI-DB backed app development, web browsingnote pad, planetarium, book reader, calculator, calendar, sketch, contacts, music apps.Video clips, photo album,note pad, planetarium, book reader, PDF reader, calculator, calendar, sketch, contacts, music apps, Web GUI-DB backed app development, web browsing
User file store70 MB4 MB192+ MB
Cost$600$110$150 (sale)


While the 770 has a stylus, it also has remote login, as did the subnotebook. But that means that one can use the desktop's keyboard. Further, a wireless bluetooth (or WiFi?) keyboard can be purchased. A USB keyboard might be usable, but the 770 does not have a powered USB port, so a powered hub would be needed. To make it portable, you'd need a battery powered powered USB hub. A bluetooth keyboard would be cheaper and easier. I'll try remote login from the desk first.

In the last months of my Visor, i experimented with various languages for it. Chipmunk Basic is free, but is a crippled version of BASIC, and is slow. Lispme is free, implements a variant of scheme, nearly produces executables that you can hand out (you need to give them the whole environment), the environment is fragile, and the speed isn't very good. There is a free C cross platform compiler that runs under Linux, but what i'm looking for is something i can goof around with on the device. Really, the Visor is too slow to be acceptable for an interpreter. Further, the Visor's one-app-at-a-time execution environment means that the user has to wait for any computation to take place. My best guess is that Quartus Forth is the best language. It's not free, but it produces small standalone executables. Too late.

By contrast, the Nokia 770 has a Perl environment installed when you buy it. That means i can hand out a perl script, and that's it. It will just work. And tiny perl scripts can do alot. There's also a shell, so shell scripts are also possible out of the box. While there is a native C compiler - word on the street says it runs out of resources for non-trivial applications. There is a cross platform C compiler. Python and Ruby can be installed. Further, the processor performance is high enough that a language that does not compile to the native iron, like Perl, Ruby and Python, is acceptable for a large number of applications. Further, since it really multitasks, the user can start a computation, and do something else while waiting.

It's been about a week. So, for example, i haven't tracked down and installed a calendar application. So far, the search has only turned up an app that can't turn on the machine and beep. On the other hand, i haven't even gotten a wireless router set up. How have i gotten anything? Well, one of my neighbors, has an open wireless setup, and cable. Thanks, whoever you are. I've been real happy with it so far. But the real test is how i'll like it over the next few weeks.

The latest news is that it appears that there is a Palm OS emulation application. It may be possible to download my favorite Palm OS apps, and run them on the Nokia.

Tuesday, September 25, 2007

My job is so secret

So, imagine that you have a development cycle where a two line can take six months to make it into production, assuming diligent developers and savy management. By the time the fix gets into place, everyone involved has forgotten what needed fixing. Devlopers have been working in a devlopment environment, where the fix has been around for ages. Testers have to be reminded that it isn't a new bug, and, by the way, the fix is in the pipeline. End users have forgotten that they needed it fixed.

My job is so secret that not even i know what i'm doing.

Wednesday, September 19, 2007

Pirate talk

Pirate flagIt was Talk Like A Pirate Day today. Arrg, mateys, and you can lay to that!

Thursday, September 13, 2007

Dark Energy

I was at the store the other day, and noticed that they now sell disk drives that can hold a terabyte of data. Well, of course they hold more data. The whole Universe is expanding!

Tuesday, September 11, 2007

Queues

The third Rule of Acquisition clearly states, "Never pay more for an Acquisition than you have to", ST:DS9, The Maquis, Part II.

So, large American, Car companies want to save money while conducting their business. Business is complex, and computers can help keep track of things, etc., so they use them. Over time, the Information Technology department becomes rather large and complicated in and of itself, so they look for ways to save money there, too. All this is natural.

