cas2cas ; cas ; cover....

[St(r)yker]

Hello there !

 

You can download .cas files from this site. The archive will be updated

at a regular basis.

 

ftp://ftp.atari.art.pl/stuff/collections/stryker/cas/

 

-------------------------------------------------------------

 

If you have any interesting .cas files (fancy loaders are welcome) than

upload them here (only original .cas files made from cassetes, no .xex

or .com's adapted by the xex2cas program) :

 

ftp://ftp.atari.art.pl/upload/strykercas/cas

 

-------------------------------------------------------------

 

If you have original game covers, scan them (TIFF, 300 dpi) and upload

here:

 

ftp://ftp.atari.art.pl/upload/strykercas/covers

 

You can browse through the ones i already have here:

 

ftp://ftp.atari.art.pl/stuff/collections/...stryker/covers/

 

-------------------------------------------------------------

 

There is also a new program (beta) at

http://www.gdansk-orunia.eu.org/atari/cas2cas.zip made by Gienek by the

name of cas2cas. More info in the manual below :

 

-------------------------------------------------------------

Hello.

 

I've managed to write a new program designed for repairing .cas files.

It is a beta version so it can have its ups and downs.

 

 

 

It is a soft of supplement for the wav2cas program. Those who used

wav2cas know that the .wav to .cas conversion is subject to a lot of

possible errors. Most of these errors are smal flaws that make correct

readings impossible.The bigger the file, the more probable it is for an

error to occur in the file as a whole. Most of these errors are easy to

repair. It is quite obvious that if we make for example 3 .cas files out

of the same program, there is a large chance, that they can be merged

into one proper, error-free file. Manual repair is possible, but very

arduous. So why can't we order this task to be done automatically? And

that's exactly what i did...

 

 

 

The program is run by a script (maybe in the future I will write a GUI

for all programs from the "cas" family) :

 

cas2cas file1.cas file2.cas file3.cas file_good.cas

 

The program can also accept the hex format as input / output (the

default transmission speed is set to 600 bod's), for example :

 

 

 

cas2cas file1.hex file2.hex file3.hex file_good.hex

 

Of course we can mix "hex" and "cas". We can, for example, provide 2

.cas files and one slightly modificated .hex file.

 

The correct code (according to the algorithm) will be saved in

"file_good"

 

 

 

Tis program can also be used as a .hex to .cas and .cas to .hex

converter. All we need to do is type the same name of the input file 3

times in a row.

 

cas2cas file.hex file.hex file.hex file_good.hex

 

 

 

The output file is normalized (speed, inter record gaps), the checksum

gets corrected (for standard blocks) so we can explore and poke around a

little in the .cas file (file protection, invulnerability) and then

generate a file containing proper checksums.

 

 

 

Now i will present the way my program does the conversion, so you can

understand how to make the best use of it. If you have any interesting

ideas please share them with me. This is only a beta version so i

included the options which seemed the most usefull to me. The main idea

was to make the program as automatic as possible.

 

 

 

The program loads a .cas or .hex file to the memory in the form of

records. Analyzing starts from giving each record a status (a number) :

 

1 - if the record has a length of 132 and correct checksum

 

2 - if the record has a length of 132, but incorrect checksum

 

4 - if the record has different length, and correct checksum

 

5 - if the record has different length, and incorrect checksum

 

 

 

Then the program starts to scan all the records again, and if it finds a

record with the status "5" it can change the status to "3" (record which

should have had a 132 lenght) but only if at least one of the following

records has the lenght of 132. This way we can check which blocks are

incomplete.

 

 

 

Then we do the sorting. A block is chosen for the 3 available files

according to priority.

 

If at least one of the files is a "1" than it will be chosen. If all of

the files are "2" then all of them will be analyzed byte per byte and

the most probable version will be chosen. Then the checksum correction

is made. If a record with the status "3" is found (and no "1" records

are available), a search for the missing string is done. When a status

"4" record is found, it is left unchanged. If we get a status "5" record

- there is nothing we can do.

 

 

 

The program can crash if there are to many "3" errors, because it is

unable to find the begining of the next block. In some cases, manual

corrections done using only your intuition (or at random ;D ) can fix

the result - even one hex can count.

 

 

 

Next the inter record gaps are normalized, and the checksums are

corrected. In the end the file gets saved.

 

-------------------------------------------------------------

thx. Theo-Klex & Detox ;]

[St(r)yker]

Here you have a new version:

CAS2CAS v0.2

upgraded:

Cas2Cas with -orgsp option

so, he don`t change aborts