Search found 57 matches

by jay
Sun Sep 27, 2020 7:33 pm
Forum: 8-bit acorn emulators
Topic: Floppy Image Formats
Replies: 23
Views: 2105

Re: Floppy Image Formats

- HFE is well supported by beebjit. (Pretty much all original protected discs work.) AIUI HFE supports having a different format for track 0 and the rest of the disc. How does beebjit handle the case where we have an FM disc and some software issues a format command for track 10, in MFM mode? I sup...
by jay
Sun Sep 27, 2020 7:26 pm
Forum: 8-bit acorn emulators
Topic: [B-EM] Is there anything unusual in the way Watford DFS detects write-protected discs?
Replies: 15
Views: 607

Re: [B-EM] Is there anything unusual in the way Watford DFS detects write-protected discs?

I've fixed the CRC bug. The cause was incorrect handling of HFEv3 opcode arguments. I sent a PR with the fix in, and some other tidying-up.

Still not tested:
- two-sided images
- MFM images
by jay
Sat Sep 26, 2020 10:54 am
Forum: 8-bit acorn emulators
Topic: [B-EM] Is there anything unusual in the way Watford DFS detects write-protected discs?
Replies: 15
Views: 607

Re: [B-EM] Is there anything unusual in the way Watford DFS detects write-protected discs?

I have pushed some commits to master which I believe solve the Watford write protect issue along with some others. That seems a lot better, thanks. I notice that in Watford DFS, *FORM80 hangs. It looks like fdc_writeprotect gets called and the hfe driver goes to idle mode and the motor gets turned ...
by jay
Fri Sep 25, 2020 6:11 pm
Forum: 8-bit acorn emulators
Topic: [B-EM] Is there anything unusual in the way Watford DFS detects write-protected discs?
Replies: 15
Views: 607

Re: [B-EM] Is there anything unusual in the way Watford DFS detects write-protected discs?

Here is a test file I have been using. If we can find HFE files (especially single-density files, for now) with which these patches don't work well, please link them here or attach them, and I will investigate.
by jay
Thu Sep 24, 2020 11:04 pm
Forum: 8-bit acorn emulators
Topic: [B-EM] Is there anything unusual in the way Watford DFS detects write-protected discs?
Replies: 15
Views: 607

Re: [B-EM] Is there anything unusual in the way Watford DFS detects write-protected discs?

It may be timing. Watford DDFS swaps NMI routine, sometimes, I think, in what should be an inter-sector gap so if it gets a result too soon it can miss it. You may need to experiment with fdc_time. Interestingly, wd770_writeprotect() sets fdc_time while i8271_writeprotect does not. But I cannot fin...
by jay
Thu Sep 24, 2020 10:56 pm
Forum: 8-bit acorn emulators
Topic: Floppy Image Formats
Replies: 23
Views: 2105

Re: Floppy Image Formats

HFE is where I think emulators should focus for their "more capable" floppy format: - HFE is well supported by Gotek + FlashFloppy. - HFE is well supported by beebjit. (Pretty much all original protected discs work.) ... I've made a stab at HFE suppport for B-EM here: https://github.com/stardot/b-e...
by jay
Thu Sep 24, 2020 9:00 am
Forum: 8-bit acorn emulators
Topic: [B-EM] Is there anything unusual in the way Watford DFS detects write-protected discs?
Replies: 15
Views: 607

Re: [B-EM] Is there anything unusual in the way Watford DFS detects write-protected discs?

I think it's likely that my disc-media driver is interacting incorrectly with the I/O implementation of B-EM. The actual functionality of the hardware FDC is split, in B-EM, between the i827/1770 emulation code and the media driver. For example, the FDC drivers in b-em only ever see fully-decoded by...
by jay
Thu Sep 24, 2020 12:18 am
Forum: 8-bit acorn emulators
Topic: [B-EM] Is there anything unusual in the way Watford DFS detects write-protected discs?
Replies: 15
Views: 607

[B-EM] Is there anything unusual in the way Watford DFS detects write-protected discs?

I've been working on a new module for B-EM (sorry, I cannot share the code yet) which implements a new floppy file format. It's read-only so it needs to make write-sector and format operations fail. It does this by setting writeprot[d] and calling fdc_writeprot() from myformat_poll() when it's calle...
by jay
Tue Aug 04, 2020 9:49 am
Forum: 8-bit acorn emulators
Topic: Emulator support for DD HFE files?
Replies: 10
Views: 766

Re: Emulator support for DD HFE files?

Do we have any idea why it's desirable to use DISABLE_FLOPPYMODE for the Amiga or ST emulations? It's not, but wouldn't they argue for the default to be AMIGA_DD_FLOPPYMODE or ATARIST_DD_FLOPPYMODE? I don't know what those do, so I don't know. But my only real criterion here is that, whatever HFE f...
by jay
Mon Aug 03, 2020 10:41 am
Forum: 8-bit acorn emulators
Topic: Emulator support for DD HFE files?
Replies: 10
Views: 766

Re: Emulator support for DD HFE files?

