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ScuzzBlog: Diaries February 2022

Entry 12th February 2022: Post 1: Amiga 500 - 1 MB RAM Required.


Amiga 500 - 1 MB RAM Required.
I read a lot of confusing replies to threads regarding memory on
the Amiga 500. This relates on the whole to a misunderstanding
regarding chip and fast RAM. When a new user sees that a game is
in need of 1 MB RAM the responses very quickly starts talking
about the AGNUS and the capability of the particular board type
revision to expand the chip RAM.

I thought I would dispel this myth and talk in simple terms about
games requirements for the Amiga 500.

The Amiga 500 originally came with 512K of RAM expandable to 1MB.
That in truth is all that matters. When games developers made the
games for the A500 they were never anticipating the users would
start hacking their machines and upgrading chips. The way they
anticipated games buyers to respond was when a game required 1 MB
RAM they would procure a simple 512K RAM board and stick it in
the trap door of the Amiga 500. Job done. Nothing more to say.

I sense that a lot of new users are left with the idea that the
AGNUS is actual RAM and they need somehow to add 1MB to the main
memory through the trapdoor and then hacking jumpers on the board.

And so when you see a game that requires 1MB RAM just check the
trap door and if there is a card there just open the Workbench
and see if the main window shows around 800 000 free. Further
if you have a 1.3 Workbench disk open the SHELL/CLI and type in
avail and it will advise of the memory on your computer. The
board may have a switch and so make sure the RAM is 'ON'.
Sadly Workbench 1.2 does not have the AVAIL command in C.

To demonstrate matters I grabbed a very clean Amiga 500 that was
of the 1.2 era and with the warranty seal intact had never like
ever had an internal upgrade. The board is fitted with a modest 
512k AMRAM expansion board and the memory under 1.2 shows 929528 
and under 1.3 shows 876112. The machine is more than capable of
running a 1MB game like ZOOL or Vital Light. Note that I was able
to boot 1.3 on a 1.2 ROM and the 1.2 Workbench has no RAM icon
on the desktop.

Whilst the A500 is a very clean computer it has the most dodgy
sounding floppy drive imaginable. I took a video of it working.
As is with many of these very early models the power light goes
out after a while of loading a disk. That is normal.

I also show a few 500 RAM cards just for reference. Hopefully 
that all made sense. I seem to spend quite a bit of time these 
days telling folk about the 1MB issue. I do know that GOTEK and 
data pilfering with ADFs may need something different , but from 
a purely classic retro point of view what I state is true. Those
other things are not relevant to what I do here, given that an
Amiga should always have a proper floppy drive.

Video of the floppy loading

Amiga 500 - 1 MB RAM Required.


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Last updated 12th February 2022

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