One of the issues with computers is that they themselves are rather complex, and require considerable training to use, program and maintain. Good database administrators, programmers, systems administrators, etc., are highly skilled people and therefore are expensive. In general, companies are drawn to organize these people by skill, putting like people into like groups. For example, there's a systems administration group, or a database administration group. A programmer, attempting to write or maintain some application needs to communicate with such a group to make use of such expertise, but also to get access to relevant systems to make needed changes.

As the organization grows, these groups change from technology enablers, to technology gate keepers. They become responsible for systems security, enforcing corporate policies, and so on. To reduce costs, these groups are reduced in size until each person is fully loaded with work. The result is that when a programmer needs to make changes in a system, their request enters a queue, and weeks go by before any action is taken. When mistakes are made, more weeks go by before corrective action is taken. This can be true even for the most trivial of changes, where the programmer had appropriate expertise to make changes, but did not have authority.

And, an honest analysis shows that the body count isn't reduced. It turns out that both the requesting programmers, and the servicing administrators are required to fill out paperwork, perform extra unneeded steps, and real productivity is minimal. The customer has to wait longer, and everyone ends up with more overhead than actual productive work. Far from ensuring quality, mediocrity is enforced. This is not the fault of the individuals.

This tendency to crowd people together by type has long been recognized in industry. The resulting stovepipes generate communications difficulties and pointless overhead. It is not unusual for the overhead to exceed an average of twenty or thirty times the amount of real work, as measured in hours. Worse, much of the overhead is geared to measure progress. Data from these logs are used by managers to show that the system is becoming more efficient, even as latencies grow ever longer. These statistics are, of course, wrong, not just misleading.

Clearly, it's no fun to work in an environment that is mired in bureaucracy. But how does one fix the system? The key is to point out just how terrible the system has become for the end customer. Further, one needs to point out how the head count has grown while productivity has decreased. The evidence clearly shows that small integrated teams, with all the expertise in a tighter nit group are considerably more effective. One needs systems administration, database administration, developers, business liaisons all in one place. If single individuals have competence in more than one area, they are that much more effective. That suggests that small groups control their hardware, systems software, and applications software. Small groups should develop their own standards for backup, source control, coding style and database naming conventions, application deployment, and so on.

Sure, the larger company should have policies, but the development group should be able to treat these as suggestions. If they decide to deviate from company policy, they should be able to do so without a waiver of any kind. Then, the policies will reflect business needs, rather than reflect blind guesses.

What about external requirements, like SOX? These are business requirements, like any other. Let the development group handle them. If they require reporting, then reports become policy or part of the automation, as makes sense. The key is that things should make sense.

Wednesday, August 29, 2007

Thumb loading

I talked about thumb drives a while back. And, i'm at it again, downloading huge amounts of stuff and tossing it onto thumb drives.

Not only does it take awhile to fill a 2 GB kingston, but it also sends the load average through the roof. It's typical to take an otherwise unloaded system from a load of zero to a load of 5. And, it stays there for the duration. What's with that? The CPU is 99.7% idle. So, it's not like parallel ports where the CPU needs to do something every few bytes transfered. What are the other 4 tasks waiting to run? And despite the low CPU load, responsiveness during copies to the USB thumb devices is sluggish and jumpy.

This is under Linux.

Anyone have any idea why? Is it different under Windows? Mac? OS/X?

Tuesday, August 28, 2007

Canoe trip

Ducks on a log

It's late in the season, but the canoe trip experience has finally taken place. We're not talking about a shakeout run to make sure everything works. We're also not talking about days on the water, or some other big deal. But, a trip with passengers. It's taken nearly a month to get it together.

Since we're, at heart, city folk, the trip takes place in a city. The Huron River runs through Ann Arbor, MI. Since it was otherwise quiet and peaceful, we brought along a couple ten year olds to provide continuous noise. The ducks were unable to compete with this noise, and so, stayed quiet themselves.

Gorgeous day. This is, unfortunately, the best picture taken all day. It had to be modified to look even this good. Mallards, i think.

