Help wanted: Imaging a protected disk

A forum about Atari protected floppy disks analysis, preservation, emulation, tools

Moderators: DrCoolZic, Brume

AtariZoll
Fuji Shaped Bastard
Fuji Shaped Bastard
Posts: 2904
Joined: Mon Feb 20, 2012 4:42 pm
Contact:

Re: Help wanted: Imaging a protected disk

Postby AtariZoll » Thu Jan 28, 2016 7:55 pm

I'm done with this thread and *silver . Someone should just delete all his posts here, because they are completely unnecessary, not help anything - he just wants to show how he smart and experienced is, while writes huge stupidities and nonsenses - over and over again. No respect for such people. I respect facts and constructive posts.
Negative feedback has usually positive effect.

User avatar
exxos
Hardware Guru
Hardware Guru
Posts: 4933
Joined: Fri Mar 28, 2003 8:36 pm
Location: England
Contact:

Re: Help wanted: Imaging a protected disk

Postby exxos » Thu Jan 28, 2016 8:16 pm

I think its got a bit confusing here what people are referring to here. I'm having trouble following it, though I confess I don't know much about the 1772 internals. What I see here, that the 1771 is capable of 12 sectors or even 14, FcopyII (IIRC) has those options but disabled, because it needs 12mhz on the 1772 to work.

As for if 12 sectors is possible with a 8mhz machine, I really can't say either way. I would assume not. I don't know every hack under the sun. This is similar issue with needing 16mhz on the 1772 to write 1.44 disks. You need the faster clock to increase the amount of sectors on the floppy. Twice the clock = half the delay = double sector count.

I think there might be some confusion somewhere over 12 sectors being the limit, Though this is (if I read correctly whats being said ) a limit on 720K floppies. The medium itself wasn't designed to take those sector densities. There was enough people back in the day worrying over 11 sectors, nevermind 12 or more. So a 1.44 floppy should be used for higher sector counts, I don't know the limit, though I've formatted up to 22 sectors.
4MB STFM 1.44 FD- VELOCE+ 020 STE - Falcon 030 CT60 - Atari 2600 - Atari 7800 - Gigafile - SD Floppy Emulator - PeST - various clutter

http://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
http://www.exxoshost.co.uk/atari/last/storenew/ - All my hardware mods for sale - Please help support by making a purchase.
http://ataristeven.exxoshost.co.uk/Steem.htm Latest Steem Emulator

AtariZoll
Fuji Shaped Bastard
Fuji Shaped Bastard
Posts: 2904
Joined: Mon Feb 20, 2012 4:42 pm
Contact:

Re: Help wanted: Imaging a protected disk

Postby AtariZoll » Thu Jan 28, 2016 9:42 pm

All it is clear, and there is people who knows much more than me about floppies. But you will not see them wasting time here. Whole science is that there is tolerance in density, what FDC chip can process. So, you can do 12 sectors/track with higher density than normal. This is only way. There is crack of Maupiti Island, with 12 sectors/track format. Supplied is formatting util for that. But it never worked for me, and I'm sure never for most.
Cracker just had slower floppy drive, and that's why he could format and write it. We may say that for DD 11 sector/track is limit if not go in higher density. On Atari. On PC it is 10 s/tr because it's FDC is slower. Medium can take of course little higher density - 10% is really not much for ... And top of stupidity was saying that home computers can not write quality something like 10% + density in DD mode. My Atari 520ST could write reliable 20 sectors/track with 100%+ density - what is called HD mode - with it's original FDC chip - just supplied it with 16 MHz . Chips are designed with lot of reserve.
Negative feedback has usually positive effect.

User avatar
dlfrsilver
Atari God
Atari God
Posts: 1419
Joined: Mon Jan 31, 2005 1:41 am
Contact:

Re: Help wanted: Imaging a protected disk

Postby dlfrsilver » Thu Jan 28, 2016 10:09 pm

exxos wrote:I think its got a bit confusing here what people are referring to here. I'm having trouble following it, though I confess I don't know much about the 1772 internals. What I see here, that the 1771 is capable of 12 sectors or even 14, FcopyII (IIRC) has those options but disabled, because it needs 12mhz on the 1772 to work.


