Cracked my first game: Gemini Wing - Page 2

dlfrsilver · 14 February 2007, 22:46

it's logical not physical ! a long track once ripped is around 10-15kb when a
standard one is 6kb~

maybe we could ask IFW for longtrack size and number of sector, hmm ?

Toni Wilen · 14 February 2007, 23:39

Number of sectors is irrelevant. Amiga hardware does not need or use "physical" sectors.

You can have single sector (sector equals single track) or you can create your own disk format with 100 sectors if you want

AmigaDOS format uses 11 "logical" sectors.

Quote:

a long track once ripped is around 10-15kb when a standard one is 6kb~

You are mixing MFM encoded and decoded tracks. Standard length of track is easy to calculate.

300RPM = 300/60 = 5 revolutions/sec. 2us bit rate = 500 000 bits/sec. 500 000 / 5 = 100 000 bits per track = 12500 bytes per track = 6250 MFM encoded bytes. (it isn't exactly 100000 because exact bit rate is slightly less than 2us)

Long tracks have ~10% more data per track. More than that and Paula will have problems reading it.

dlfrsilver · 14 February 2007, 23:53

ok thanks for the explanation, but what happens when you lower the RPM ?
you write more data on the track right ? i have read in a french site from
a guy who was mastering disks for silmarils as ex, they lower the drive when
writing on a track to write more on it and then create a long track.

i'll find back and translate here this guy infos.

musashi5150 · 15 February 2007, 09:11

Quote:

Originally Posted by dlfrsilver

ok thanks for the explanation, but what happens when you lower the RPM ?

Yes, they lower the drive speed by up to ~10% to get more data onto it (longtrack), but any more than that and the Amiga can't read it...

Toni Wilen · 15 February 2007, 09:12

Quote:

Originally Posted by dlfrsilver

ok thanks for the explanation, but what happens when you lower the RPM ?
you write more data on the track right ? i have read in a french site from
a guy who was mastering disks for silmarils as ex, they lower the drive when
writing on a track to write more on it and then create a long track.

i'll find back and translate here this guy infos.

Yes, it is possible to write long tracks by lowering RPM of floppy drive. (or perhaps by increasing the speed of Amiga's clock crystal but I am not sure if it can work in practise..)

musashi5150 · 15 February 2007, 09:16

Quote:

Originally Posted by Toni Wilen

(or perhaps by increasing the speed of Amiga's clock crystal but I am not sure if it can work in practise..)

These guys say that's exactly what they did with their game...

http://www.lightstorm3d.com/portfoli...protection.htm

The picture used to work when I last visited the site, but is missing for me this morning...

Joe Maroni · 15 February 2007, 11:18

i´ve talked to Jens Schoenfeld last week about longtracks and how to remaster them...

well...it is possible with the Catweazle MK4 he gave me some docs about how the catweazle works, but sadly i have never developed a driver for Windows.

and as i remember he is one (or the only one) of the "inventors" of longtracks and provided them for Turrican 2.
he told me that the longtracks (i suppose he means T2) consists of 5,7% more data than a "normal" track.
he even like to develop a tool to remaster the ipfs but the SPS team don´t like to offer more details about the format...

Toni Wilen · 15 February 2007, 11:46

Every Catweasel version has been able to write long tracks. CW's problem has always been software support.

Joe Maroni · 15 February 2007, 13:37

why the hell don´t anyone like to write those drivers...

Toni Wilen · 15 February 2007, 14:11

No need for new driver features, writing standard track or long track are done identically, only the length of pulses in data stream are shortened if writing long tracks.

CW does not accept "normal" bit stream but length of pulses. Basically one byte = length of single pulse, in units of selected clock rate, MK3+ have different base clocks to max 56MHz if I remember correctly.

In theory writing SPS images should be possible with CW (at least simple long tracks and tracks with variable bit rates, not sure about positioning relative to index)

Biggest "problem" appears to be limited data available from SPS library, you only get data that you would get from real floppy drive (instead of "low level" data before weak bit processing etc..)

dlfrsilver · 15 February 2007, 14:11

yep it would be great !

redblade · 14 May 2008, 07:36

Was this a dual format disk i.e Atari/Amiga. if so the crack would work 100% okay on both machines?

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14 February 2007, 22:46	#21
dlfrsilver CaptainM68K-SPS France Join Date: Dec 2004 Location: Melun nearby Paris/France Age: 46 Posts: 10,412	it's logical not physical ! a long track once ripped is around 10-15kb when a standard one is 6kb~ maybe we could ask IFW for longtrack size and number of sector, hmm ?

14 February 2007, 23:53	#23
dlfrsilver CaptainM68K-SPS France Join Date: Dec 2004 Location: Melun nearby Paris/France Age: 46 Posts: 10,412	ok thanks for the explanation, but what happens when you lower the RPM ? you write more data on the track right ? i have read in a french site from a guy who was mastering disks for silmarils as ex, they lower the drive when writing on a track to write more on it and then create a long track. i'll find back and translate here this guy infos.

15 February 2007, 11:18	#27
Joe Maroni Moderator Join Date: Feb 2003 Location: Germany Age: 44 Posts: 1,303	i´ve talked to Jens Schoenfeld last week about longtracks and how to remaster them... well...it is possible with the Catweazle MK4 he gave me some docs about how the catweazle works, but sadly i have never developed a driver for Windows. and as i remember he is one (or the only one) of the "inventors" of longtracks and provided them for Turrican 2. he told me that the longtracks (i suppose he means T2) consists of 5,7% more data than a "normal" track. he even like to develop a tool to remaster the ipfs but the SPS team don´t like to offer more details about the format...

15 February 2007, 11:46	#28
Toni Wilen WinUAE developer Join Date: Aug 2001 Location: Hämeenlinna/Finland Age: 49 Posts: 26,505	Every Catweasel version has been able to write long tracks. CW's problem has always been software support.

15 February 2007, 13:37	#29
Joe Maroni Moderator Join Date: Feb 2003 Location: Germany Age: 44 Posts: 1,303	why the hell don´t anyone like to write those drivers...

15 February 2007, 14:11	#30
Toni Wilen WinUAE developer Join Date: Aug 2001 Location: Hämeenlinna/Finland Age: 49 Posts: 26,505	No need for new driver features, writing standard track or long track are done identically, only the length of pulses in data stream are shortened if writing long tracks. CW does not accept "normal" bit stream but length of pulses. Basically one byte = length of single pulse, in units of selected clock rate, MK3+ have different base clocks to max 56MHz if I remember correctly. In theory writing SPS images should be possible with CW (at least simple long tracks and tracks with variable bit rates, not sure about positioning relative to index) Biggest "problem" appears to be limited data available from SPS library, you only get data that you would get from real floppy drive (instead of "low level" data before weak bit processing etc..)

14 May 2008, 07:36	#32
redblade Zone Friend Join Date: Mar 2004 Location: Middle Earth Age: 40 Posts: 2,127	Was this a dual format disk i.e Atari/Amiga. if so the crack would work 100% okay on both machines?

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