Changes

'''Speedlock''' is the name of a disc and cassette copy protection designed by Dave Looker ([[DJL]]) and Dave , David Aubrey-Jones. Earlier versions mentioned "DJL Software" later versions mentioned "Speedlock Associates"and Simon Berry.

It The Speedlock cassette loader was a modified version combination of the Spectrum's an encryption system and advanced cassette routines with protection added. It is often recognised for it's recognized by its blue/and black stripes in the border during loading. Later versions had multicoloured stripes for the leader/pilot tone, and then blue/black stripes for the data.

As the protection system continued to evolveCertain hacking software, programs such as [[Soft-Lok]] and the [[Bonzo Blitz]] were upgraded , attempted to break follow the protectiondevelopment to created unprotected versions of the protected software.

The speedlock Speedlock tape protections in their Amstrad CPC versions only use 4 3 different types of encoding :

Speedlock type 1 2 (1984-1986):

*Arkanoid Revenge A Speedlock-protected game with a baud rate of Doh,*Basket Master,*Crazy Cars,*Deliverance Stormlord II,*Gryzor,*Mercenary L'evasion de Targ,*Nigel Mansell GP,*Renegade (Hitsquad),*Road Runner,*Robocop,*Stallone Cobra,*Tank,*Target Renegade,*Tarzan,*The New Zealand Story,*World Games1900 is Speedlock v4. A Speedlock v6 will not exceed 1675 baud.

Speedlock type 3 4 (1900 baud) (1986-1988):  *Arkanoid Revenge of Doh*Basket Master*Crazy Cars*Deliverance Stormlord II*Gryzor*Mercenary: Escape From Targ*Renegade (Hitsquad)*Road Runner*Robocop*Stallone Cobra*Tank*Target Renegade*Tarzan (specific Speedlock)*The New Zealand Story*World Games

Special speedlock : *Altered Beast,Nigel Mansell GP => the main code is protected by Speedlock v4 while the level data uses Speedlock v2.*Back To the Future IIIdetermine whether a game uses Speedlock v4 or v6,*Bad Dudes vs Dragon Ninja,*Batman check the Movie,*Fighter Bomber,*Guerrilla War,*Hammerfist,*Monty Python Flying circus,*Mutants 64k,*Ocean Beach Volley,*Operation Wolf,*Operation Thunderbolt,*P47 Freedom Fighter,*Rainbow Islands,*SDI (activision)*Shinobi,*Star control,*Stormlord,*Super Wonderboy in monsterland,*The Addams Family 128k,*The Ninja Warriors,*The Untouchables,*Turrican II The Final Fight,*Typhoon,*Wizball,baud rate with CSW2CDT.

Speedlock type 4 6 (1675 baud) (1988-until the CPC death):Note that level data may use either the Spectrum variant 2 scheme, or the Sinclair Spectrum one.

One version called "[[8k Speedlock]]", relied on the fact that the CPC's hardware (specifically, the [[765 FDC|µPD765]] disk controller) could reliably read but not 8 Kbyte sectors even though it was typically only possible to store more than 6,250 bytes on 300 rpm double density diskettes. Attempting to write 8k an 8 Kbyte sector would cause the system to over-write its header block. It was written here that "the format was either devised or done on an Atari ST or an IBM PC compatible machine (since the CPC share with them the same FDC controler). The main difference being that an ST or PC can write more data per track than a CPC." This contains several inaccuracies. The Speedlock team in fact wrote the diskettes using diskette interfaces custom-modified for this purpose. Also, an Atari ST also has 6,250 bytes/track although used a WD1772 disk controller, while the PC has over time been based on a variety of formats (e.g. HD was 360 rpm 15 sectorsetc.) and controllers (e.g. NEC µPD765 or Intel 8272A or 82072A.

the format Another statement written here was either devised or done on an Atari ST or an IBM PC compatible machine (since : "In itself, a 'Speedlock track' exists in 2 versions, used at the CPC share with them discretion of the same FDC controler)duplicator, one use a CRC, and the other not. The main difference being " This is inaccurate, in the sense that an ST or PC can write more data per track than it was never at the discretion of the duplicator. There were at least two separate versions, one of which may have involved a CPCCRA issue.

In itself, a speedlock A 'Speedlock track exists ' consists of only 512 bytes declared for the sector while all the remaining data is spanned in 2 versionsa huge GAP section. When copied on a CPC, used at the discretion of FDC only stores the duplicator, one use a CRC512 first bytes as declared in the CHRN, and discards the remaining contained in the gap section. Those tracks have an EDC (Error Data Checksum) because only 512 bytes are used to calculate the data checksum as well as an illegal data field size. Several other protection mechanisms existed on such tracks, including special codes written by the Trace 1006 duplication equipment commonly in use at the time: these codes could notbe written by standard Amstrad disc drives.

A speedlock track consist of only 512 byte declared for the sector, and all the remaining data is spanned in a huge GAP section.When copied on a CPC, the FDC only store the 512 first bytes as declared in the CHRN, and discard the remaining contained in the gap section. Those tracks have an EDC (Error Data Checksum), because only 512 bytes are used Various methods were attempted to calculate the data checksumcircumvent this protection, as well as an illegal data field size.including:

There were two methods 1. A hardware modification to get around this: the Amstrad CPC and a special copy program .

12. A hardware modification to the Amstrad CPC and Executioner's utility Xexor included a special copy program 'brain file' solution to crack individual games before copying them.

23. ExecutionerThe Argonauts (Jason Brooks's utility Xexor included a 'brain file' solution ) 8K Disk Copier was sold both through Nemesis and Personally, it worked by approaching the issue the same as Tape to crack individual games before Disk copying themthe game code to standard sectors after the "Hack" and then copying protected sectors which contained level data at the end of the disk tracks. This can be found on the Git Repo: https://github. <br>com/muckypaws/AmstradCPC