The 1772 can read 70 sectors :) The Starter-70 sectors is a proof of that.

As for if 12 sectors is possible with a 8mhz machine, I really can't say either way. I would assume not. I don't know every hack under the sun. This is similar issue with needing 16mhz on the 1772 to write 1.44 disks. You need the faster clock to increase the amount of sectors on the floppy. Twice the clock = half the delay = double sector count.


It can be done, but it's not reliable.

I think there might be some confusion somewhere over 12 sectors being the limit, Though this is (if I read correctly whats being said ) a limit on 720K floppies.


12 sectors for a storage format, where each sectors contains data, yes that's the limit. However, for any protection track, you can have XX sectors fake or empty.

The medium itself wasn't designed to take those sector densities. There was enough people back in the day worrying over 11 sectors, nevermind 12 or more. So a 1.44 floppy should be used for higher sector counts, I don't know the limit, though I've formatted up to 22 sectors.


In fact the double density disks have no problem with the 11 sectors or even 12 sectors. The question is, what machine is used to written them.
If you use a machine or a board with a custom FDC, you can write with precision, and accurately this format. With a standard computer and a standard FDC, it's unreliable over the years.
Now SPS France representative since the 19th of June 2014. Proud to be an SPS member !

AtariZoll
Fuji Shaped Bastard
Fuji Shaped Bastard
Posts: 2904
Joined: Mon Feb 20, 2012 4:42 pm
Contact:

Re: Help wanted: Imaging a protected disk

Postby AtariZoll » Thu Jan 28, 2016 11:04 pm

Snob talk - someone has some "pro" equipment, and only that can reliable do it. Because overclock of home computers is unreliable :mrgreen: Then using word "precision" - like some hifi idiot. The whole MFM writing on floppy is not about precision. Digital concept is made just to avoid need for high precision - if signal is in range between allowed max and min - considering amplitude and timing it is perfect.
Unreliable over years ? It has not much with sector/track count - if gaps are enough big and overall signal level is good, and of course floppy self is good quality it will be well readable even after 20 years. My 1.6 MB floppies, done with my 520 ST and HD mod are still well readable - after 24 years. But not all - some brands are crap, some are very good. So, how should 12 s/tr be unreliable, while 20 s/tr is very reliable ? Because I did not spend lot of money on some duplicator it most be bad :mrgreen: No thanx. this was worst kind of bragging, on wrong place. Try to dig out some French diskmags instead.
Negative feedback has usually positive effect.

User avatar
dlfrsilver
Atari God
Atari God
Posts: 1419
Joined: Mon Jan 31, 2005 1:41 am
Contact:

Re: Help wanted: Imaging a protected disk

Postby dlfrsilver » Thu Jan 28, 2016 11:33 pm

AtariZoll wrote:Snob talk - someone has some "pro" equipment, and only that can reliable do it. Because overclock of home computers is unreliable :mrgreen: Then using word "precision" - like some hifi idiot. The whole MFM writing on floppy is not about precision. Digital concept is made just to avoid need for high precision - if signal is in range between allowed max and min - considering amplitude and timing it is perfect.


Not snob talk. I paid the one i had a few years ago 99 euros (it was sold 25000 pounds back in the day).

You can overclock any standard computer, you will never achieve a result as good as the one with an industrial machine. Why do you really think those machines had a cost of an engineer's year salary in end 80's - early 90's ? The reason is that it traces a very clean and precise signal that FDC in PC, ST, Amiga, C64, CPC, Spectrum can achieve.

You're not the only who tried to copy floppies with clock speed change and variable motor speed. We don't all live in Poland :mrgreen: !

There is no digital involved with disk written on standard equipment (understand computers). The copies are analogic, that's why the signal is unreliable when done on a personal computer.

What you're actually saying if we transpose the case in the Audio/musical department, "my music tracks are written as good on CD with a CD writer as the ones an industrial grade equipment costing thousands or even millions of euros can trace".

Do you realize how incorrect and inaccurate it is ? Any engineer would laugh at you ! :coffe:

Unreliable over years ? It has not much with sector/track count - if gaps are enough big and overall signal level is good, and of course floppy self is good quality it will be well readable even after 20 years.


The more you fork on a disk with a standard drive, with faster clock or not, and the more unreliable it's going to be.

