From mboxrd@z Thu Jan 1 00:00:00 1970 From: paul.winalski@gmail.com (Paul Winalski) Date: Mon, 28 May 2018 18:32:23 -0400 Subject: [TUHS] Control-T (was top) In-Reply-To: References: <20180524122021.857BC18C09A@mercury.lcs.mit.edu> Message-ID: On 5/24/18, Arthur Krewat wrote: > > * a DZ11 is UNIBUS and was only available on a KS10 - but I'd imagine > any straight serial port on a KA/KI/KL10 would do the same. If you were, > say, on a DCA mux, that had a 14.4K serial link straight into the > UNIBUS, there was much less of an effect. DZ11s were available on PDP-11s and VAXen as well as the KS10. Because the controller had no buffer it was dirt cheap. OK, perhaps, for a realtime or lab application, but if you were doing timesharing it could bring the CPU to its knees in short order. Some idiot decided to use the same idea (no buffer in the controller) to reduce the cost of the TU58 (aka DECtape II), Unlike the original DECtape, which was extremely reliable, the TU58 was prone to frequent data overrun and underrun errors even if you set things up such that it got top scheduler priority. -Paul W.