[ale] Chip upgrades and making them work

[Dan Newcombe]

I'm also sending this to the list in case I mess up, someone can 
correct me.

> First:  in upgrading just a chip (say 386 --> 486), does the motherboard
> impose a restriction on . . . correction, *how much* of a restriction does
> the motherboard place on the upgrade.  E.g., is the upgrade restricted to
> the same clock speed as the original chip?

The clock speed is determined by either a clock crystal (which is 
usually hardwired to the motherboard) or by a jumper/dipswitch for 
those nice boards that can handle different speeds (like mine :)  The 
other "restriction" is whether or not the board can handle the new 
chip.  I think there were some 386/486 boards, but they were not that 
widespread.  
 
> Second:  in upgrading the motherboard and chip, what restrictions should
> I expect from the rest of the system?  I know, for example, that my 30 pin
> SIMMs would not be kosher in current motherboards which use 72 pin, so all
> of my RAM would have to be replace with the board.  Likewise, would I need
> a new power supply to supply 3.3 volts instead of 5 volts, or is there a 
> transformer somewhere on the board itself to make that switch?

One of the main ones is making sure the puppy will fit in the case, and 
be able to be mounted to your case.  While I have not had a problem 
when buying things piece by piece, some companies have cases which only 
thier boards will fit in.  This is usually the case in slimline cases, 
like Packard Bell's.  The desktop/tower's usually use standard sized 
parts.

Simms - You may (or may not) need to keep this in mind when buying.  
This is a flexible area, as you can get boards which can handle lots of 
different memory configs.  Mine has 8 30pin simms and 2 72pin simms.  I 
actually saw some with more!!!  Usually though, the more simm slots you 
add, the less # of slots you have for expansion.  There are also 
simmsavers which allow you to put 4 30pin sims into a 72pin slot, and 
many other combinations.
	The other consideration (the worse one) is that your old memory may
be very slow.  Most boards I've seen will add wait states to let the 
memory catch up, but make sure if you buy a new board that it doesn't 
require certain speed simms.

Power - the motherboard should take care of this.  the supply will feed 
the motherboard which should take care of giving out the right amount 
of juice.  The rest of the devices will still need thier 5/12 volts.

Other - If you get a board with a newer bus type (VLB, PCI) you may 
also wanna upgrade cards to get the most out of it.
 
> And finally, the Linux bit:  given a upgrade (of either of the above 
> formats) what would I need to do to kmake Linux recognize and use the new
> stuff?  I can assume that if I got a PCI motherboard I would have to 
> compile in the PCI_BIOS portion in the kernel, but what else?  Would 
> everything just be recognized on the fly and all be light and happiness?
 
> I'm currently running a 386sx/20, and have an option on a 486DX2/66 from
> a friend.  My mouth is watering, but I don't believe that I could just
> install the new chip and go.  Figured I'd make sure, though:  I'd hate
> to pass up a good deal on my own faulty knowledge.

You would DEFINATLY need to buy a new motherboard.  this is like trying 
to fit a V12 in a Ford Escort!!!  you can get a board for the 486DX2/66 
for under $100.  I would not go PCI with a 486, unless you wanna get 
some PCI cards, and in the future move to a PCI/Pentium motherboard.  
The nice thing about VLB is you can put old ISA cards in it...not so 
with PCI.

But on the linux side, if you installed a new board, then you should be 
able to "just go".

	-Dan

--
Dan Newcombe - Clayton State College - User Services - 770-961-3421 
newcombe at aa.csc.peachnet.edu  http://www.csc.peachnet.edu/home/dan/
-  And then one day, hooray, another way for gnomes to say, Hooray!
                                    Pink Floyd, The Gnome