This is no magic, there's no sorcery, it's just related to electronics and magnetic properties.

My 1.6 MB floppies, done with my 520 ST and HD mod are still well readable - after 24 years. But not all - some brands are crap, some are very good. So, how should 12 s/tr be unreliable, while 20 s/tr is very reliable ?


Ok, let me explain then : On prophecy viking child, each 12 sector track is 6280 bytes long, with almost no GAP, and each tracks are shifted + data over index. The 12th sector roll up above the index. I checked the density, it's normal density (2us) and not higher density at all.

Just do a test, trace the IPF on fresh disks, and then speedlock the clock of your 520 ST. You will never be able to copy the format, even with the faster clock.

You're a great coder, i admire you for that (thanks for the prophecy install), but please stop the "funny" facts about the hardware :)

Because I did not spend lot of money on some duplicator it most be bad :mrgreen: No thanx. this was worst kind of bragging, on wrong place. Try to dig out some French diskmags instead.


It's not a story of money. The purpose of those machines was to make their users able to make or create impossible to write disk formats on regualr and standard machines.

Which was in fact the goal of a copy protection :) You can read the format but not replicate it.
Now SPS France representative since the 19th of June 2014. Proud to be an SPS member !

AtariZoll
Fuji Shaped Bastard
Fuji Shaped Bastard
Posts: 2904
Joined: Mon Feb 20, 2012 4:42 pm
Contact:

Re: Help wanted: Imaging a protected disk

Postby AtariZoll » Fri Jan 29, 2016 8:55 am

The show must go on :D
Just about Prophecy and it's 12 sector/track - only first 4 tracks only on first floppy are 12 s/tr. Others are 10 s/tr - pretty much standard by ST SW. And that's just one of popular copy protection systems. Yes, no higher density, but no 12 real and full sectors too. There is sector overlap and fuzzyness. Nothing from 12x512 bytes data - and we here talked about such case, so please leave out copy protections from this thread. Btw. instead 12x 512 byte sectors is much better to use 6x 1K sectors (less gap) - and what a miracle - that IS used in most of Atari cases :P
Silver, I will call you DrGold if you try to change your attitude and realize that your technical knowledge is just not on level. I'm not some big floppy expert, but as may see easily see your mistakes.
Considering duplicators and data reliability: of course, they can write more quality as usual home floppy equipment. But that difference is really small, and much more important is quality of media. Duplicators are made for fast duplication in first place. Copy protections are additional feature - they invented data patterns not writable with regular computers. That is when we can say that you can not do it with your Atari or PC. But that has nothing with reliability. Btw. there are cases when you can copy original on other platform - with Amiga can copy some Atari protected ones, and even with PC copy of original Virus for instance is possible. But reliability depends mostly from floppy drive, and not FDC chip, because it sets proper level of signal on write head. FDC can not do it - it can just give some instructions about correcting level in higher tracks.
Back to original - 12 sector/track is just good idea to use capabilities of duplicators, which were in copy protection purpose - variable density. Better would be 6x 1K sectors, but that would be then not readable via TOS. Atari's floppy driver in TOS is flexible, and can handle well any s/tr, unlike DOS/Windows.
And please, please do not reply on this unless you have something really reliable to say - run it through your duplicator first :mrgreen:
Negative feedback has usually positive effect.

JimDrew
Atari Super Hero
Atari Super Hero
Posts: 638
Joined: Mon Nov 04, 2013 5:23 pm

Re: Help wanted: Imaging a protected disk

Postby JimDrew » Fri Jan 29, 2016 3:48 pm

cb wrote:Bottom line: don't image your disks on PC, do it on a real ST using Pasti instead. Much more reliable.


I prefer to use something more exact - like SuperCard Pro. No such thing as sectors at that point. :)
I am the flux ninja

User avatar
dlfrsilver
Atari God
Atari God
Posts: 1419
Joined: Mon Jan 31, 2005 1:41 am
Contact:

Re: Help wanted: Imaging a protected disk

Postby dlfrsilver » Fri Jan 29, 2016 4:06 pm

AtariZoll wrote:The show must go on :D


Yay !!! :lol:

Just about Prophecy and it's 12 sector/track - only first 4 tracks only on first floppy are 12 s/tr. Others are 10 s/tr - pretty much standard by ST SW. And that's just one of popular copy protection systems. Yes, no higher density, but no 12 real and full sectors too. There is sector overlap and fuzzyness.


