What will stop ADI2 accessing DFS Track 0?

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flaxcottage
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What will stop ADI2 accessing DFS Track 0?

Post by flaxcottage » Thu Oct 11, 2018 8:50 pm

This is a weird one. I have a protected disc which catalogues and runs correctly but when I try to examine the catalogue sector, Track 0 Sector 0, only garbage appears in the edit window of ADI2.

If I scan the disc, Track 0 is reported as having no sectors. This is not the case as !BOOT runs perfectly and so the catalogue sectors must be being read.

ADI2 reports the formatting of all the other tracks correctly.

Another disc, with the same protection mechanism, does not have this effect and Track 0 scans correctly.

Any ideas?
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Re: What will stop ADI2 accessing DFS Track 0?

Post by danielj » Thu Oct 11, 2018 8:53 pm

No :( but if you bring it along next month I'll bring the kryothingy along and we can try and pick it apart?!

d.

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Re: What will stop ADI2 accessing DFS Track 0?

Post by flaxcottage » Thu Oct 11, 2018 9:29 pm

Thanks, Daniel, I'll do that.

I have just got a Kryothingy myself but it is being a very silly-thingy to get set up. I have tried 5 PCs and only a very odd and niche Samsung Q1 running XP managed to install the drivers and run the software without errors. Vista and Windows 7 won't touch it! :(

Anyway Kryo did manage to archive the disk - or so it said. :lol:
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Re: What will stop ADI2 accessing DFS Track 0?

Post by danielj » Fri Oct 12, 2018 5:05 am

The driver installs weirdly in windows 7 and 10. Find the Bosa driver in devices (USB serial I think) and then update, have disk, point at the kryoflux driver directory.

d.

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Re: What will stop ADI2 accessing DFS Track 0?

Post by duikkie » Fri Oct 12, 2018 6:01 am

do you really asking the programmer to write down how this is done ?

it is a sort of game :) , there are people who dig in a program like ADI2 to find a weak spot
then use it :)

i personaly know a few tricks that i have not seen there yet , and i will not tell :)
i do not know if this disc use something like i found out.
it is the people on this form to show how to unprotect :lol:

i have wrote this some time track 0 is not always on the place on the disc surface where
it normaly is , if a system can not find track 0 it skips 255 times ( by 8271)
i do not know if this is in this case true , but it can be ?

maybe other hint it is IBM format , that trick i have not seen that here yet #-o

if you finds out please tell [-o< , i really want to know what out of the box thinking
is used :)

flaxcottage wrote:
Thu Oct 11, 2018 8:50 pm
This is a weird one. I have a protected disc which catalogues and runs correctly but when I try to examine the catalogue sector, Track 0 Sector 0, only garbage appears in the edit window of ADI2.

If I scan the disc, Track 0 is reported as having no sectors. This is not the case as !BOOT runs perfectly and so the catalogue sectors must be being read.

ADI2 reports the formatting of all the other tracks correctly.

Another disc, with the same protection mechanism, does not have this effect and Track 0 scans correctly.

Any ideas?
Last edited by duikkie on Fri Oct 12, 2018 6:02 am, edited 1 time in total.

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Re: What will stop ADI2 accessing DFS Track 0?

Post by billcarr2005 » Fri Oct 12, 2018 6:46 am

Most likely a software (ADI2) error, unless the disk is "flaky" in which case it might not be "seeing" track 0 within it's threshold to read it.
If the DFS is able to read the necessary sectors then they have to be strictly vanilla...
What disk is it?
Did you try that sector dump program I sent a while ago?
Last edited by billcarr2005 on Fri Oct 12, 2018 6:47 am, edited 1 time in total.

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Re: What will stop ADI2 accessing DFS Track 0?

Post by flaxcottage » Fri Oct 12, 2018 9:13 am

The disk is Dragon mix.

Yes I did do that sector read and that shows everything as it should be. I tried several different floppy drives in case it was an alignment issue. They all ran the disk, catalogued the disk but ADI2 would not scan Track 0. I even tried different computers.

I wrote my own sector reader but that only loaded garbage.

Alligator mix, which uses the same protection scans perfectly and my sector reader works as well.

