Questions tagged [compression]

Lossless and lossy data compression: algorithms and utilities.

Filter by
Sorted by
Tagged with
12 votes
1 answer
391 views

What are these compression types in the ARC file format?

The file format of the SEA ARC compression tool, also used by the PKWare PKARC tool, allowed the following compression types: Packing (RLE encoding) Squeezing (static Huffman coding) Crunching (LZW)...
  • 16.6k
9 votes
1 answer
905 views

Was there a compression program based on the Mayne-James algorithm?

Before the advent of Lempel-Ziv family compression algorithms, there was an algorithm for "Information compression by factorising common strings" by A. Mayne and E. B. James (1975), based on ...
  • 16.6k
9 votes
4 answers
1k views

Compression techniques used in old ZX Spectrum tapes

Many ZX Spectrum games* (and demos) would improve loading time and save space in the tape using rudimentary compression. During decompression, the game would display "decrunching" for ...
  • 1,860
8 votes
0 answers
408 views

What is the origin of executable compression?

According to the wikipedia article on the topic, the earliest executable compressor listed is Realia Spacemaker for IBM PC (since 1982, written by Robert B. K. Dewar, SM.COM, signature "MEMORY$&...
  • 16.6k
4 votes
0 answers
523 views

What data compression did Donkey Kong Country use?

Donkey Kong Country was among the most ambitious, popular and influential of Super Nintendo games. Technically, its big trick was taking animations rendered on Silicon Graphics workstations and ...
  • 49.8k
5 votes
1 answer
172 views

What was the first database to start compressing in situ?

The obvious way for a database to store data is with each record in a contiguous chunk, and each field having a fixed size and offset in the record. Joel Spolsky praises that way of doing things: ...
  • 49.8k
6 votes
1 answer
317 views

Reconstructing uncompressed program from compressed tape image

I have a C64 program in a .t64 file. If I load it into an emulator, what I see is that it loads into a cracktro, which then proceeds to uncompress (taking several seconds at 100% speed) the original ...
  • 2,543
1 vote
3 answers
265 views

How do I interpret these instructions for decompressing game data? [closed]

I'm trying to write a tool for the 1994 SNES game Super Metroid that creates "out of bound" maps for each the game's rooms. To do so, first I need to extract the tile-by-tile data of each room. For ...
5 votes
2 answers
1k views

Could early nineties PCs access raw CD bitstream?

In the early nineties, as discussed in What specific technical advance(s) allowed PCs to play "Full-screen full-motion" video? it became commonplace for PC games to use the storage capacity ...
  • 49.8k
20 votes
2 answers
4k views

How did the Sega CD decompress video?

In the early nineties, Sega released the Sega CD, a.k.a. Mega CD, an add-on that attached a CD-ROM drive to the Mega Drive a.k.a. Genesis. Its primary or at least most conspicuous use was for full-...
  • 49.8k
5 votes
1 answer
265 views

Can't install El-Fish on MS-DOS 6.22

El-Fish is a fish tank "game", where you have virtual fish on your screen. The game has no goal, it's more like an interactive screen saver. I got my version from a number of different sources, one ...
  • 151
24 votes
5 answers
5k views

How well known and how commonly used was Huffman coding in 1979?

Infocom's Z-Machine, designed in 1979, compresses text using a basic 5 bit code which is not very efficient in practice, achieving maybe a 1.5:1 compression ratio. Huffman coding would be far more ...
17 votes
2 answers
2k views

What is the difference between DriveSpace and DoubleSpace?

DriveSpace is the successor to DoubleSpace. Both are DOS systems that mount a Compressed Volume File as a drive, allowing ordinary programs to interface with a compressed drive without an intermediate ...
  • 17.8k
10 votes
1 answer
848 views

What is the history of data compression tools on personal computers?

On UNIX, the progression of the most widespread data compression programs was as follows: (AFAIR: Pre System V) compact (suffix .C), dynamic Huffman coding (AFAIR: introduced in System V) pack (...
  • 16.6k
24 votes
4 answers
4k views

Why does MP3 audio decoding overwhelm retro CPU's?

Many retrocomputers from the late 80s and early 90s had audio DAC hardware support. This includes the Amiga, Classic Macintosh, and PC's with SoundBlaster add-on cards. Despite the fact that the MP3 ...
  • 57.6k
23 votes
2 answers
6k views

How to convert Amiga DMS to ADF?

Our demoscene group managed to release only one demo before it fell apart, but these being the early days of the Internet in my country, and me getting lucky with obtaining access to it and creating ...
  • 6,675