Slim! homepage

• Introduction
• System requirements
• Download latest version
• Other downloads
• Compression links
• About author

Introduction

Slim! is a powerful experimental compression utility, bundled with basic archiving functionality. Its primary purpose is to achieve maximum possible compression level, disregarding compression speed and memory requirements. Early Slim! versions use PPM* compression method, version 0.021 is probably the best PPM* implementation if judged by compression ratio. Since version 0.22 Slim! uses the progressive PPMII core, developed by Dmitry Shkarin.

System requirements

To run Slim!, your system has to meet following minimum requirements:

• Intel Pentium III/Celeron CPU or higher, AMD Athlon/Duron or higher. It may run on other IA32-compatible processors, but no tests were performed to ensure this.
• 256+ Mb RAM, the more the better. To achieve very good compression, at least 128Mb should be allocated only for PPM model, without taking in consideration other allocations and OS memory demands, so while Slim! will run with less than 256Mb of RAM, its performance will be less than acceptable.
• Microsoft Windows 2000 or Windows XP. Slim! may run succesfully on Windows 95/98, but no tests were performed to ensure this. I do not plan to port Slim! to other OSes.

Latest version

The latest version is Slim! 0.23d. It features:

• Improved EOL coder. Text files with strong, consistent formatting like stand.txt from  VYCCT are the most affected.
• Improved SSE modeling and weighing. In general the compression is better, with far less penalty on pre-compressed files like PDF and JPEG. However, there's a slight setback on some types of image files.
• Memory required for SSE model is slightly reduced (that's a bug-fix, actually)

Other downloads

Older versions of Slim!

• 0.22
• 0.021 (the last version based on PPM*)

Compression papers

• Dmitry Shkarin's “Improving the Efficiency of the PPM Algorithm”
• Szymon Grabowski's “Text Preprocessing For Burrows-Wheeler Block Sorting Compression”
• N. Jesper Larsson's “Extended Application of Suffix Trees to Data Compression”
• Juergen Abel's “Text Preprocessing for Data Compression”

Source code

• Dmitry Shkarin's x86 disassembler skeleton
• N. Jesper Larsson's implementation of sliding window algorithm
• Eugene Shelwien's set of rangecoders
• An implementation of sequitur algorithm

Compression links

Compression benchmarks, tests and challenges

• Werner Bergmans' Maximum Compression
• Vadim Yoockin's Compressors Comparison Test
• Johan de Bock's GIMP Source Compression Test
• Alexander Ratushnyak's Artest
• Emilcont Ultracompression
• Leonid Broukhis' Calgary Corpus Challenge
• Jeff Gilchrist's Archive Comparison Test (outdated)

Homepages and compression related sites

• Dmitry Shkarin (PPMd, PPMonstr and DURILCA author)
• Eugene Shelwien (PPMY and Ash author)
• Maxim Smirnov (PPMN author)
• Serge Osnach (Enc and Epm author)
• Andrew Filinsky (Bee author)
• Matt Mahoney (PAQ author)
• Frank Schwellinger (Ocamyd author)
• Malcolm Taylor (RK, RKC and WinRK author)
• Yaakov Gringeler (Compressia author)
• Przemyslaw Skibinski (WRT author)

About author

• Name: Serge Voskoboynikov
• Nickname: Gray
• Birth date: July 13th, 1977
• Birth location: Severodonetsk, Ukraine
• Current location: ZTN, near mega ;-)
• Bad habits: none, but I'm notoriously lazy
• Good habits: a lot of them ;-)
• Temper: far from nordic
• Hobbies: programming, Q3, HoMM3, NFSU, NWN, swimming, reading fantasy books
• e-mail:
• icq: 53184547

Web desing notes

In process of creating of this page, I ran into following browser bugs:

• Opera doesn't follow right-hand side links. Really annoying, fixed with javascript, but it works only after page was fully loaded and ruins navigation if CSS is turned off. I hope that those who browse my page without CSS will also have no javascript.
• Opera improperly highlights the word preceding <a> and <abbr> tags on line breaks. I have reformatted text to avoid this glitch.
• Mozilla and Opera don't handle mouse wheel scrolling of frames that have overflow property set to auto. Mozilla's bug fixed by javascript. For Opera I don't know any workarounds, but scrolling works after a mouse click on the frame.
• MSIE 6.0 doesn't show <abbr> tag. I don't use Dean Edwards' workaround because it breaks validation.

Please let me know if you know the way to work around these problems with pure CSS, or if you spot any other quirks (note: I won't use non-validating fixes on my page). Also, my English is far from being perfect, feel free to notify me about any misspellings or bad phrase constructions.

“plastic toy” design by Gray, © 2004