I'll dig out a copy of ADI version 1 and see if that can read the track. Then there is Disc Doctor on my 8271 machine ...
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Re: What will stop ADI2 accessing DFS Track 0?

Post by duikkie » Fri Oct 12, 2018 2:47 pm

most of the protection disc are tested by discdocter and exmon1 , that what i did in the old days :)
later came exmon2 and adi or was it something with copydisk III

i think that track 0 is not at track 0 , but somewhere in the middle of the disc.
did you scan the whole disc for id track numbers ? even outside track 80 ?

work the disc with all dfs and 8271 and 1770 ?
flaxcottage wrote:
Fri Oct 12, 2018 9:13 am
The disk is Dragon mix.

Yes I did do that sector read and that shows everything as it should be. I tried several different floppy drives in case it was an alignment issue. They all ran the disk, catalogued the disk but ADI2 would not scan Track 0. I even tried different computers.

I wrote my own sector reader but that only loaded garbage.

Alligator mix, which uses the same protection scans perfectly and my sector reader works as well.

I'll dig out a copy of ADI version 1 and see if that can read the track. Then there is Disc Doctor on my 8271 machine ...

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Re: What will stop ADI2 accessing DFS Track 0?

Post by billcarr2005 » Fri Oct 12, 2018 3:25 pm

flaxcottage wrote:
Fri Oct 12, 2018 9:13 am
The disk is Dragon mix.
Did you run out of disks to archive, that you're checking over old titles? :o
flaxcottage wrote:
Fri Oct 12, 2018 9:13 am
I wrote my own sector reader but that only loaded garbage.
What code was your own sector reader based on? The one I supplied was ripped from FSD maker which in turn was borrowed from Enigma Disc Imager.
flaxcottage wrote:
Fri Oct 12, 2018 9:13 am
Alligator mix, which uses the same protection scans perfectly and my sector reader works as well.
I think I've seen two variants of protection on these disks... (although I'm not sure it's devious protection at work here)
duikkie wrote:
Fri Oct 12, 2018 6:01 am
i have wrote this some time track 0 is not always on the place on the disc surface where
it normaly is , if a system can not find track 0 it skips 255 times ( by 8271)
I thought that it only steps forward 2 tracks, if the logical track ID doesn't match the physical, but can't remember where / when I read it exactly... possibly on a 8271 data sheet... was related to the FSD image of Krakout I had.

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Re: What will stop ADI2 accessing DFS Track 0?

Post by flaxcottage » Fri Oct 12, 2018 3:36 pm

billcarr2005 wrote:
Fri Oct 12, 2018 3:25 pm
flaxcottage wrote:
Fri Oct 12, 2018 9:13 am
The disk is Dragon mix.
Did you run out of disks to archive, that you're checking over old titles? :o
flaxcottage wrote:
Fri Oct 12, 2018 9:13 am
I wrote my own sector reader but that only loaded garbage.
What code was your own sector reader based on? The one I supplied was ripped from FSD maker which in turn was borrowed from Enigma Disc Imager.
Ha ha! No, I got Dragon Mix out to Kryoflux to see if it could copy the disc. Unfortunately Kryoflux would not work on any of my PCs. It seems they are too retro. They only go up to Windows 7 and that is being phased out by Kryoflux. I just thought I'd have a look for old times sake and then discovered this. :lol:

My code was written in BASIC. It works OK for unprotected tracks and sectors.

Doesn't DFS specify that the catalogue is always on Track 0 Sectors 0 and 1? Seek 0 should always find the catalogue, I thought.
- John
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Re: What will stop ADI2 accessing DFS Track 0?

Post by 1024MAK » Fri Oct 12, 2018 4:57 pm

Yeah, but the system reads the disk to locate that logical position. Sector and track data is stored on the disk as part of the format. The drive is a dumb device (and on soft sectored disks) there is only a single physical index pulse and on some drives, a single “track zero” signal. All the clever stuff is done by the disk drive controller and the disk filing system working together.

So if a non-standard format is being used, but still makes sense to the disk drive controller, and to the disk filing system, the system can still read the disk.

Mark

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Re: What will stop ADI2 accessing DFS Track 0?