Monday, August 27, 2007

Internal Discipline

bug eyesWhen we last left our hero the large organization was overrun by high latency task groups that were effectively obstacles to progress.

Another feature of large organizations, and by large i mean organizations with more than one person, is externally applied discipline. The problem to be solved is How does one motivate the employee to produce good work?. For the software developer, it's the wrong question.

One of the common management approaches to this problem is characterized by the carrot and stick paradigm. The idea was that to get a horse to pull the buggy, one had a carrot and a stick. The carrot was a reward for good behavior. The stick was punishment for bad behavior. Now, modern management has no experience with horses, or they'd know that the stick was not for punishment. The carrot was suspended by a string from the stick. But that isn't the modern interpretation.

Any parent will note that a promised reward is a much better motivator than punishment for children. In fact, punishment doesn't work very well, and not at all over the long haul.

But managers generally don't think that they have anything to offer an employee (which is false). They also don't think that they can get away with much in the way of punishment (which is also false). So, despite the above very common and widely talked about concept, it often plays almost no actual role in obtaining quality work.

What managers really know how to do is the paper trail. To get the developer to use source control, have a manager sign off that code is in the system. To get the developer to adhere to database standards, have a database administrator approve any database usage or changes. To get the developer to add user level help pages, have someone who only handles installing help pages on the system review the text and install it. To make sure that the customer is satisfied, have the customer sign off on the project before it is placed on the server. Each of these processes adds delays to the project, but do they ensure quality?

No. It turns out that the database administrator doesn't know anything about the application code. So even a simple query that uses only indexed keys might in fact be issued to the database millions of times. Only the developer would know that. The help text manager doesn't really know the application, and can easily miss omissions and outright errors in the text. Worse, help text usually concentrates on the details of how a function works, but never gives the end user any idea why one might want to use the function. That takes context. The customer signs off on the application, but does so at application launch. It may be a month before the customer is familiar enough with the product to be able to really evaluate it.

External discipline is inefficient and ineffective. The solution is to empower the developer to do the right thing. First, the developer should be aware of the kinds of quality that the customer wants. It may be consistency, repeatability, discoverability, ease of use, etc. Second, for those quality issues that only a developer could understand, review should be made by another developer. Code reviews have the side benefit of disseminating knowledge. Even the most senior developers learn something. Involve the database administrators early in the process, not late. The DBA should suggest good ways to do things up front, not stall a project nearing completion. To do that, the developer and the DBA need to work together. For best possible speed, they should be a single person. The customer should be able to give feedback at any time, not just before the launch.

Thursday, August 23, 2007

Empowerment

bug eyesLarge organizations have a problem. It's a hard problem to solve. That is, how do you organize the division of labor when you have a large number of people? It's not a new problem. Sun Tzu's The Art of War covers it. The general was asked, "How large an army can you command?". His answer was "the larger the better". Old problem but solved.

People tend to learn new skills fairly slowly, so it is commonly thought that no one knows how to do everything. In any case, the large organization tends to discover, often by luck, that a person knows how to do some specific task, and then uses them for that one task exclusively. As the organization gets larger, groups of people form to perform specific tasks, and the organization tends to treat these the same as individuals, performing one task forever.

The large organization then takes these task groups and establishes processes that let the groups get things done together. When there is a complaint that the process isn't written down, it tends to get written, and becomes less flexible. When problems of quality arise, and let's face it, humans make mistakes, the reaction is to manage quality by requiring that a high level manager signs off on actions. But these people don't know how to do everything, so they don't know how to judge quality. They become a source of latency for projects, with no added value. Management thinks in terms of paper trails, and requires paper documents for everything.

The ebb and flow of work to do means that some task groups feel overloaded from time to time. They set up often elaborate queues where tasks are submitted, and 'customers' are given a minimum wait to get things done. For example, a database administration group may require a minimum of a week for any task - even if the task requires no analysis, no research, no diagnosis, just a simple command sent to the software. Often, these groups require that there is no face to face or even phone contact, and miscommunications are frequent, requiring resubmission of the task, with attendant latency.