I was only talking about the 12 sectors per track part of the disks, not the usual 10 sectors used for the remaining of the disks, that any drive can copy two hands tied in their back :)

Those are REAL sectors. there is no sector overlap, it's shifted tracks with Data over index. 11 sectors full, and the last one is rolling up on the top of the track.

there is no overlap. the KBI-19 is using overlapping sectors. Not the protection used by PVC.

Nothing from 12x512 bytes data - and we here talked about such case, so please leave out copy protections from this thread.


Some datas are stored inside those tracks. It's not just the copylock alone and the data over index used.

Btw. instead 12x 512 byte sectors is much better to use 6x 1K sectors (less gap) - and what a miracle - that IS used in most of Atari cases :P


This is a legend. The MFM short copylock tracks of PVC have almost no gap. Fire up Aufit, and check visually instead of saying things without checking.

what you must understand is that the disks format are platforms agnostic, this means that the only thing that count is to make a format that can be replicated correctly by the trace machine. Whatever that the tracks use no CRC or have a CRC.

After that, out of the format, it depends from the programmer. You have fast loaders on ST, as well as very slow ones, no matter the amount of sectors present on the disk.

Silver, I will call you DrGold if you try to change your attitude and realize that your technical knowledge is just not on level. I'm not some big floppy expert, but as may see easily see your mistakes.


Yours is not on level on the hardware side. Before going with SPS i had to learn and train about what i have under my very eyes.

I am not only competent on the ST side, but also Amiga, CPC, PC, Spectrum. I got more than a thousand different disk format (standard, weak sector, fuzzy sector, DOI sector, Copylocks, variable density sectors, longtracks, and so on).

Your knowledge only cover the Atari ST. Out of this, you're out :mrgreen: !

Considering duplicators and data reliability: of course, they can write more quality as usual home floppy equipment.


I'm so happy to read it from you ! :D ppfffuu... that was close :mrgreen:

But that difference is really small, and much more important is quality of media.


You're plain wrong here. Let me tell you why ;)

The difference is so important that the CTA analyser we use at SPS can easily distinguish a disk written by a trace machine, and a disk written by an atari ST (since it is the machine we talk about).

A Disk duplicated or made on an ST has 2 caracteristics, the first one is that the signal written on the disk looks "dirty" (not dirty like dirty clothes, but dirty like not clean). The second one is that an ST drive, like a CPC or a PC drive when writing on a disk have gap size irregular.`

A trace machine written disk has 2 caracteristics, the first one is that the signal written on the disk is very "clean" and "accurate". The 2nd caracteristic is that the gap space between every sector is always the same size, and it's also accurate.

That's how we know how a disk is modified, written on an ST or modified on an ST, or a genuine traced disk.

But in the end, i agree with you on the fact that yes, you need to have a good quality media :)

Duplicators are made for fast duplication in first place.


Ok you have a point here :) Indeed, it's making faster batches of disks for retailing them :)

Copy protections are additional feature - they invented data patterns not writable with regular computers. That is when we can say that you can not do it with your Atari or PC. But that has nothing with reliability.


You're right again when you say that it is indeed to make patterns impossible to write with regular computers.

But unfortunately, and we saw it until now, some of those patterns age very badly, causing issues in term of reliability.

Btw. there are cases when you can copy original on other platform - with Amiga can copy some Atari protected ones, and even with PC copy of original Virus for instance is possible.


Indeed, that's because the Amiga has in fact no real FDC. Enchanted Lands master has been made on Amiga for instance. I remember that back in the day, in ST computers clubs they had an Amiga with them in order to duplicate their softwares.

But reliability depends mostly from floppy drive, and not FDC chip, because it sets proper level of signal on write head. FDC can not do it - it can just give some instructions about correcting level in higher tracks.


You have a point here too. However, you can't compare a standard PC drive (even the sony ones), with a special or specific Sony drive used in duplicators (those were costing more than 2000 euros alone !).

