To: 999 (all members) From: E5F (Dick Greening) Subject: BEEB Emulators on RISC-OS Martin Hodgson's (D7X) plea for other Archie machine owners, running a BEEB emulator, did not fall on deaf ears. The reason I am late in commenting is that I have been on another planet for two months, (well BW Canals actually!) I also would be interested in buying 8BS CD Roms, but my experience in trying to unravel disc images downloaded from the Internet, has made me think again. (This used a friend's AppleMac writing to a DOS disc read by an Acorn 3010! It also included transfering the files via the RS423 from the Archie to the BEEB!....VERY time consuming. And then trying to reconstitute the double sided disc by adding together two half sized files per side with DiscDoctor!) There has to be an easier way!! Is there any bright spark out there who can write a piece of software to do the conversion? .........PLEASE! ANYWAY this may all be academic in the light of ACORN's present financial situation, (we may all be forced to use Windozzzeee........ God forbid!! I was GIVEN a 386 ...I've tried to like it.....HONEST.....It has only been switched on once this year, and that was to check the contents of it's hard drive!!!) Comments, as invited by our EDITOR.... YES there are people out there using a BEEB emulator on a RISC-OS machine. There are also people out there using a RISC-OS machine to port 8-bit SW from other sources to 5{" discs and a BBC model B! Long live ACORN or is it to late?? ACORN ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, To: 999 (all members) From: D7X (Martin Hodgson) Subject: 8BS CD-ROM 1 continued. I was very interested to read John Crane's comments on 8BS 66. Firstly, running FDC on a PC (or card). It is typically DOS unfriendly. You run the programme and it just sits there - daring you to do something. Actually, you just type in the instructions as given by Chris, press RETURN, the discs start spinning and it does its job quite effectively. I have been persevering with trying to get the CD to work on my A5000, using ImageDFS. If you open the !ImageDFS directory (hold SHIFT and double click the mouse on it), you can load !Boot and !Run into Edit. The line :- Set Alias$@RunType`BBC Run .!Run %%*0 is what loads and runs ImageDFS when you click on a BBC image file. The `BBC needs to be changed to `FFD Likewise in the line :- Set File$Type`BBC DFSImage Note that ` is the underscore character. There is a similar line in !Run. Having done this, when you double click on one of Chris's image files, it loads and runs ImageDFS. The file type &FFD is the data file type, which RISC-OS assignes to any unknown file, e.g. those on the CD. However, ImagDFS then crashes out with the "general read file error". So, the file !RunImage, which is in BASIC, but crunched, contains five references to &BBC. I used a disc editor to change these to &FFD, to no avail. The CD files will load in OK if I copy to hard disc and filetype them &BBC. Consequently the problem must be in the module file ImageDFS (not !ImageDFS please note), or perhaps in the file LoadIDFS. These are not in BASIC, but appear to be compiled. Editing those files looks like being impossible. The only hope is to persuade Warm Silence Software to let somebody have the source code to amend it. On the matter of double-sided disc images, ImageDFS can create and read these itself. It will not read Chris's interleaved images, but presumably requires the sides concatonated together - as Chris has done for the ADFS disc images. ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, To: 999 (all members) From: D7X (Martin Hodgson) Subject: Disc Images PC / ACORN 8BS CD-ROM 1 IMAGE FILES on RISC-OS computers. Whilst the lack of Filetyping of the disc images on the CD can be overcome (copy the image to your hard disc and FilteType it &BBC) there seems to be no way you can read any of the Double-sided images. !ImageDFS is able to read the single-sided images, one side at a time, but will not read the interleaved double sided images. Chris has also provided the ADFS images in which the two sides are in the image file one after the other, non-interleaved, but ImageDFS will not read ADFS anyway. I have resorted to my PC and FDC.EXE to try and make similar DFS files, but find FDC.EXE will only produce interleaved disc images. On the Acorn machine, ImageDFS does produce double sided disc images, in which the two sides are non-interleaved. These are then useable by !BBCEm, but not by PcBBC on the PC because that will only read interleaved images. With non-interleaved images PcBBC reads the first side, but is not aware of the second side. CHris , in putting together the 8BS CD ROMs has in fact covered all the image fomats one might need, except for these DFS non-interleaved images. There is room on the CD for this, final (I think) format to be added. I will happily reconstitute the 63 discs from CD ROM 1 on my PC, then use !ImageDFs on the Acorn to make non-interleaved images. Perhaps Chris would then be kind enough to add them to the CD at some point in the future. ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, To: 999 (all members) From: CNC (Carlo Concari) Subject: Hello everybody! Hello there, I'm Carlo Concari from Italy, proud owner of an Olivetti Prodest PC 128S, aka a relabeled BBC Master Compact. I had it since I was 11, and learned a big deal about computers on that neat little machine. Unfortunately I never had access to telecom networks or BBSs back in the days. Living in a rural part of Italy we didn't even have a home telephone until 1989, go figure! All my programming was done solo, so I love to have a chance to distribute some of my efforts. Thanks Chris! I have a few contributions for this issue (bear with me please), but the piece of software I'm most proud of is a version of Tetris I wrote in 1991/1992. The game is utterly incomplete (no sound, no scoring, no levels) but playable. Have a good laugh with my English (I was just studying it in middle school at the time) and the graphics (I really can't draw). Also pass over the eyesore colour scheme if you can: the game was entirely developed on a green phosphor monitor on which it all seemed rather greenely pleasant anyway. All the best, - Carlo. ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, To: 999 (all members) From: CNC (Carlo Concari) Subject: SS ADFS copy protection Last year, fearing that 25 years old floppy discs could soon start failing, I've been making disc images of all my BBC floppies. The only ones I haven't been able to copy are the original Superior Software games, that employ a rather sophisticated copy protection scheme. I remember that a friend who owned an Amiga was the only one who was able to create fully working copies of those discs; don't know what copier software he used though. Finding no info on the Internet I dug out the disassemblers and debuggers I wrote circa 20 years ago and set out to investigate the copy protection scheme. To make a long story short, it turns out that Superior discs are split into three parts: * Several regular ADFS MFM tracks that contain boot files and loaders; * One special track which is checked by the copy protection scheme; * Many FM tracks carrying the games themselves; these tracks are read by the loaders once the special track is validated. The special track is a really tricky beast! The core of the protection scheme is that it is readable both in FM and MFM modes, and in each mode it sports four 512-byte sectors with logical IDs $F0 to $F3. Now, if you do the math, you will find that 4*512 bytes in MFM mode plus 4*512 bytes in FM mode take up more than a full track! Using the mighty Advanced Disc Investigator ROM I found out that the odd numbered sectors start halfway through the preceding even ones, thus saving considerable space. Incidentally, this wreaks havoc with the odd sectors which assume a bad CRC, which is required _to be bad_ by the loaders anyway! A simple patch to the loaders enabled me to copy the discs, but what I'd like to do for pure research spirit is write a piece of software to create such a track by direct access of the WD1770 FDC. I'm thinking about writing the four MFM sectors, then suddenly switching the controller to FM mode and writing the four FM sectors while the disc is spinning. Stay tuned, who knows, I could even find the time to really try this out! :) ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, To: 999 (all members) From: CNC (Carlo Concari) Subject: Model B games on the Compact I've been downloading tons of BBC games from the Internet lately, which are filling me with uncountable nostalgia. How I'd have loved to have access to all this stuff back in the good old days... Now that I have it I haven't got time to play. Ain't life unfair? Anyway, most of the 8 bit games for Acorn machines are coded for the BBC Micro, and I had some fun lately doing some reverse engineering and adapting them to my Master Compact clone. Most problems arise from random *DISC commands scattered around game loaders. The Compact has no tape interface, so MOS 5.10 disposed of *DISC which it considers a Bad command. Get rid of all the *DISC instances (some even found as OSCLI calls in machine code portions, as in Repton games) and chances are the game will run on the Master Compact. A couple of games had to be tweaked deeper though. Citadel kept freezing at the 'Welcome to...' message. It turned out that the game checks the type of machine it is running on using OSBYTE &00. This call returns 1 for the BBC, 3 for the Master 128, 5 for the Compact. The game was only checking for a Master 128, while the Compact was treated as a regular B causing the game to freeze. This is the relevant machine code from the file CITAL: 5720 LDX #&01 5722 LDA #&00 5724 JSR &FFF4 5727 TXA 5728 CMP #&03 572A BEQ &572D 572C RTS 572D JSR &5690 ;patch for Master The fix, as suggested by Richard Talbot-Watkins, is to change the BEQ at 572A into a BCS. Airwolf had to be tweaked as well. The game itself was working ok, but it had issues in the attract screens fonts, which it redefines. Master series machines, in fact, manage fonts quite differently from the BBC Micro. To solve the problem I wrote a patcher that needs to be applied once. It modifies the file Wolf1 to work on both classes of machines. The patcher is included in this issue.