So, let's say you're a developer, and the project is to project a web based application. Checking your source into the source tree requires sign off from the source code control group. Placing the application on the server requires sign off from the hardware and web server software groups. The database administrators need to sign off on the way the database is used, even if there are no new tables. The help text for your application is managed by yet another group. The application took a week to write, but takes an additional six weeks to deploy, if you're lucky.

How can this be fixed? Instead of attempting to manage quality by instituting sign offs by management enforced by restricted access to systems, the trend should be to manage quality by automated paper trails, with automated back-out systems for failure mitigation. The emphasis is on automation to reduce latency. Empower the developer to get things done by giving them the tools needed to get the entire job done. Trust that the developer will attempt to do the right thing, but don't be afraid of failure. Fear of failure causes paralysis.

There are a complicated set of issues. For brevity, this is just one of them.

Monday, August 20, 2007

Troll

Kirk vs Janeway

COBOL vs Java

Miata vs Jeep

Spaceship One vs Shuttle

Meede vs Orion

Discuss

Monday, August 06, 2007

Tom Swift

On the way home from Bible Camp, my ten year old son and i listened to a 4 hour book downloaded from Librivox. Tom Swift and the Visitor From Planet X, written by Victor Appleton II. It went over well. There was a cliff hanger every chapter, except the last. This could be serialized on radio easily. 20 Chapters, so they must have only been ten or fifteen minutes each. That's short enough for nearly any attention span.

The reader, Mark Nelson is very good. No memorable mistakes. Maybe there aren't any. He does it with a 1950's style, with gusto, WoWee! But should you want to read it yourself, the full text is available on Gutenberg.

It's science fiction, with an action/adventure feel, but i had difficulty placing just when it might have been written. It has a 1950's style, but seemed to have references to more modern inventions. Fortunately, one doesn't have to guess, since Wikipedia knows it was written in 1961. And, it knows who Victor Appleton II is, and what a busy guy Tom really is. He had something like a hundred such adventures. And those are just the ones that have been written up so far.

The story has it all. Hot sex - well - there was a quick kiss on the cheek. I wasn't paying attention. It might have been Tom's sister. And, it has violence. Well, there was an earthquake, and some property damage. Space aliens, including the Visitor from Planet X. I was hoping the space alien would have something to teach us about global warming or world peace. Not a word. The one named villain turned out to be a spy working for the good guys. In retrospect, it's hard to believe there were 19 cliff hangers.

Monday, July 30, 2007

Canoe

So, the canoe and bike rack was last set up on the previous car. It's a fairly fancy Yakima setup. There are these adapters, and the rack has been on four different cars now. But it had never been on the Saturn, so it was an hour getting it there. There probably is a clip designed for the Saturn, but i was able to make an existing set work. At least it's secure. Well, i didn't do the acid test - drive on the highway. I would have, but the on ramp to i75 south was closed. The primary test wasn't the drive, it was the canoe.

So, the canoe works. You see, there are paddles, and life jackets. A water bottle. Some binoculars. Can't go anywhere without binoculars. And... and that's it. So really, most of the test was getting the canoe onto a car.

With the rack on the car, the next step is to find the key, and unlock the lock which holds the chain. This is easy, since the lock was unlocked just a couple months ago. Except, that the key can't be found anywhere. After a half hour fruitless search, it is decided that one link of the chain can be cut, freeing the lock, and by the way, the canoe. This takes an hour. It's a very good chain (now slightly shorter).

I'd have never designed a canoe rack that has the canoe upright. I mean, when it rains, it fills with water, right? If too much water gets in there, then what do you do? The car could be overloaded, or the canoe might be too heavy to remove. Bail it? So far, though, it just hasn't been a problem. And for some reason, i've never thought to load up the canoe with everything in sight. One can put alot of stuff into a 17 foot canoe.

