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From: POURNE%mit-mc@sri-unix.UUCP
Newsgroups: net.micro.cpm
Subject: writing w/o opening
Message-ID: <16696@sri-arpa.UUCP>
Date: Thu, 16-Feb-84 04:53:00 EST
Article-I.D.: sri-arpa.16696
Posted: Thu Feb 16 04:53:00 1984
Date-Received: Mon, 20-Feb-84 02:03:17 EST
Lines: 19

From:  Jerry E. Pournelle 

it's not. sigh
    Date: 24 Jan 84 15:06:00 EST (Tue)
    From: Mike Ciaraldi 
    To:   Info-Cpm at brl-vgr.ARPA, w8sdz at brl.ARPA
    Re:   writing w/o opening

    Under MP/M, there is a checksum in the FCB.
    This gets set when you open the file, and you cannot
    read or write on the file unless this checksum is correct.
    So, the problem of wiping out your directory by not
    opening the file first should not occur.

    I don't know if this technique is used in newer products
    such as CP/M-86 or CP/M-Plus

    Mike Ciaraldi
    ciaraldi@rochester