Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!wuarchive!zaphod.mps.ohio-state.edu!rpi!crdgw1!ge-dab!peora!tarpit!bilver!bill
From: bill@bilver.UUCP (Bill Vermillion)
Newsgroups: comp.sys.tandy
Subject: Re: Model II, 12, 16
Message-ID: <396@bilver.UUCP>
Date: 9 Dec 89 18:19:08 GMT
References: <1392@ucf-cs.UCF.EDU>
Reply-To: bill@bilver.UUCP (Bill Vermillion)
Distribution: na
Organization: W. J. Vermillion, Winter Park, FL
Lines: 54

In article <1392@ucf-cs.UCF.EDU> wordproc@ucf-cs.UCF.EDU (wordproc) writes:
>
>I have seen the innards of a Model II and a Model 16 on numerous occasions,
>either to work on them or whatever.
>
>The other day I saw a Model 12 with the back opened up, and was amazed at the
>fact that it did not resemble either the II or the 16 internally!  The boards
>and slots are mounted horizontally like the shelves in a bookcase rather than
>vertically as in the II and 16 machines.
>
>Does the 12 take the same boards (hard drive controller and so forth) that the
>II and 16 take?  Why the different configuration?  
>
>Seems like a good way to create problems with cards
>over a long period of time, with card bending and warpage and so forth.

The 16 (sometimes called the 16a) was derived from the model II chassis.
The boards were vertical.   And they are held in place by one metal bar with
slits and a rubber bumper.  (I just double checked as I have my 16 apart at
the moment).

When the 16 came out the only memory boards were 256k.  With the bus structure
you could get 512k in a 16 and have two users.   

The 12 went to a bus with two more slots, and the 16B and the 6000 uses the
bus structure there.  The horizontal bus mounting is more secure and there are
no problems with flexure and shorting. This node is running on a 6000 and 
I have a 1 meg board in it that is a 512 piggybacked with the other meg,
to give me 2 megs of system memory with the mmu upgrade.  (My 2 meg board is
a bit sick at the moment)

By going to the additional spaces you could then put in the additional serial
ports and have room for the Bernouli box. Scrap the Bernouli and you can have
another 3 port card for 9 users.  (Over 9 users you go to the Model 12000,
which is a modified Model II box with an extended bus structure. This requires
a custom kernel - and is expensive.  The "12000" is made by Snapp (or was) and
will support 15 users.  He can also hang about 8 250meg drives off the system
if you really want).

So the additional bus structure is a plus and is better.  However more boards
caused a cooling problem, and some B's with the turbo mods sound like a fan
factory - there are 3 fans in those systems.

With a 6000's bus structure you can go to the full 4 megs of accesible RAM,
run 6 users, and a B'box.

When I had the 1 meg card in the 16 I had to put a fan on top blowing down to
keep the board cool.  The 6000 cooling design is also much better - if you
don't mistakenly leave the back cover off.


-- 
Bill Vermillion - UUCP: {uiucuxc,hoptoad,petsd}!peora!tarpit!bilver!bill
                      : bill@bilver.UUCP