One nice thing about the rack is that in addition to the canoe, two bicycles can go up there. And, they go up without rubbing against anything. Nothing worse than a bike rack that damages the bikes. Or the car.

The test run for the canoe involves putting it into the water, and paddling around for a couple hours. Elizabeth Park has a nice parking lot, a little channel that goes out to the Detroit River. From there, one gets to deal with wind and waves. My trip took me to the bridge, which swung open to let a large boat through - always exciting.

And, i made it back alive. Mostly. Nothing damaged that can't be cured
with a little wine and a long bath in the hot tub.

Monday, July 23, 2007

Harry Potter Book 7 - no spoilers

I've now read half of the book. The non-spoiler review so far: i like it.
There's not much to say beyond that without giving something away.
So, I'll stop.

Please don't post your spoiler here.
For example, don't flip to the last page and tell me the last word.
Even if that word turns out to be "the" (which is unlikely. I'm not sure
i could construct a sentence that ends with the word "the").

I'm not reading the web until i've finished the book. It could be
a few days. Unfortunately, i have to eat and sleep, too.

Monday, July 02, 2007

iPhone Diet

The new buzz is that one of the women at work got a new iPhone over the weekend. She's been goofing with it, and showing it off, pretty much as one might expect. In fact, lunch got moved back quite a bit. Not just for her, but for many of us.

I'm calling it the iPhone Diet. It can affect those around you, too. And, they don't get to decide if they want to participate. I didn't get to decide, and i don't even want a phone. My angle is more what user interfaces could be adopted for the Palm Pilot.

This isn't a balanced diet. You could get serious malnutrition from it, if prolonged. Fortunately, like most diets, it isn't expected to last.

See also, the Relative Diet, and Zeno's Diet.

Wednesday, June 27, 2007

Bad Weather

We have a thunderstorm, right now, raging outside. I'm glad i closed my windows.

If you closed your windows, how did you post to your blog?

I mean, the windows in my car.

Monday, June 18, 2007

Coolest new app

Well, it's new to me.

sudo apt-get install dict
sudo apt-get install dictd
sudo apt-get install dict-web1913

This gives you a 1913 English dictionary with definitions, from a local dictionary. That means it continues to work even if you are off line. From the command line, this example gives you a definition:

dict synopsis

Friday, June 08, 2007

How fast is your thumb?

My beloved 128 MB Jump drive is lost. Stolen, actually. One of the things that i really liked about it was that the cap really sealed the stuff inside. It survived being left in a pocket and going through the wash. Twice.

My 512 MB Firefly was lost, so i had no thumb drive at all for several weeks. Well, not exactly. My iPod Shuffle is 512 MB (discontinued), and often has 100 MB free, and can be used to transfer arbitrary files too. But, I finally broke down and went to a store. My Jump drive cost something like $35 way back when, and being somewhat short on cash, i wasn't going to spend more than $20. I'd just have to get a small one. In a bin by checkout at MicroCenter, were 2 GB Kingston drives for $15.95. With tax, that's $16.90. So much for settling for a small one.

The Firefly turned up shortly thereafter. Both drives are in use. And something odd turned up. I downloaded interesting audio books from LibriVox, which turned out to be several gigabytes. The Kingston drive seemed to take quite a while to fill compared to the Firefly. Yet, transfer speed at home was much better.

At first, i thought that perhaps the computer at work had an older USB 1.0 interface. That's absurd, though. It's nearly three years younger than my computer at home. And, why would the FireFly be so much quicker? Well, the firefly is a quarter of the size, so maybe that's it. There's no way to get to the bottom of this without some measurements.

It turns out that i'm only writing data at work, and only reading it at home. And the Kingston is nearly nine times slower writing than reading. The Kingston is about 20% faster at reading than the Firefly. But the Firefly is only half as fast writing than reading. So, the Firefly is four times faster writing than the Kingston. And, since it's a quarter the size, filling it takes a 16th of the time.

