Amiga - 500/500Plus ROM switcher.
A switcher lets you use more than one
ROM on a computer and allows you to
switch between them.
There is generally a small pcb that
holds the two ROMS... Say 1.3 and 2.04.
Often the card is connected to a switch.
Or the switch could be a software switch.
The ribbon location can vary, given that
the cable to the switch exits behind
the floppy drive.
This switcher is mounted on an A500
motherboard in a Checkmate.
I made some reference pics from today's
shoot so I can use them in the future.
These pics show the controls on the 1084S.
The rear of the floppy drive with
an ON/OFF switch.
The tank mouse I chose to use.
This switcher has an external switch.
Quite common for an A-500 Plus to have a
switcher so that it can access the 1.3 ROM.
I use an external drive when I have no
hard drive sidecar connected.
This machine has a very strange history
so don't ask about the red light.
The stickers tell me what the machine
is fitted with internally plus RAM.
I always sit the floppy on a sheet of tissue.
So we can switch from the 1.3 ROM ..
And then to the 2.0 ROM.
Let me show the problems with Workbench 1.2.
First up we have no RAM disk.
No facility to view hidden files.
Various commands missing from AmigaDOS.
Next up the problems with 1.3.
This time we get the RAM disk.
But can still not see hidden files.
We do get the added AmigaDOS commands though.
So what happens if you try to use the
Workbench 2.04 disk whilst switched to 1.3.
So let us flip that switch to the 2.0 ROM.
Same computer but now able to access
the 2.04 Workbench and disks.
Note the grey and Workbench on the left.
And we are able to show all files.
And there are the hidden drawers.
Plus all of the hidden AmigaDOS commands.
And a far more informative AVAIL command.
The SHELL/CLI also shows 1.Workbench2.0:
2.04 also comes with a hard drive controller
and the incredibly useful HDToolbox.
2.04 has way more functionality.
More reference pictures. Note the ECS
AGNUS at 2 Meg plus the ECS DENISE.
And 2MB CHIP RAM.. even though the Plus
came with just 1MB. So an extra 1MB CHIP.
And now with the switcher we can view
the hidden files on the 1.3 Workbench
disk and start editing stuff and the like
for when we use the 1.3 software etc.
And we can add to the stock of AmigaDOS
commands, and write mount files and
create configuration files etc. All so
much easier with a ROM/WB that can view
and edit files from the actual Workbench.
And when done you can revert back to
the 1.3 ROM and test your programs.
So why have the 1.3 ROM. Some games will
not work on the later ROM.
