🚀 go-pugleaf

I recently was testing a possibly defective A501 RAM/Clock card [damn
Christmas returns, I hate 'em] for a customer's A500.  I noticed that
different amounts of RAM were free on each boot-up.  I was always
booting on the same disk so I thought that it might be the card.  The
difference was usually about 30-150 bytes or so, and the systest
program showed no problems, [and I did a lot of swapping with the
store's equipment and the customer's equipment] and I concluded that
the card was OK.

I did find that the amount of free-RAM on an A500 is different
depending on how you boot it.  I haven't tested this out on my B2000
at home yet.  Here is what I found:

2 different variables.  Each test performed with only one change in
variable.
	Variable 1 - machine state before boot: OFF (the machine was
off) or REBOOT (the machine was on, and was rebooted).
	Variable 2 - did I wait for the "WorkBench" request: SCREEN
(yes, the screen was displayed) or NOSCR (the disk was inserted before
the A500 had a chance to display the request)

All tests performed on a A500 with A501 card.  Kickstart 1.2 and
WorkBench 1.2 33.61.  The disk was a virgin AmigaDOS disk (as far as I
know :-).  The test was ran twice with different results.  A lot of
customers started coming in so I had to stop experimenting.  Later I
tried repeating a particular combination (didn't record the results)
and got varying answers like I did here.

		First Run	Second Run
Var-1	Var-2	Free Memory	Free Memory
OFF	SCREEN	926288		926320
REBOOT	SCREEN	926288		926344
OFF	NOSCR	926408
REBOOT	NOSCR	926384
REBOOT	NOSCR	926408
  "	  "	926384
  "	  "	926384
  "	  "	926384

So, it looks like the code that displays the friendly hand with a
workbench disk isn't freeing all the memory it could.  You can
reliably get 96 extra bytes by not displaying that screen.  It also
looks like there is a random 24 bytes that do or don't appear
depending on the phase of the moon. :-)

Now I'm not the person that complains about 120 missing bytes, but I
thought that this was an interesting point.  Maybe I'm just wasting
bandwidth or maybe someone will research the code that does this and
find a tiny yet-undiscovered bug that, when fixed, will result in
fewer crashes, world peace, and better TV sitcoms. :-)
("Then Tom woke up and realized it was all a dream...") :-)

...or maybe this is a "known bug" slated for fixing in 1.4.
...or maybe I've been working too hard.

-Tom
-- 
   Tom Limoncelli   Drew University    Madison NJ    201-408-5389
       tlimonce@drunivac.Bitnet          limonce@pilot.njin.net
 "Fences make good neighbors" -Frost       "I want an MMU" -Me
    Standard disclaimer?  No, we're still on the dpANS disclaimer.