Like i said, the drives and FDCs in computers are just 10 times less good than the ones in industrial machines.

The drive i had in my Trace machine got broken, and i was unable to replace it (the cost was just impossible for me to afford, and the drive could not be replaced by a standard PC drive.

Back to original - 12 sector/track is just good idea to use capabilities of duplicators, which were in copy protection purpose - variable density.


There is no variable density used in the 12 sectors track scheme. They used 2us per bitcell. If you want to see an ST game using variable density, go check P47 freedom fighter from Firebird. When variable density applies, the signal traced on the disk is like squeezed, instead of being like a long spaghetti.

Better would be 6x 1K sectors, but that would be then not readable via TOS. Atari's floppy driver in TOS is flexible, and can handle well any s/tr, unlike DOS/Windows.


Well any format suits, from the moment it's reliable to work with. Reliability is not related with the amount of sectors written, but is tied to the quality of the signal traced on the magnetic surface.
Now SPS France representative since the 19th of June 2014. Proud to be an SPS member !

User avatar
cb
Fuji Shaped Bastard
Fuji Shaped Bastard
Posts: 3039
Joined: Sat Apr 27, 2002 7:03 pm
Location: somewhere in time

Re: Help wanted: Imaging a protected disk

Postby cb » Fri Jan 29, 2016 4:19 pm

JimDrew wrote:
cb wrote:Bottom line: don't image your disks on PC, do it on a real ST using Pasti instead. Much more reliable.


I prefer to use something more exact - like SuperCard Pro. No such thing as sectors at that point. :)


Yes - but for people with just an ST and no extra hardware, Pasti is a brilliant piece of software. :)
Heghlu'meH QaQ jajvam!
Image

AtariZoll
Fuji Shaped Bastard
Fuji Shaped Bastard
Posts: 2904
Joined: Mon Feb 20, 2012 4:42 pm
Contact:

Re: Help wanted: Imaging a protected disk

Postby AtariZoll » Fri Jan 29, 2016 5:40 pm

I really don't see that it will ever end. So, to finish from my side: thread should be closed, case is solved. I cracked only one copyprotected disk.
All this duplicator blah is really off topic.
Before Atari I had Sinclair Spectrum - still have it. http://zx48.8bitchip.info/zx.php
There is floppy IF project for it, done with WDC1772 - because I was familiar with it. I wrote all SW, format , copy, conversion - and moved thousands of cassette programs to floppies.
I did not say that 12 sector/track is done with variable density, but with higher, constant density - as Jim Drew did too. You can not put 12 sectors - there is no so much space. Gaps are there from 2 reasons: writing can not start on 100% exact loc. so need some space around. Some time is needed for FDC chip to get ready for next ID, sector data read. There are cases with 6x 1K sectors, but last one is shorter, with 'custom' CRC - Space Ace, Wrath of the Demon - all it is written with duplicators, but they did not go on full 6KB per track - must be dumb 'only ST' floppy types :-)
Of course that it seems dirty when you write sectors separately, and not in formatting self. But that's how whole floppy handling is solved. What is relevant is that I still can read all that "crap" on quality floppies. While I have some originals with errors.

Moderators, please close this - really no need for more talk about who what duplicators have, and some tidy talk. FDC chips do very accurate timings - quartz clocked, and data line is pure digital - so all is in timing and nothing in some cleanness.
Negative feedback has usually positive effect.

User avatar
troed
Atari God
Atari God
Posts: 1212
Joined: Mon Apr 30, 2012 6:20 pm
Location: Sweden

Re: Help wanted: Imaging a protected disk

Postby troed » Fri Jan 29, 2016 5:58 pm

AtariZoll wrote:I'm done with this thread and *silver . Someone should just delete all his posts here, because they are completely unnecessary, not help anything - he just wants to show how he smart and experienced is, while writes huge stupidities and nonsenses - over and over again. No respect for such people. I respect facts and constructive posts.


AtariZoll wrote:So, to finish from my side: thread should be closed


AtariZoll wrote:Moderators, please close this


IMHO the only person who can request the closing of a thread is the thread starter. Only Robson can decide whether the discussion is still of interest to the original topic.

I've enjoyed both your posts and the posts by dlfrsilver. I do believe we're all adults nowadays and can appreciate two sides to an argument.