Interestingly if by hand I change the floppy interface mode byte in the HFE header from 254 ("DISABLE_FLOPPYMODE") to 7 ("GENERIC_SHUGART_DD_FLOPPYMODE") things seem to work. I haven't yet played with saving to HFE but this looks like a limitation. By default MAME will create a HFE image with inter...
by jay
Mon Aug 03, 2020 10:37 am
Forum: 8-bit acorn emulators
Topic: Emulator support for DD HFE files?
Replies: 10
Views: 766

Re: Emulator support for DD HFE files?

I have now updated beebtools to support double-density floppy images in the HFE (versions 1 and 3) and HxC MFM formats. The latter format is more usually used for Atari ST floppy images but is supported by MAME. Both of these formats are capable of representing various copy-protection schemes but be...
by jay
Sun Jul 19, 2020 4:41 am
Forum: 8-bit acorn emulators
Topic: Choosing a copyright license for DFS image tool / BBC BASIC de-tokenizer
Replies: 21
Views: 1281

Re: Choosing a copyright license for DFS image tool / BBC BASIC de-tokenizer

I ended up choosing the Apache 2 license. Reasons: Apache 2 licensed code can be incorporated into GPL (v3) code bases. It's non-copyleft (i.e. "non-viral"), an idea I wanted to try out (all my other code is GPLed). It explicitly states the expectation that contributors are contributing code under t...
by jay
Sat Jul 18, 2020 4:07 am
Forum: 8-bit acorn emulators
Topic: Emulator support for DD HFE files?
Replies: 10
Views: 766

Re: Emulator support for DD HFE files?

I haven't yet played with saving to HFE but this looks like a limitation. By default MAME will create a HFE image with interface mode DISABLE_FLOPPYMODE whereas setting it to GENERIC_SHUGART_DD_FLOPPYMODE is probably a better choice, but then there'd be complaints from the Amiga/ST/etc. crowd. A be...
by jay
Sat Jul 18, 2020 4:05 am
Forum: 8-bit acorn emulators
Topic: Emulator support for DD HFE files?
Replies: 10
Views: 766

Re: Emulator support for DD HFE files?

I haven't yet played with saving to HFE but this looks like a limitation. By default MAME will create a HFE image with interface mode DISABLE_FLOPPYMODE whereas setting it to GENERIC_SHUGART_DD_FLOPPYMODE is probably a better choice, but then there'd be complaints from the Amiga/ST/etc. crowd. A be...
by jay
Fri Jul 17, 2020 11:22 pm
Forum: 8-bit acorn emulators
Topic: Emulator support for DD HFE files?
Replies: 10
Views: 766

Re: Emulator support for DD HFE files?

MAME - haven't tried it, though I understand it supports HFE I just got around to trying this. The default install of MAME (that's in Debian stable) didn't support HFE so I built from github source. Starting the emulator with mame64 bbcb -window -fdc weddb3 I was able to use the File Manager to cre...
by jay
Fri Jul 17, 2020 8:00 pm
Forum: programming
Topic: Which keywords were introduced the various BBC BASIC versions?
Replies: 2
Views: 310

Re: Which keywords were introduced the various BBC BASIC versions?

Is there a breakdown anywhere of the keywords supported in each version of BBC BASIC? http://mdfs.net/Docs/Comp/BBCBasic/Tokens Yes, I've read it carefully. It lumps all versions of BBC BASIC for any given CPU together. So it doesn't distinguish (for example) when TIME$ was introduced (which was, I...
by jay
Fri Jul 17, 2020 7:47 pm
Forum: 8-bit acorn software: other
Topic: Name of the CRC from the Advanced User Guide?
Replies: 6
Views: 578

Re: Name of the CRC from the Advanced User Guide?

Just to make sure I understand what's happening here, could somebody post for me the CRC field from a standard archive ".inf" file corresponding to an entirely empty file? That will confirm that we really do need to iniitalise the CRC computaton with &0000 and confirm the order in which the output b...
by jay
Fri Jul 17, 2020 12:43 pm
Forum: programming
Topic: Which keywords were introduced the various BBC BASIC versions?
Replies: 2
Views: 310

Which keywords were introduced the various BBC BASIC versions?

There is an extensive list of BBC BASIC versions with dates of introduction, compiled - I assume - by J. G. Harston. (Thanks for doing it!) Is there a breakdown anywhere of the keywords supported in each version of BBC BASIC? I assume the grouping of BBC BASIC implementations is something like a "fa...
by jay
Fri Jul 17, 2020 10:32 am
Forum: 8-bit acorn emulators
Topic: Floppy Image Formats
Replies: 23
Views: 2105

Re: Floppy Image Formats

Anyway the real adoption problem with stream or cells based formats (SCP, KF RAW, HFE...) are not the formats documentations or whatever but the fact that most emulators don't really emulate the FDC. beebjit and MAME do. I'd be surprised if there were not others. Yeah, Clock Signal too — the sector...
by jay
Fri Jul 17, 2020 10:21 am
Forum: programming
Topic: BBC Basic Keywords - Mac updates, questions
Replies: 13
Views: 882

