🚀 go-pugleaf

In article <1990Nov08.025521.20590@ecst.csuchico.edu> mrush@ecst.csuchico.edu (Matt "C P." Rush) writes:
>In article <15683@cbmvax.commodore.com> daveh@cbmvax.commodore.com (Dave Haynie) writes:

>>The most recent such change was rather trivial -- the A3000 got a different 
>>realtime clock, so that we could have a small amount of battery backed RAM 
>>for the software folks to play with.  

>	Does this mean we can have a REAL "Clock Virus" now?  Oh boy, viri
>that survive Power-Down...

Man, some of the rampant paranoia going on.  If you worry TOO much about
disease, you're never going to have any fun.  

NO, YOU CAN'T HAVE A CLOCK VIRUS.  There's only a tiny amount of RAM in there 
in the first place (don't recall exactly, something like 64 bytes, or was it 
16...).  Secondly, as mentioned at least a zillion times back when clock virus
rumors went around the first time, the clock is only a 4 bit device.  There is
no 680x0 family processor that can execute code out of any 4 bit memory.  On 
the 68000 you must have 16 bit memory, on the 68020/30 you must have at least 
8 bit memory, and at that it must be on D31..D24 and mapped as an 8 bit port
(I think the clock is still mapped as a 16 bit device, like in the 2000, though
I could be wrong).

>	PLEASE tell us there is SOME protection against "incorrect" usage of
>this battery backed RAM (other than the obvious 'the CPU must be TOLD to 
>execute this RAM')...

That's not a trivial excuse, anyway.  What clever virus could you write with
16-64 bytes of battery backed RAM that must be triggered by a disk loaded
routine anyway that you couldn't write without the battery backed RAM.  Note
also that the code would have to be very careful about its instruction mix,
since those bits mean something to a number of OS elements that wake up long
before the virus could ever be activated, and if the wrong bits are set, 
they could easily be reset by the OS.

But, again, it's a non-problem.

>>Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests"

>	-- Matt
-- 
Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests"
   {uunet|pyramid|rutgers}!cbmvax!daveh      PLINK: hazy     BIX: hazy
	Standing on the shoulders of giants leaves me cold	-REM