[OLD] FDD Index Impuls

Get Msg, Igor! 30 May 99 23:28, Igor Turashev reported to Vyacheslav Mednonogov about {copiers}: KF>>>> knew how to copy cross-sector garbage. And then there is the Amiga... FK>>> Amiga (1200) could not copy primitive protection for ZX_FORMAT#5. :) VM>> So, that defense was made by a specialist against the Amiga.. The fact was used VM>> that Amiga cannot copy a track longer than a certain length.. IT> What did they record it on then? And, IMHO, PC will also take little protection, IT> so that each protection is made for certain computers, and perverted and IT> you can always write off... In order not to chatter in vain, I present a couple of letters personally from Raks Mamanov: === Cut === ─ General Letters Archive (2:5030/675.30) ─────────── GENERAL.LETTERS.ARCHIVE ─ From : Max Romanoff 2:5030/221.16 26 Sep 97 16:46:32 To: Vyacheslav Mednonogov 29 Sep 97 00:22:10 Subj: FDD Index Impulses ─────────────────── ──────────────────── ──────────────────── ──────────────────── Vyacheslav is that you? ...why did you tell me about FDD Index Impuls? VM> Since you're done with Speck and Walker, share this secret of yours VM> - VM> everyone will be interested ;) There is no secret :)))) A track is written at a speed that differs from normal by +/-10 rpm... And that's it... Then, knowing the length of such specials. tracks - it's easy to understand what it is copy... The most important thing: tracks of different lengths can be made on one disc several, then pirates will not be able to simply copy (even on Amiga without a lotion), and you will have to break... This also applies to users, who do not have such knowledge and skills... You can check the length using the function: read track, having previously placed the data address at $0000... Thus, upon exiting TR-DOS, the required length will be in HL... Check it for error (+/- ~20 bytes)... and that’s all... Protection was successfully used in The Turn at one time... If anyone If you want to practice copying, I can give you the original :) Good Luck... -+- Mail Manager 1.22x/p #1501 + Origin: [censored] (2:5030/221.16@fidonet) ─ General Letters Archive (2:5030/675.30) ─────────── GENERAL.LETTERS.ARCHIVE ─ From : Max Romanoff 2:5030/221.16 28 Sep 97 17:50:04 To: Vyacheslav Mednonogov 30 Sep 97 01:19:42 Subj: FDD Index Impulses ─────────────────── ──────────────────── ──────────────────── ──────────────────── Vyacheslav is that you?...why did you tell me about FDD Index Impuls? VM> Regarding the Amiga: -10 rpm it will copy, but not +10 rpm? Or in VM> in both cases the length of the track will not be exactly repeated? In short, I’ll explain: Amiga can copy in 2 ways: 1. Read the entire track into memory, and then write. Because reading tracks are at the lowest level (MFM), it is possible to copy any protections based on left formats... This method is fast, but cannot copy tracks with a short long... No, he copies them, but the track becomes long standard for the speed at which the disk spins is written... why? Explanation: When reading a track, the hardware is synchronized via MFM, and reads the entire track. Because iron allows speed variations drive, THEN it basically reads in a wide range of bitrates. As a result, there is an image of the MFM track in memory, defined length (counted). A because MFM recording occurs with standard birtrate, then when writing, extra 'empty bits' will be written or even a sector is eaten (if the track was stretched)... As a result, we get an identical track, but its length changes in the usual direction. Which is controlled by the program. 2. Use a small external piece of hardware that allowscopy *DIRECTLY* from one drive to another (bypassing memory, a This means preserving *BCE* temporary characteristics of the recording)... The role of the computer in this case is to track indexes synchronization of both drives (the circuit confuses 3 signals with each other: RDDATA - WRDATA, SEL2 - WriteEnable, DiskChange - INDEX... Left - computer connector, on the right is the disk drive...), and when they match (plus, minus a few bytes) - writing to one is enabled, and reading to friend, and the track is recorded directly from one disc to another... The computer equalizes the speed of disk drives through short-term removals MOTOR signal... This copying method copies absolutely all protections (except scratched)... Including non-standard MFM + multi-speed record... The disadvantage of this method is its terrible slowness (after all Before copying a track (EACH), you need to combine the indices... and the greater the difference in speeds, the more time is needed)... This can be improved by synchronizing both drives from one quartz, but I haven't checked it... However, this method is still not suitable for replication disks... perhaps for one or two copies of some major, prone to self-destruction, or for oneself... It should be noted that theoretically, it is possible to docopies of tracks with different lengths (even make tracks with a length of 1 kb or something like that, which is impossible anywhere except Amiga)... The essence of the method is the basis of the work of disk hardware on the Amiga. For those who are not familiar, I will only say that the hardware writes to the disk prepared MFM data... And if among this data there is only a certain part is encoded using MFM (a pair of sectors with fields), and the rest will be 00, then VG93 will not be able to count such zero MFMs data, because they lack the synchronization required by VG93... As a consequence, we can assume that the length of the track will be equal to a lot of useful information... This theory has not been tested in practice, if anyone checks it, let me know I need to know about the results... p.s. turned it down, right? :) Good Luck... -+- Mail Manager 1.22x/p #1501 + Origin: Send 20$ to (2:5030/221.16@fidonet) === Cut === Warm greetings, Slava! [I.ZX] [Workers of all countries, unite!]