Post by duikkie » Sat Oct 13, 2018 3:27 am

the intresse thing is what happens if the disk drive controller can not make sense and it is not a error :) , a disc drive controller trys a lot ( the 8271) before it report an error. then comes the dfs mostly programmed for BBC standaard discs format. and is not that good if something is different. how to handle then :)

most protected things are based on things that are in the datasheet or error handling or bugs.

1024MAK wrote:
Fri Oct 12, 2018 4:57 pm
Yeah, but the system reads the disk to locate that logical position. Sector and track data is stored on the disk as part of the format. The drive is a dumb device (and on soft sectored disks) there is only a single physical index pulse and on some drives, a single “track zero” signal. All the clever stuff is done by the disk drive controller and the disk filing system working together.

So if a non-standard format is being used, but still makes sense to the disk drive controller, and to the disk filing system, the system can still read the disk.

Mark

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Re: What will stop ADI2 accessing DFS Track 0?

Post by CMcDougall » Sun Oct 14, 2018 8:14 pm

viewtopic.php?f=2&t=15728#p215581
did you try my original v121 from this thread a few weeks ago??

I had a disc that done similar with UPURS5r :shock:
in the end I just copied it to SD card with the MMFS prog DTOM :)

still a weird one though :?
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Re: What will stop ADI2 accessing DFS Track 0?

Post by jgharston » Sun Oct 14, 2018 8:26 pm

duikkie wrote:
Sat Oct 13, 2018 3:27 am
the intresse thing is what happens if the disk drive controller can not make sense and it is not a error :) , a disc drive controller trys a lot ( the 8271) before it report an error. then comes the dfs mostly programmed for BBC standaard discs format. and is not that good if something is different. how to handle then :)
The 8271 doesn't retry, it only attempts once. The DFS disk access code retries, attempting up to ten times. Or, in DFS 1.21/1.22 patched for 3.5" drives, attempts an infinite number of times if the failure was "drive not ready".

Code: Select all

$ bbcbasic
PDP11 BBC BASIC IV Version 0.25
(C) Copyright J.G.Harston 1989,2005-2015
>_

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Re: What will stop ADI2 accessing DFS Track 0?

Post by flaxcottage » Sun Oct 14, 2018 8:47 pm

CMcDougall wrote:
Sun Oct 14, 2018 8:14 pm
viewtopic.php?f=2&t=15728#p215581
did you try my original v121 from this thread a few weeks ago??

I had a disc that done similar with UPURS5r :shock:
in the end I just copied it to SD card with the MMFS prog DTOM :)

still a weird one though :?
I'll give that a go, Col, thanks. I also have ADI version 1.0 to try as well. I have a Master write-protected SWR on my machine so no need to blow into an EPROM until I can see if it works.

What is even weirder is that once in a while ADI does read the track. Once only so I can't do anything but it does read it. :?
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Re: What will stop ADI2 accessing DFS Track 0?

Post by CMcDougall » Mon Oct 15, 2018 8:56 pm

another thing to try John is to take out MMC rom & unplug card from user port, gave me more success.
also use a normal beeb: 8271fdc & dfs1.20, as even one of my 1770fdc beebs gave different results :o
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Re: What will stop ADI2 accessing DFS Track 0?

Post by flaxcottage » Tue Oct 16, 2018 8:19 am

I don't use the MMC system on my Master - I use a datacentre instead.

Tried the 8271 route cos I thought that may show a difference but the result was just the same. Even Disc Doctor struggled to read track 0 as well.
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Re: What will stop ADI2 accessing DFS Track 0?

Post by duikkie » Tue Oct 16, 2018 11:52 am

oke what did you try so far ?

try to read track 0 ID markers , with a simple machine code program in the advanced disc book
try this with more then 10 sectors , maybe 20 or 50 ?
preform a seek 0 , before you read id numbers on track 0
maybe you hear the arm moving ? if not then track 0 is track 0 :)
maybe only sector 0 and 1 are formatted at track 0 ?


flaxcottage wrote:
Tue Oct 16, 2018 8:19 am
I don't use the MMC system on my Master - I use a datacentre instead.

Tried the 8271 route cos I thought that may show a difference but the result was just the same. Even Disc Doctor struggled to read track 0 as well.

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