Work-In-Progress Reports for March 2002

27 March 2002

Dumping Disk Updated: Various bug fixes to the last enhancement of the Amiga dumping disk user interface. * Completed Workbench 2 support. * Various fixes for this to work, now uses the Workbench 2 asl.library and a replacement "RequestFile" command if this version of Workbench is detected. * Only ask for which drive to dump if there is more than one drive detected. * Menu system a touch faster. * Now uses standard copy command. (more)

24 March 2002

Checksums & Descriptors 2: Analyser Enhancements Support for additive checksums with fixed or stored value. New Descriptor ReadySoft (new version - the first Dragon's Lair uses a different format) which is known to support games: * Space Ace * Space Ace 2 * Dragon's Lair: Time Warp * Guy Spy Plus any un-dumped ReadySoft games.

23 March 2002

Checksums & Descriptors: CCITT CRC16 CCITT is a standards body that produced what used to be the "de-facto" CRC (Cyclic Redundancy Check) that is used to verify there were no errors in a given piece of data (and still is for certain environments). You can find CRCs pretty much anywhere you can find data, especially nowadays - ironically media storage is more reliable now. (more)

21 March 2002

A Bit of Fun: How to damage a disk drive through seeking: * Seeking faster than specified. While some drive motors simply "ignore" fast seeking - the motor only steps if the signal is held long enough. Others can be damaged. Some C64/Amiga programs actually do this! * Seeking towards higher tracks, over specified limits. Some drives implement mechanics that "hard stops" the head, just like track 0 (track 0 is always hard stopped). (more)

18 March 2002

Disk Imaging Made Easier: The (now old) way of dumping your games for us was rather tedious. It required lengthy setup and command line usage. Instructions were provided, but it was still quite a unfriendly way to do things. (more)

17 March 2002

UAE Support & Analyser Data View: CAPS Support in UAE More talks with Toni about getting UAE to support CAPS images. Toni is thinking along the lines of making UAE support only one simple internal format that supports bit cell timing (and might be similar to the CAPS release format). Any type of floppy image format (CAPS, the various ADF formats, FDI, etc. (more)

12 March 2002

Multi Stage Decoder Nearly Complete: The new multi-stage decoder works excellently with disk formats such as the one used by Bobo where the protection consists of missing data blocks. It also works very well with some really broken disks that we have come across. For Bobo, the previous decoder tried it's best to assign the missing blocks - and it actually succeeded. (more)

9 March 2002

Analyser: New and Modified: New An MFM bit stream data type, with automatic MFM recording (not encoding!) detection and adjustable threshold descriptor using the MFM bit stream type. This can detect noise (unformatted) tracks. The scoring for the track reflects if any MFM encoded data is recorded on the track, so a 100% score means no recording - the noise track is completely random. (more)

7 March 2002

Some Information: Raw Data If some part of the disk is not MFM encoded, what is it? Well, there are a few things that can be on the disk: Raw * Sync values (not really MFM, just almost) * Some sorts of protection Data * Anything that is not decoded by the disk format MFM * Anything that (more)

5 March 2002

Analyser: New and Modified: New Automatic rescan of a track when the format is changed and a proper score value given to it. This is only a partial analysation and only the selected format is tested. New type added: "selected". This is applied to any format selected before a full analysation. After a full analysation sub-optimal formats are marked "changed". (more)

4 March 2002

Scan Range Counts Update + Release Format Notes: Scan Range Counts Update We did not think there was any point on improving on this anyway, but we also noticed that the long scanning time occurs only if the gap track does not start at the disk index position - much more rare than the previous estimation. Otherwise it is super fast to detect. If we did decide to improve on the time for processing this time, it would be a hack. (more)

3 March 2002

Scan Range Counts: Scan range counts are now fully implemented and support for undefined scan ranges for data and sync values. This allowed us to fully re-enable gap support. As previously stated, this was temporarily removed due to missing functions. Because of this, a gap track descriptor was added, and the block descriptors that implement gap scanning were modified. (more)

2 March 2002

Format Scoring + Descriptor Changes: New Weighted/Balanced Format Scoring System A weight value can now be defined for blocks and data links independently. A value of zero makes the associated item's sub-score irrelevant. Anything above '1' is a more and more "preferred" property. (more)

1 March 2002

Dungeon Master + Analyser Optimisation: Dungeon Master - An Integrity Example We have a damaged Amiga copy of this game. Since it has an AmigaDOS file system we thought we would try to copy all the files under workbench (see below for why), and they do indeed copy (we are not talking about the protection track here). (more)