From mboxrd@z Thu Jan 1 00:00:00 1970 From: pechter@gmail.com (William Pechter) Date: Mon, 28 Mar 2016 10:32:53 -0400 Subject: [TUHS] PDP-11/70 SPL (was: Early non-Unix filesystems?) In-Reply-To: <20160328135040.7CF8D18C0B6@mercury.lcs.mit.edu> References: <20160328135040.7CF8D18C0B6@mercury.lcs.mit.edu> Message-ID: The 11/70 with Mr memory had battery backup on the MOS usually so they would have the saved memory content unless they powered off the battery backup. Sent from my android device. -----Original Message----- From: Noel Chiappa To: tuhs at tuhs.org Cc: jnc at mercury.lcs.mit.edu Sent: Mon, 28 Mar 2016 10:18 Subject: Re: [TUHS] PDP-11/70 SPL (was: Early non-Unix filesystems?) > From: Dave Horsfall > That makes sense, and someone forgot to document it... Or perhaps it was added precisely to get rid of the window, and then someone discovered that it could be used to freeze the system, so they decided they'd better not document it? If the system had MOS memory, and you had to power cycle the machine to get it out of this state, there wouldn't be any evidence left of who did the deed (unless the system was writing extensive audit trailing to disk), so it would be a great 'system assasin' (aka vandal) tool. Noel PS: I guess this is more PDP-11ish than UNIXish - apologies for the off-topic!