/Troed of I.C.S - who was lucky enough to never have had to care about strange disk formats when cracking

User avatar
dlfrsilver
Atari God
Atari God
Posts: 1419
Joined: Mon Jan 31, 2005 1:41 am
Contact:

Re: Help wanted: Imaging a protected disk

Postby dlfrsilver » Fri Jan 29, 2016 6:05 pm

Thanks Troed :)
Now SPS France representative since the 19th of June 2014. Proud to be an SPS member !

User avatar
Robson
Atari Super Hero
Atari Super Hero
Posts: 631
Joined: Sun Feb 19, 2006 7:03 am
Location: London

Re: Help wanted: Imaging a protected disk

Postby Robson » Fri Jan 29, 2016 6:22 pm

I walked away from this keyboard-karate when said the things quoted.

I'm glad that the initial issue has been resolved and there is a complete list of a short-life Atari diskmag preserved. Also triggered the appearance of the 2 games on Atarimania.

It's Friday anyway, beer o'clock.

:cheers:


Robson wrote:It's interesting to read even if it's a bit off topic now

Thank for your help. All of you.

Please respect each other.
------------------------------------------------
http://www.tercsirobi.byethost14.com
------------------------------------------------

User avatar
dlfrsilver
Atari God
Atari God
Posts: 1419
Joined: Mon Jan 31, 2005 1:41 am
Contact:

Re: Help wanted: Imaging a protected disk

Postby dlfrsilver » Fri Jan 29, 2016 6:52 pm

Yes, Beer o'clock (i'm sipping one in front of my keyboard :P!)
Now SPS France representative since the 19th of June 2014. Proud to be an SPS member !

AtariZoll
Fuji Shaped Bastard
Fuji Shaped Bastard
Posts: 2904
Joined: Mon Feb 20, 2012 4:42 pm
Contact:

Re: Help wanted: Imaging a protected disk

Postby AtariZoll » Fri Jan 29, 2016 7:31 pm

Yes, I could do same and drink beer, but will wait with that until May. The problem here, and in some other threads is that some people jumps in, not giving any useful advice, but to teach others and brag with his equipment and like. Just look posts carefully, and will see what I talk about. Easiest is to ignore whole thing, and turn head aside. What I do usually in similar cases. Going in discussion however gave me some clues about current forum moderating - it seems that Dal got tired from it, and let to someone other to deal with :-)
In any case, it was not only silver who brought here unnecessary duplication talk - thread was about imaging those disks, not writing. Of course that it can be done with SPC or Kryo, or whatever - but who will buy it for 4-5 floppies and little protection. Long live Pasti .
Negative feedback has usually positive effect.

AtariZoll
Fuji Shaped Bastard
Fuji Shaped Bastard
Posts: 2904
Joined: Mon Feb 20, 2012 4:42 pm
Contact:

Re: Help wanted: Imaging a protected disk

Postby AtariZoll » Fri Jan 29, 2016 7:43 pm

troed wrote:I've enjoyed both your posts and the posts by dlfrsilver. I do believe we're all adults nowadays and can appreciate two sides to an argument.


I proposed to close thread - and we know where things gone in some others with silver. His arguments are just not good in most cases. It's all about what is your priority - to be "nice", "friendly" and let things what you not approve unanswered, or arguing in purpose that people can read proven facts - discovered by few ones who dealt with it. Here I count of course not only myself - I read lot of literature about floppy controllers in last 28 years.
What makes me sad, and writing this post is that all this was in fact waste of time, because almost nobody cares for things I care. But trust me, all what I achieved was because being very nitpicking for details and going in core of problem.
Negative feedback has usually positive effect.

ijor
Hardware Guru
Hardware Guru
Posts: 3138
Joined: Sat May 29, 2004 7:52 pm
Contact:

Re: Help wanted: Imaging a protected disk

Postby ijor » Wed Feb 03, 2016 12:32 pm

I don’t think you can put 12 full 512 bytes sectors on a double density track, not to be able to read them back reliably.

You can put many short, partial, overlapped sectors if you want. Some protections put more than 100 sectors in a single track. With some limitations such a track can be created even with standard ST hardware. But this is of course useless for the purpose of packing more data.

