AGON LIGHT- 'access denied' when saving BBC file

[Gelpack]

If I save a text version of a basic file on Agon Light using the same name it saves ok. However if it is a BBC File which is loaded, it will not save it unless you change the name.

I get 'access denied' but no other message, this appears to be common.

Anyone know the reason for this, or is it a bug. You can certainly do that on the BBC Micro

Cheers

[paulb]

Anyone know the reason for this, or is it a bug. You can certainly do that on the BBC Micro

Doesn't sound like particularly normal behaviour to me, but then I'm not particularly familiar with the Agon Light or related products. Does the Agon guy not have some forums where people can offer assistance? Troubleshooting such issues is hard enough on original Acorn hardware, given the software and hardware combinations, but at least many people here would know the issues. Stuff running on Agon or other retro remakes could be making their own rules up entirely.

[Gelpack]

I've seen a few people asking the question, but nobody I have seen answer it. I think it is probably because its keeping a file handle open when in edit mode, but thats a guess. But then it does allows you to save the Text Based Basic i.e. .basicFile.txt. with no problem. Just the *.BBC file types that exhibit this.

[paulb]

Just the *.BBC file types that exhibit this.

It reminds me of the way that executable files can be "locked" in certain operating systems because they are in active use. But the developers of the Agon system software would have to explain themselves here, I think. I looked for a forum but only found this:

"Developpers forum for the Agon Light"

It seems that the Agon guy does a lot of social media stuff, alongside his unusable Web site, so maybe he expects people to be "on the socials". Unfortunate, really.

[scruss]

Discussion is likely on Discord, and thus completely hidden from the general internet. There's a link to a Discord invitation here: damn_pastor comments on Agon Discord. The main Agon dude seems to have moved on to promoting a newer board, so maybe Olimex and others have to carry the weight.

The Agon dude really likes his trademarks, doesn't he? For something that's mostly a mashup of other people's work, he's going heavy on the IP. I don't wanna know how it ends when Intel notices their Quark trademark on his software

[Gelpack]

Thanks for the reply.

As a quark is a type of elementary particle and a fundamental constituent of matter, I'm not entirely sure if that is trade-mark-able , but you could well have a point.

[Gelpack]

Just the *.BBC file types that exhibit this.

"Developpers forum for the Agon Light"

It seems that the Agon guy does a lot of social media stuff, alongside his unusable Web site, so maybe he expects people to be "on the socials". Unfortunate, really.

That does not seem to have any take-up. I might load the latest version of the firmware and see if there is any update on this.

I really feel that what he has accomplished is actually very good in terms of his aims. The general principle is to provide a low price point 8 bit machine which competes and exceeds any other 8 bit computer in speed and by all account this has been successful in the benchmarks I have seen. The ethos behind it also respects the expectation that someone should be able to understand everything on that computer just like back in the day which is seldom the case now as you cant get circuit diagrams etc, are unlikely to get listings for the operating system anymore on say a major laptop, as well as being able to source the parts as they are still in production unlike many chips on old retro computers.

We'll see I guess.

[paulb]

That does not seem to have any take-up. I might load the latest version of the firmware and see if there is any update on this.

Going via Olimex's product page, I found the Agon Light Wiki. Browsing that wiki, I found a link to the BBC BASIC (Z80) for the Agon Light documentation. I'm not sure where your particular issue might be described, though.

I could imagine you ending up filing an issue against the appropriate component in GitHub if you can't get the help you need.

[Gelpack]

Hi Paul,

Yeah, I was aware of all that documentation including the BBC differences file and found no reference to it. My belief is that this should work and simply does not, so tomorrow I am going to try and find the MOS release notes *after my particular version and try and see if there is mention on an update.

Thanks for your help.

[jgharston]

Is the code that LOAD uses doing openin/read/close ? It could be that it's omitting the close (or using the wrong handle), so when you try to overwrite it the subsystem refuses.

[Gelpack]

Is the code that LOAD uses doing openin/read/close ? It could be that it's omitting the close (or using the wrong handle), so when you try to overwrite it the subsystem refuses.

I do not know at this point, but I will take a look at the release notes for any later versions shortly

[Gelpack]

Update
---------

I cannot find a reference to this anywhere MOS or BBC Basic Versions. even though I did see a reference to it being a limitation of the MOS rather than the BBC BASIC. Not the end of the world, but really really irritating. I suppose some might say, it is a safeguard from accidental updates, in other words you will allways have the original even though it could be deleted manually, but this does not explain why a txt file can be save over with the same name.

I think I am going to have to drop this as I have other things to be getting on with.

Thanks for all your comments and help.

[jgharston]

It will be nothing to do with BASIC - all BASIC does is make a call to the host's file load code. It will be nothing to do with the MOS it's running on - all the MOS does is pass the call on to the filing system. It will be down to how the filing (sub)system implements the LOAD call (OSFILE 255 on Acorn systems, fopen()/read()/fclose() on Unix systems, FOPEN/FREAD/FCLOSE on CP/M, etc, etc.)

Tracking through the Agon MOS code we get to mos_load() which has:

Code: Select all

	fr = f_open(&fil, filename, FA_READ);
	if(fr == FR_OK) {
		fSize = f_size(&fil);
		fr = f_read(&fil, (void *)address, fSize, &br);		
	}
	f_close(&fil);	
	return fr;

For a start, that f_close(&fil); should be within the if(), as it's trying to close a non-existant handle if the open failed. I haven't checked, but I bet mos_save() has the same problem.

This isn't using standard fopen() calls, it is using its own file code, so follow the rabbit down into the f_open() code. It will be something within agon_mos.zip -> src_fatfs -> ff.c

To confirm the initial reported problem, confirm it exactly. Check what this does, if the issue is as reported it should abort with Access denied at line 20.
10 *SAVE FRED 0+1
20 *SAVE FRED 0+1
30 *SAVE FRED 0+1

[Gelpack]

It will be nothing to do with BASIC - all BASIC does is make a call to the host's file load code.

.....

To confirm the initial reported problem, confirm it exactly. Check what this does, if the issue is as reported it should abort with Access denied at line 20.
10 *SAVE FRED 0+1
20 *SAVE FRED 0+1
30 *SAVE FRED 0+1

Thanks John

I never said it was a fault of basic. But it is only the basic file that has a problem with saving, as. .TXT files save over themselves just fine. As I said I am going to leave it for now as I have more pressing things to deal with, but I appreciate your reply.

Cheers

[jgharston]

Thanks John

Who?

[Gelpack]

Thanks John

Who?

Apologies. for some reason my brain linked the J to John.