PKLITE supplement 9: Min/max alloc. part 4

This is Part 4 of my series on how PKLITE and the MINALLOC/MAXALLOC fields. Start with Part 1. For a list of all my PKLITE posts, see the first post. This will be a short update, to cover the formulas used by some PKLITE beta versions. Also, I'll summarize which versions use which formulas. Summary …

PKLITE supplement 8: Min/max alloc. part 3

This is Part 3 of my series on how PKLITE and the MINALLOC/MAXALLOC fields. Start with Part 1. For a list of all my PKLITE posts, see the first post. AX, continued In Part 2, I noted that, for v1.14 and higher, the "AX" field is sometimes increased by 80 (decimal, measured in 16-byte units) …

The boy born on Tuesday puzzle

Every now and then, some variation of this puzzle makes its rounds on the internet: You're given that a person named Mary has (exactly) two children. She tells you that one of them is a boy born on a Tuesday. What is your assessment of the probability that Mary's other child is a girl? It's …

The universe is very, very fine-tuned

Having watched more than a few creationism-debunking videos, mostly on YouTube, I've noticed a recurring phenomenon. The debunker competently addresses every argument the creationist puts forth… until the topic of fine-tuning comes up, at which point the debunker falls flat on his face, totally falling for the very same logical fallacies that he's in the …

PKLITE supplement 7: Min/max alloc. part 2

This is a follow-up to Part 1. For a list of all my PKLITE posts, see the first post. I've made more progress figuring out the formulas PKLITE uses to set the "host" MINALLOC field, and the "AX register" field. There's one major gap remaining, and it looks quite challenging, so I'll go ahead and …

PKLITE supplement 6: Min/max alloc., part 1

[This post is continued in Part 2 and Part 3.] This post is part of a series on PKLITE. For links to the other posts, see the first post. I've figured out a lot about how to decompress PKLITE-compressed files. One of the few remaining loose threads is how best to restore the "min alloc" …

Spacemaker executable compression

Spacemaker is an executable compression utility for MS-DOS executable files. It was developed by a company named Realia. (This post assumes you know something about MS-DOS executable files, and the concept of executable compression.) The most notable thing about Spacemaker is how old it is. A magazine ad confirms that it existed, in some form, …

The easiest unsolved math problem

Consider any prime number $latex p$. Compute $latex 2^{p-1}-1$. For example, if $latex p$ is 11, this makes 1023. Now take the number 1023 and divide it by $latex p$ (11). Do we get an exact integer? Yes, we get 93. (And we will always get an integer, by Fermat's Little Theorem.) Now take that …

Details of Okumura’s LZSS compression

In this post, I'll write something like a specification for the compressed data format we might name "Okumura's LZSS". I'll shorten the name to just "LZSS", but be advised that "LZSS" can have a much broader meaning in general. The audience is someone who already has a basic understanding of "LZSS" and "LZ77" compression. I've …

Notes on PFS:First Publisher ART format

For today's exercise in digital archeology, I'm taking a look at the simple bitmapped graphics file format commonly called something like PFS:First Publisher ART. PFS:First Publisher is a desktop publishing program, dating back to 1987. The relevant versions of it are for MS-DOS. ART is not the main file format used by the software; it's …