Re: Tux 2 patents

From: Timothy Roscoe (
Date: Mon Oct 09 2000 - 13:13:52 EST

For what it's worth, the system was called "Jackdaw" and was written by
Mike Challis. It was in extensive use on the University's MVT/MVS/MVSXA
mainframe for many years as the database for holding user information. The
document Alain's got is probably Computer Laboratory Technical Report no. 1
(yes, One!).

If it isn't, and you need it, see

Jackdaw was phased out when the mainframe was decommissioned about 5 years
ago. Mike's still around, but I think he's retired.

  -- Timothy

At 10:00 PM 10/5/00 +0000, Alain Williams wrote:
>I remember when at the University of Cambridge (in England) about 25 years ago
>seeing some work then about the Jackdaw (or was is Jackard) database system
>that had the great feature of being immune to OS crashes, it used a phased
>update mechanism where new blocks were written to disk and the last block
>written was the one that contained the switched pointer, until this last block
>had been written the changes had not been made. Since the write of a disk
>was atomic the database would never be corrupt.
>If someone wants I think that I still have a (paper) copy of the report
>this. I can send/fax a copy if wanted.
>I don't subscribe to this list, so please reply direct if someone wants it.
>(Please don't request a copy just out of curiosity since I don't want to have
>to post/fax copies that won't help resolve this case by showing prior art.)
>Alain Williams
>To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
>the body of a message to
>Please read the FAQ at

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
Please read the FAQ at

This archive was generated by hypermail 2b29 : Sun Oct 15 2000 - 21:00:12 EST