Re: BBC Basic Keywords - Mac updates, questions

Thanks for the suggestions. I've updated the code with this effect:
bbcbasic.pdf
(57.42 KiB) Downloaded 16 times
by jay
Thu Jul 16, 2020 11:48 pm
Forum: 8-bit acorn emulators
Topic: Floppy Image Formats
Replies: 23
Views: 2105

Re: Floppy Image Formats

Jeff_HxC2001 wrote:
Thu Jul 16, 2020 10:58 pm
Anyway the real adoption problem with stream or cells based formats (SCP, KF RAW, HFE...) are not the formats documentations or whatever but the fact that most emulators don't really emulate the FDC.
beebjit and MAME do. I'd be surprised if there were not others.
by jay
Thu Jul 16, 2020 11:44 pm
Forum: 8-bit acorn emulators
Topic: b-em & interleaved double-density files
Replies: 14
Views: 1047

Re: b-em & interleaved double-density files

Regarding sdd and ddd, which are intended for double density images: .sdd is one side, 16 or 18 sectors per track. The geometry is given by the file size: 1 x 40 x 16 (160K), 1 x 40 x 18 (180K), 1 x 80 x 16 (320K), 1 x 80 x 18 (360K) .ddd is two sides, side-interleaved, 16 or 18 sectors per track. ...
by jay
Thu Jul 16, 2020 11:26 pm
Forum: programming
Topic: BBC Basic Keywords - Mac updates, questions
Replies: 13
Views: 882

Re: BBC Basic Keywords - Mac updates, questions

I've finally made an open-source release of the code I was working on when I started this thread. It has some DFS functionality, but relevantly to this thread, it reads BBC BASIC program files and converts them to ASCII. It covers, I believe, nearly all published BBC BASIC implementations - 6502 (e....
by jay
Thu Jul 16, 2020 7:49 pm
Forum: 8-bit acorn software: other
Topic: Name of the CRC from the Advanced User Guide?
Replies: 6
Views: 578

Re: Name of the CRC from the Advanced User Guide?

cmorley wrote:
Thu Jul 16, 2020 7:24 am
It is on the wikipedia list... it is the 16 bit CRC with normal polynomial 0x1021.
Thanks. AIUI, it's initialised with &0000 not &FFFF, so it's not the CCITT CRC-16. Closer to the XMODEM CRC16, though perhaps with a permutation of the byte/bit ordering.
by jay
Thu Jul 16, 2020 7:11 am
Forum: 8-bit acorn software: other
Topic: Name of the CRC from the Advanced User Guide?
Replies: 6
Views: 578

Name of the CRC from the Advanced User Guide?

P. 348 of the BBC Micro Advanced User Guide describes the CRC implementation used by the tape filing system (and thus, by "Standard Archive Format" .INF files). I didn't spot this in https://en.wikipedia.org/wiki/Cyclic_redundancy_check or in http://reveng.sourceforge.net/crc-catalogue/16.htm; does ...
by jay
Wed Jul 15, 2020 9:53 pm
Forum: 8-bit acorn emulators
Topic: Floppy Image Formats
Replies: 23
Views: 2105

Re: Floppy Image Formats

[FYI the HFE file format is the H xC F loppy E mulator file format. It was specified 12 years ago for the SD HxC Floppy Emulators (No point at all with Gotek at this point). The HFE v3 is an experimental format evolution introduced by the HxC firmware for Gotek in 2017 ( See release notes ). But th...
by jay
Wed Jul 15, 2020 9:24 am
Forum: 8-bit acorn emulators
Topic: Floppy Image Formats
Replies: 23
Views: 2105

Re: Floppy Image Formats

Anyway, that says it is revision 1.1. Is that the latest, other than 3, i.e. was there no revision 2? Nothing after v1.1 is documented, and the only there thing I've heard of people using is v3. So my guess would be that there's no revision 2. HFE revision 2 seems to exist, at least in the HxC sour...
by jay
Sun Jul 12, 2020 9:53 am
Forum: 8-bit acorn emulators
Topic: Emulator support for DD HFE files?
Replies: 10
Views: 766

Emulator support for DD HFE files?

I'm trying to find a Beeb emulator - working on Linux - which supports double-density HFE files and is usable with DFS-family file systems. My understanding of the current situation is: B-EM - doesn't support HFE beebjit - supports HFE and the WD1770, but - I suspect - not Watford DDFS MAME - haven'...
by jay
Sat Jul 11, 2020 6:17 pm
Forum: 8-bit acorn software: other
Topic: Repository of HFE-format non-protected disc images?
Replies: 1
Views: 234

Repository of HFE-format non-protected disc images?

I'm working on software support for HFE images. Is there a repository anywhere of non-copy-protected HFE images for DFS? I'l like to restrict myself to non copy-protected images for now, as I don't want to confuse "my software doesn't work" with "this disc is copy-protected and you're not supposed t...

Go to advanced search