Date   : Fri, 24 Jul 1987 17:06:33 GMT
From   : tektronix!reed!percival!gary@ucbvax.Berkeley.EDU (Gary Wells)
Subject: Re: No-slot clocks

Carefull on those no slot clocks!  They should work ok on any type of system, 
but not all NSC's are accessed equally.

We evaluated a couple of different brands here.            

Brand A: Waited & monitored all accesses to its memory location, looking for a
specific sequence of bytes.  When the "attention" sequence was detected, the
next set of bytes was intercepted & taken to be set/read commands.  This is
probably OK, as long as you are POSITIVE that there will be no interrupts
during the time you are trying to access the clock (we were positive that there
would be)

Brand B: Was actually a 2K x 8 RAM.  This replaced your existing 2K x 8 device,
was accessed and used just like normal RAM, except that the top 16 bytes ALWAYS
contained the time/date info.

So check your specs sheets BEFORE you buy one of these beasts.

-- 
Wudda yeah mean, I'm gonna get in trouble?  I AM in trouble!

...tektronix!reed!percival!gary