posted by Mark Round on Thu 26th Feb 2004 07:18 UTC

"Emulating RISC OS, Page 3/3"
Installing the system files

The next step is to install the system files onto the emulated hard disk, as even though the core of RISC OS is stored in the ROM, many utilities and libraries are kept on the hard drive. However, there is a catch - we can download all the needed files as ZIP archives to the Windows PC, but RISC OS uses a system of 'filetypes' to identify what a particular file is. If we just downloaded these files and unzipped them on a PC, we would loose these filetypes, and they will no longer function properly. As such, I have developed a work-around but it is slightly fiddly. It basically involves getting enough of the system files identified and working working so that you can use an unzip utility under RISC OS, thereby allowing us to unzip the files properly, retaining their attributes.

First, go to The Acorn legacy FTP page at http://acorn.RISC OS.com/acornftp.htm, and download !SparkPlug, which is a ZIP-file extractor for RISC OS. Then, go to the 'RISC OS 3.7 Hard Disc contents in an Archive' link, and download all the ZIP files to your PC. The next step is to install a minimal system folder and get SparkPlug running so that the archives can be expanded properly under RISC OS and retain their filetype attributes.

Inside the RedSquirrel directory, you will find a folder called 'HostFS'. Inside this, there is another 'Disc370' folder. Anything placed in here is visible to RISC OS - it treats it as it's own hard drive, and so is the perfect method to move files between systems. Move the !SparkPlug file you downloaded (called 'dearchive.bas') into here, and rename it to 'dearchive.bas,ffb'.

Placing the comma and 'ffb' after the filename allows the emulator to identify the filetype for Risc OS - in this case, FFB is the filetype for a BASIC application - For a full list of RISC OS filetypes, see this link :- http://productsdb.RISC OS.com/sw/types.htm.

Now, you should be able to run it - back inside RISC OS, open your hard drive and double-click on the dearchive/bas icon, this should run and self-extract the SparkPlug application.

Click for a larger version We can now start to work on the System folder, called '!Boot' under RISC OS. Extract the contents of the previously downloaded 37Boot.zip and system.zip files into the Disk370 folder, using WinZIP or something similar, allowing it to overwrite any files when it asks. This will create a !Boot folder - but we will have to manually rename some of these files again in order to get a minimal system running. Again, do this by adding a comma and then the filetype after each filename. Under Windows, go into the !Boot folder, and add the following filetypes after each of these files inside it (eg: the !Boot file becomes !Boot,feb ):-

Filename inside !Boot folder Attribute to add after a 'comma' character
!Boot feb
!Run feb
Utils\BootVars ff8
Utils\DeskRun feb
Resources\!System\!Boot feb
Resources\!System\!Run feb
Resources\!System\SysPaths ff8
Resources\!Scrap\!Boot feb
Resources\!Scrap\!Run feb
Resources\!Scrap\!RunImage ff8

Reset the Acorn emulator, and start it up again. You will see a lot more output fly by, and again, you will have to enter '*desktop' to get to the GUI. Once there, open up your hard drive, and hold down shift while double-clicking on !Boot to open it. This will open another window - in this, double-click on the 'Resources' icon. This will produce an error message and a whole bunch of text editor windows. This only happens because many of the files still haven't had their filetypes set properly and get treated as ASCII text instead of being run. However, the important 'magic' has worked, so you can close all these windows down, ignore the error and run !SparkPlug from your hard drive. If all went well, you will now see it appear in your iconbar and can continue to properly unpack the system files, complete with attributes.

Click for a larger version Now, from the Windows side of things, create two folders inside the 'Disc370' folder called 'downloads' and 'newsystem'. Move all the ZIP files you downloaded from the Acorn legacy FTP site into 'downloads' - you can then drag them one at a time onto the SparkPlug icon on the iconbar. Doing this will produce another window showing the contents of the archive - drag these into the 'newsystem' folder. Once done, you should have a 'newsystem' folder full of properly uncompressed RISC OS files which we want to make our system disk. Now, quit the emulator, and in Windows, move the contents of the newly created 'newsystem' folder into the root of the Disk370 folder, making sure you erase the old temporary !Boot folder beforehand. Restart the Emulator, and you will boot straight to the RISC OS desktop, and into a fully working environment. You can then tweak the system a little - for starters, double click on '!Boot' in the root of your hard drive, and then select the 'Screen' option to increase the resolution :

Exploring your new system

Click for a larger version If you want to dabble with the RISC OS command line, select 'New Task Window' from the Acorn iconbar icon, and try starting with '*help', or you could try '*basic' if you want to flex your old-school BBC Basic skills (although, the RISC OS BASIC provides many advanced features, over and above simple 'Hello, World' stuff - you can build full GUI applications with it). If you want a full-screen command session, hit F12 and then return on it's own to get back to the desktop.

Some useful links that will provide you with information and software for RISC OS are :

Paul Vigay's RISC OS pages - A stupendous amount of information... RISC OS history, tutorials, programming information, software, FAQs and more!
Drobe Launch Pad and the IconBar - RISC OS news, articles and software.
The RISC OS Software directory - A great database of links and downloads.
AcornArcade - Gaming information for RISC OS.
Pouet's Acorn Demos and IceBird.org - classic Acorn/RiscPC demos.
RISC OS C Programming - A wealth of information on programming in C for RISC OS.

Table of contents
  1. "Emulating RISC OS, Page 1/3"
  2. "Emulating RISC OS, Page 2/3"
  3. "Emulating RISC OS, Page 3/3"
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