Whatever happened to …

… ARC files?

You’ve got to go back, way back, if you are wondering this yourself.

At the time, I was running a BBS (Bulletin Board System) on an MS-DOS system for my students to upload computer documents to me and I had a public side for other things.  One of the other things was the sharing of documents or files with others.  Since we used modems of varying speeds (none of which were really fast by today’s standards), there was a desire to compress the files so that they were smaller in size to speed up the transfer process.

One of the first popular compression formats was .ARC.  Everyone arc’ed their files and shipped them along.  ARC wasn’t built into any operating system and that started a real battle.  You had to download a utility to do that and there really only was one in the beginning – from Systems Enhancement Associates.  Bonus marks if you remember SEA.

Technology loves a champion and the champion in this field was Phil Katz who created his own ARC program.  It worked faster than SEA’s and a lot of people, including me, moved to it.  Then, there were lawsuits and all kinds of nastiness.  So, Katz created another archiving format that was even faster – ZIP.  The program was released as shareware and I paid to get the registered version.  That allowed me to brand the ZIP which was kind of important at the time.  I was writing Doors (external programs to BBS systems) and they had multiple files to make it all work.  ZIP let me package them all together into a single compressed file and my brand let people know that it came from me.  Extra bonus if you remember Bay Street Bulls.

You still see ZIP files today as compressed archives.  It’s just that good.  The concept is available on all platforms and other methods based on the same premise are used to get large files from point A to point B and remain intact.

In the Computer Science classroom, there are various problems to solve that involve analysing string of characters and then compress them using many of the techniques in ZIP.  A popular one is Run Length Encoding (RLE).

zip

For a Sunday, your thoughts…

  • What was your first archiving program?
  • Where do your allegiances lie – ARC or ZIP or something else?
  • Do you even see or notice that you’re downloading a compressed archive composed of many files when you get a new program online?  Or, does the magic just happen?
  • Do you worry about file sizes when you send or receive something or has today’s faster connections made it just another fond technology memory?
  • Have you ever written code that takes a string and shrinks it using techniques like RLE?

I’d be interested in hearing your thoughts.  Please let me know in the comments below.

The entire list of posts in this series is available here.

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3 thoughts on “Whatever happened to …

  1. Ah yes – ark then zip – I seem to recall using pkarc or pkzip but the memory is fuzzy.

    I also liked the juxtapositon of how arc or zip compressed vs the Unix way – at least as I recall.

    Arc and Zip I think compressed each file and then packaged them while in Uniz, you’d tar all the files together and then compress the bundle. The Unix way led to the ability to exploit similarities between files for theoretically better compression but also meant you had to decompess the whole thing to extract any single file. The arc/zip on windows method, the oposite.

  2. This got me thinking of a little known and little used compression. File names were once limited to 6 characters with a three character limit on file extensions. Some operating systems I used to work with stored these names and extensions in three 16 bit words. Now since ASCII is normally 8 bits a character this would seem to be a problem. The answer was a very limited character set for file names and a system called Radix-50 (rad50 for short) Saving three bytes was worth the effort back when a large disk drive was less than 100 MB and cost more than a small house.

    I may or many not have written a program to use this encoding and decoding scheme today because I’m a geek.

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