Universal Amiga Emulator
Les Pounder loved his Amiga 500 and in this tutorial he shows us how to recreate the golden years of computing, via the powers of emulation.
The Amiga is close to Les Pounder’s heart, and here he recreates the golden age of computing.
Back in the 1980s there were a number of home computers from various companies, including Amstrad, BBC and Sinclair. But one company, Commodore, released a computer that transcended the 8-bit era and led to a computing revolution.
The Amiga range of home computers offered something different. An internal 3.5-inch floppy drive, 512kb of RAM that was expandable using an add-on board, and compatibility with peripherals to manipulate and create content for television (the early series of Babylon5 used content generated on an Amiga 4000 with the Video Toaster add on).
The Amiga also had a healthy magazine following, including AmigaFormat whose erstwhile editor Nick Veitch went on to found a periodical called LinuxFormat ( Amiga Computing 4ever!– Ed). In this tutorial we shall have a little fun and create our own Amiga 500 using a Raspberry Pi 3, and then play a classic game!
Fat Agnus!
For this project we’ll be using Amibian, a Raspbian-based operating system for Amiga emulation. It includes a user interface for the UAE (Useless/Universal/Unix Amiga Emulator… it has many names!) that enables us to configure the emulator. To download Amibian head to https://gunkrist 79.wixsite.com /amibian and click Download and extract the image file from the archive.
As well as downloading the emulation software, we also need to download Etcher, which is an easy-to-use SD card imaging tool. It’s a graphical tool for those that find dd a little daunting. Download Etcher from https://etcher.io and then extract it.
To use Etcher, go to the folder where it’s been extracted and double click its icon. Etcher is a self-executing file, so it can be directly used. Once Etcher opens you have three steps to follow. The first is to select the image to write to the microSD card. In this case it’s the Amibian image. Next, select the drive to which the image should be written. Typically, Etcher will correctly identify the drive to use because it looks for large hard drives and ignores them in favour of smaller SD cards. Finally, clicking Flash will write the image to the microSD card. Note that you’ll need to enter your password in order to flash the image!
The flashing process should take no longer than five minutes. When it’s finished, close Etcher and remove the microSD card, but then pop it back in so that it can be mounted for use.
Our next step is to obtain the Kickstart ROMs (the BIOS of the Amiga) so that we can boot the emulator. If you have an Amiga already then there are ways of obtaining your own image of the ROMs, but the easiest and legal way to get the ROMs is to purchase the Amiga Forever Essentials app for Android ( www.amigaforever.com/ android) and then copy the ROMs to your computer. The app costs £1.39 and it provides legal access to all of the Kickstart ROM files for the Amiga 500 to the 4000 (OS 1.3 to 3.1).
With the Kickstart ROMs to hand, we now need to copy them into the Kickstart directory of the Amibian SD card. This directory is in the largest partition of the microSD card, and it’s in /root/amiga/kickstarts. Because this folder is owned by root, we need to either copy the files using the terminal as root, or run the file manager as root. Choosing the latter means we can drag and drop the files to the correct folder: $ sudo -i nautilus
Not again Paula!
The Amiga primarily used floppy disk (3.5-inch, 880kb) and these disks contained games, applications and the operating system called Workbench. If you already have your disks to hand, you can create images of them using software on the Amiga. There are many websites offering ADF files (Amiga Disk Files) that are images of floppy disks, but their legality is dubious at best because they’re not strictly “abandonware”. So we’d advise caution if you follow this route.
For this tutorial we already had an ADF of Workbench 1.3, the classic strategy game CannonFodder and an original AmigaFormat issue 10 cover disk. We used EasyADF ( http://bit.ly/easy-adf) to create ADF images of our
floppies. Then we copied the ADF files to the floppys directory located in /root/amiga/floppys.
With those copied across, unmount the microSD card, insert it into the Raspberry Pi 3, connect your peripherals and boot into Amibian.
Kickstart me
On first boot we see the Amibian logo, and then after only a few seconds the user interface appears. To the left are all of the configuration options available (RAM, ROM, CPU and so on) But for this first boot, let’s click Quit to take us to the command line. We need to use the Amibian command line, so from the text menu select option 6 (Settings) and press Enter. Then in the next screen type the following to use raspi-config: $ raspc
In raspi-config, select the menu option to expand the filesystem and then press Enter to start. For the change to take effect we’ll need to reboot and return to the Amibian user interface.
Denise hold and modify
The Amiga 500 came with 512kb of RAM (upgradable to 9MB) and the CPU was a Motorola 68000 running at 7.09MHz. Despite this rather meagre-sounding spec, the Amiga was a powerhouse of its time that was capable of multitasking operations, playing digitised video and displaying up to 4,096 colours on screen (in HAM mode).
We’re going to configure a basic Amiga 500 with 1MB of RAM. First, go to Configurations, create a new configuration as <YOUR NAME> Amiga and click Save. Next, move on to CPU and FPU and set the CPU to 68000, FPU None, and CPU Speed as 7MHz. Then move on to Chipset. For this, select OCS, Blitter to Immediate, and don’t tick the the Copper box. Next, move to ROM and using the … button open the dialog and navigate to /root/amiga/kickstarts. You’ll see the Kickstart ROMs that we copied there earlier. Select the
amiga-os-130.rom (or whatever your 1.3 Kickstart ROM is called) and then press OK. Now set the RAM for the Amiga. Set the Chip RAM to 1MB (an expanded A500.)
In order to play a game we need to insert the floppy disk(s) into the Amiga. The Amiga could have up to four floppy drives (one internal, three external), and for our demo we played CannonFodder which came on three floppy disks. So we enable DF0 (internal) and used the … menu to locate the game’s ADF image that we want to play. The last configuration step before playing the game is to configure a joystick. If you have a USB joypad/stick then Amibian should detect it and configure it, but you can tweak it using the Input configuration option. Remember to save your setup for your next gaming session using the Configurations option.
Rock Lobster time
After all that tinkering we can finally play the game. Amibian will emulate the speed of an Amiga floppy drive, so don’t worry – your game will load in a minute or so! If you can’t wait, click F12 to open the user interface, go to Floppy Drives and change the emulation speed to suit your patience. F12 can also be used to change configurations, load a new floppy disk and reset the Amiga should the game crash.
So there we have it, an emulated slice of video gaming and computing history, and something that brings back many wonderful memories for us at LinuxFormat.