Survey of EXPAND/DECOMP utilities

If you look at old DOS and Windows software distribution disks, you may see a lot of files whose names have the last character replaced by a "_" character, or sometimes a "$" character. For example: mplayer.ex_ mplayer.hl_ mplayer.re_ msacm.dl_ msacm.dr_ msadpcm.ac_ mscomstf.dl_ ... Many such files belong to a family of compressed file formats …

8 billion

Sometime earlier this month, the human population is reckoned to have reached the milestone of 8 billion. So, congratulations to us, I guess? We humans dominate the planet. The majority of Earth's good land has been taken over by us. We've increased the amount of carbon dioxide in the atmosphere by 50%. The mass of …

Is faster-than-light communication possible?

The answer to the title question is "No. But also yes." Recently, the 2022 Nobel Prize in physics was awarded to Alain Aspect, John Clauser, and Anton Zeilinger for work related to quantum entanglement and the Bell inequality. Why it was awarded now, instead of 30 years ago, is something I'm not clear on. But …

Notes on PKLITE format, Supplement 1: Descrambling

This post is part of a series about PKLITE format. For a list of all the posts, see the first post. In a previous post, I noted that some PKLITE-compressed executable files are more difficult to deal with, because most of the decompressor is obfuscated. I named the obfuscation format "scrambled". In this post, I'll …

ARJ compression method 4

ARJ is a compressed archiver utility and format, with features similar to ZIP. It seems at first to have five compression methods, with ID numbers 0 through 4. Method 0 is for no compression, so it's easily dealt with. Methods 1 through 3 are really all the same. They record how hard the compressor tried …

Survey of RAR comment formats

This post is about RAR, a file compression and archiving file format in the same category as ZIP. It's known for its association with the WinRAR software, but there are also command-line and text-mode versions of the software that are just named RAR. RAR supports two kinds of comments: A main "archive comment", for the …

Which comes first in DOS timestamps, the date or the time?

There are a lot of old DOS-centric file formats, especially file archiving and compression formats, which store timestamps of files. Most of them use the standard MS-DOS timestamp format for such things. This format is usually interpreted as two 16-bit integers: one for the date, and one for the time of day. I'm not sure, …

How to vote in a late-stage two-party system

No voting system is perfect, but one of the worst systems that is even remotely compatible with democracy is the one known as first-past-the-post. In the simplest form of this system, each voter gets one vote per contest. A contest may have more than two candidates. The candidate with the most votes wins, even if …

Notes on some old self-extracting ZIP archives

The old PKZIP compression software for DOS includes a utility named "ZIP2EXE", which turns a plain ZIP file into a self-extracting executable file in DOS EXE format. Depending on the version of PKZIP/ZIP2EXE, and the options used, there are several different ways in which this EXE file is constructed. I wanted to learn about these …

Notes on PKLITE format, Part 6

This post will explain the important differences between compressed EXE files made by the v1.00beta version of PKLITE, and those made by release versions. It is a continuation of Part 5 -- please read that first. For an introduction to PKLITE, and a list of the other posts in this series, see Part 1. History …