OK, so the speed of the device is not listed anywhere. Would it be a deal breaker? No. It's quick enough, cheap, and has large tracks of land.

Wednesday, May 30, 2007

Carded

They card you for Nyquil. Perhaps it still has alcohol.

I would not give anyone like this any strange ideas. For example, when crossing the border into Canada (or on the way back to the US), and they ask, Do you have any drugs?, it's probably not such a good idea to say, "Damn. I left them at home. I knew I forgot something!

When crossing the border, and they ask, Do you have any fire arms? It's probably not a good idea to reply, I can get you anything you want.

But let me know when you're going. I'd like to go along and see if they strip search you.

Friday, May 25, 2007

Make Mine a Double

Radio Lab on WNYC is available as a podcast. Season three starts out with a discussion of the Placebo Effect. For example, the doctor tells you that this light blue pill will make you better, and it does. Only, there are no active ingredients in the pill. You got better, at least to some extent, because you thought you'd get better.

Now, you might think that a doctor who gave you a sham pill is a quack. He doesn't know what he's doing. He's selling moon shine - that is, something you could have gotten without him. But the deal is, you actually got better.

And even the medical doctors who have real training, and are backed up with real medicine, put on their white coat and talk to their patients in a way that convinces them that they'll get better.

Now i listened to this show while sick. I stayed home from work. I'm not paid when i stay home, so when i stay home, it means i'm on death's door. And when i only feel terrible, i go back to work. After all, if i'd stay home, i'd feel terrible, and if i go to work, i'll feel terrible. I may as well get paid for it.

I'm not a good salesman. I've mentioned the bagel club. For me, giving out bagels and donuts for free is a hard sell. And, i'm very skeptical. That means the story has to be really good for me to have any chance of believing it. Double blind clinical trials are the gold standard. Pray to Jesus just isn't going to do it. I can't be hypnotized because, well, i don't believe in hypnotism.

So, imagine that i'm cheap. I don't want to go to the doctor for antibiotics. I have an idea how long it will take me to get over things, and, for the most part, antibiotics don't make me well any quicker. But, i do want to get something that will help. What do i do?

Here are my cures for the common cold. Drink lots of water. In fact, drink a gallon of water a day. You can drink more water if it's room temperature. A gallon is alot. It's probably twice as much as you think it is. So keep a full glass in front of you all day. Drink it. Linus Pauling advocated high doses of vitamin C. I've not found that mega dose pills help at all. Nor an orange. But a pink grapefruit seems to help. Eat the whole thing, without sugar. Avoid sugar altogether when ill. Get lots of sleep. As much as you can. Use any trick you can to get to sleep. Lie perfectly still and try not to think. Turn on a boring radio program and close your eyes. Whatever works. Shower. Brush your teeth. Sore throat? Gargle with aspirin. Gargle with salt. Gargle with mouthwash. Gargle with chloraseptic.

I'm not sure that any of these things work. That is, i don't know that they have any external helping ability. But they feel like they work. And, if you do them all day long, you should at least get the placebo effect on and off all day long. And the placebo effect is real. It's real chemicals that your body releases. And there are no side effects. And, in double blind clinical trials, it really works.

It's mind over matter, after all.

Steve Martin said it best: "I'd like one of those new double strength placeboes, please".

Monday, May 21, 2007

Astounding Science Fiction

I'm just a bit behind in my podcast listening queue. At the beginning of April, Escapepod ran their 100th episode. They run short science fiction. The stories are typically under and hour. Episode 100 went slightly more than an hour. However, it was written by the legendary Isaac Asimov. Nightfall. And, it's good story. Many say it's the best ever written. It's not really dated. You might expect that from a story written in 1941. What i will say is this: If you're only going to listen to one science fiction short story, this is the one to try. And, you might just get hooked. Fortunately, the archives go back to the beginning.