Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!crdgw1!crdos1!davidsen
From: davidsen@crdos1.crd.ge.COM (Wm E Davidsen Jr)
Newsgroups: comp.arch
Subject: Re: Hamming code (or other) for 4-bit correction?
Message-ID: <3288@crdos1.crd.ge.COM>
Date: 25 Mar 91 14:53:13 GMT
References: <16045.27ed2f20@levels.sait.edu.au>
Reply-To: davidsen@crdos1.crd.ge.com (bill davidsen)
Organization: GE Corp R&D Center, Schenectady NY
Lines: 21

In article <16045.27ed2f20@levels.sait.edu.au> marwk@levels.sait.edu.au writes:
| Suppose one has 32-bit words and 8 more bits/word for error detection and
| correction.
| 
| (1) Can the hamming code for 32-bits (requiring 6 bits) be modified
|     to detect 2-bit errors (as well as correct 1-bit errors)?

  Yes, but I'm not sure it's called Hamming, I just can't remember what
it should be called.

| (2) How about correcting 4-bit errors?

  You are getting into the area of Fire codes, and I think people are
still writing theses about it. I used to understand it, mostly, while
reading the papers. I don't now.

  Please enter theorist, stage left...
-- 
bill davidsen	(davidsen@crdos1.crd.GE.COM -or- uunet!crdgw1!crdos1!davidsen)
        "Most of the VAX instructions are in microcode,
         but halt and no-op are in hardware for efficiency"