11 sectors is possible, and as a matter of fact it was quite popular, although it is already not very reliable. There is a reliable way to put the same amount of data as 11 sectors. Use a custom format with 5 big (1024 bytes) sectors and a normal (512 bytes) one. You get the same number of data bytes but with less overhead (headers and gaps). This was used by some commercial disks. But it requires a custom file system. GEMDOS can’t read such tracks.

Disks created with special hardware can put more data. A custom controller can use smaller gaps, and write at a faster frequency (equivalent to the disk rotating slower). But 12 sectors would require a frequency too high, possible but not reliable. I don’t recall any commercial disk like this. Yes, there are protections with very long tracks. But the data on those tracks wasn’t important.

Lastly, an ST can create tracks with one extra sector header at the beginning of the track. This was an option on some custom formatters. Not for more data, but for speed. TOS read such a track a little bit faster. So you may see tracks with 12 headers, but only 11 ones have data.

AtariZoll
Fuji Shaped Bastard
Fuji Shaped Bastard
Posts: 2904
Joined: Mon Feb 20, 2012 4:42 pm
Contact:

Re: Help wanted: Imaging a protected disk

Postby AtariZoll » Wed Feb 03, 2016 12:52 pm

Thanx Ijor - I hope now *silver will go in discussion with you :mrgreen:

As said. there are games with 6x 1K sectors, but lust one is shorter - Wrath of the Demon for instance - that's reason why cracks are on more floppies than original.
And yes, there are disks with extra header - I seen lot. The reason is that TOS has verify flag on, so first test on correct track. I think that skew is much better than it - and it is used at TOS 2.06 formatter.
Negative feedback has usually positive effect.

JimDrew
Atari Super Hero
Atari Super Hero
Posts: 638
Joined: Mon Nov 04, 2013 5:23 pm

Re: Help wanted: Imaging a protected disk

Postby JimDrew » Thu Feb 04, 2016 2:45 pm

ijor wrote:I don’t think you can put 12 full 512 bytes sectors on a double density track, not to be able to read them back reliably.


You can get 12 to fit at a higher data rate and basically no track gap, but that is the max with a 1772 (it won't read 13 sectors at a data rate high enough to fit).
I am the flux ninja

User avatar
dlfrsilver
Atari God
Atari God
Posts: 1419
Joined: Mon Jan 31, 2005 1:41 am
Contact:

Re: Help wanted: Imaging a protected disk

Postby dlfrsilver » Thu Feb 04, 2016 7:06 pm

ijor wrote:I don’t think you can put 12 full 512 bytes sectors on a double density track, not to be able to read them back reliably.


Hello Ijor :) Of course, in the case i was talkin' about, it's a custom track written by a trace machine, so there's no reliability problem (it's the pre-copylock ST disk protection, called Copylock MFM short, it exists only on ST and PC machines, i found it on some titles like Dr Doom's Revenge, Prophecy The Viking Child, Ivanhoe to give out some names (there are many more !). The protection is spanned over 4 double sided tracks, with 12 sectors.

11 sectors are used for data, the 12th is the protection sector (basically the whole track is shifted, and it has Data over index, because the 12th sector roll up over the index).

My point was that a trace machine can reliably write such a track with no problem (Rob Northern used it on many games), but not reliably with a standard Atari ST.

I was so stating that people saying it's not reliable are wrong. It's simply depends on the hardware used to write such a track.

You can put many short, partial, overlapped sectors if you want. Some protections put more than 100 sectors in a single track. With some limitations such a track can be created even with standard ST hardware. But this is of course useless for the purpose of packing more data.


Indeed :)

11 sectors is possible, and as a matter of fact it was quite popular, although it is already not very reliable. There is a reliable way to put the same amount of data as 11 sectors. Use a custom format with 5 big (1024 bytes) sectors and a normal (512 bytes) one. You get the same number of data bytes but with less overhead (headers and gaps). This was used by some commercial disks. But it requires a custom file system. GEMDOS can’t read such tracks.


Once again, the real question is : "do we talk about a trace machine writing it, or a standard ST. Writing 11 sectors per track is not reliable on an ST.
On my 1040 STF, it never was, whatever the tool used.

However, with a trace machine, you write such a track easily, with gaps a bit longer than what you would get with an ST.

Disks created with special hardware can put more data.


Indeed :) And the signal written quality is higher on those disks :)

A custom controller can use smaller gaps, and write at a faster frequency (equivalent to the disk rotating slower).


Faster, and slower, in order to make short or long tracks, both being impossible to write back :)

But 12 sectors would require a frequency too high, possible but not reliable. I don’t recall any commercial disk like this. Yes, there are protections with very long tracks. But the data on those tracks wasn’t important.


the protection i talked about, as said, use 11 sectors for data, and a 12th one for protection. The very nature of this track makes it impossible to write on a standard ST or any other computer (even the amiga).

Lastly, an ST can create tracks with one extra sector header at the beginning of the track. This was an option on some custom formatters. Not for more data, but for speed. TOS read such a track a little bit faster. So you may see tracks with 12 headers, but only 11 ones have data.


it's not the case for PVC or Dr Doom ; the 12th sector is "cut" and its last part is written over the index. Such a protection, being made by rob northern was mastered on a trace machine.

But you're right about the content, only the 11 first sectors are used :)
Now SPS France representative since the 19th of June 2014. Proud to be an SPS member !

ijor
Hardware Guru
Hardware Guru
Posts: 3138
Joined: Sat May 29, 2004 7:52 pm
Contact:

Re: Help wanted: Imaging a protected disk

Postby ijor » Sun Feb 07, 2016 3:06 pm

dlfrsilver wrote:
ijor wrote:I don’t think you can put 12 full 512 bytes sectors on a double density track, not to be able to read them back reliably.


Hello Ijor :) Of course, in the case i was talkin' about, it's a custom track written by a trace machine, so there's no reliability problem (it's the pre-copylock ST disk protection, called Copylock MFM short, it exists only on ST and PC machines, i found it on some titles like Dr Doom's Revenge, Prophecy The Viking Child, Ivanhoe to give out some names (there are many more !). The protection is spanned over 4 double sided tracks, with 12 sectors.


Hi drfsilver,

Yes, I know that protection. But those tracks do not have 12 full 512 byte sectors. Sectors eleven and twelve are overlapped. The header for sector number 12 starts just after sector number 11 data block.

Once again, the real question is : "do we talk about a trace machine writing it, or a standard ST.


The point is that we are talking about 12 full 512 bytes sectors, each one with arbitrary data independent from the others. For the purpose of packing as much data as possible.

ijor
Hardware Guru
Hardware Guru
Posts: 3138
Joined: Sat May 29, 2004 7:52 pm
Contact:

Re: Help wanted: Imaging a protected disk

Postby ijor » Sun Feb 07, 2016 3:08 pm

JimDrew wrote:You can get 12 to fit at a higher data rate and basically no track gap, but that is the max with a 1772 (it won't read 13 sectors at a data rate high enough to fit).


Yes, it is possible, I said so in my post already. The question is how reliable this is. Especially when you read the disk in a different drive than the one you recorded it.

AtariZoll
Fuji Shaped Bastard
Fuji Shaped Bastard
Posts: 2904
Joined: Mon Feb 20, 2012 4:42 pm
Contact:

Re: Help wanted: Imaging a protected disk

Postby AtariZoll » Sun Feb 07, 2016 3:31 pm

I must comment all this - so much talk about very simple issue - putting 12 full sectors on DD floppy track. If they released Atari ST DiskMag Bomba on such, it should be enough reliable - I guess that they tested it little more than Tetra Quest US edition was tested :D Someone should really apologize for all unnecessary SQL space waste (for the XX-th time).
Negative feedback has usually positive effect.

User avatar
dlfrsilver
Atari God
Atari God
Posts: 1419
Joined: Mon Jan 31, 2005 1:41 am
Contact:

Re: Help wanted: Imaging a protected disk

Postby dlfrsilver » Mon Feb 08, 2016 7:15 pm

this Atari ST disk mag must have been written by a trace machine, industrially duplicated, hence the reliability :)
Now SPS France representative since the 19th of June 2014. Proud to be an SPS member !


Social Media

     

Return to “Floppy Disk Preservation”

Who is online

Users browsing this forum: No registered users and 2 guests