The Tail of Beta Lyrae - Washouts

[+therealbountybob]

I'm glad to see after 7 years we are now taking this problem seriously!

Ok my original disk (with the washouts problem but was ok originally)

Sector 365: Byte 00=00 Byte 123=00 Byte 126=B1

Sector 369: Byte 00=00 Byte 123=00 Byte 126=B1

[+DjayBee]

We now have four different ATX-dumps (Farb, Atarimania and two from Zarxx).

They differ (only) in these aspects:

• The load-counter (1st byte of sector 365)
• The "serial number" (bytes $78-$7D of sector 365 - counting from $00)
• The format of the last track (duplicate / missing sectors) - This might be related to bad dumps.
• The bad-CRC sectors 9-15 (Single bytes with various values and ranges filled with either $00 or $FF)
• Various sectors are filled with either $00 or $FF

The game's code is identical between all of them.

 

If someone wants to go further in analyzing the game, I have attached everything I currently have.

 

The archives always contain a plain sector-copy of the ATX to work on.

The crack is based off Farb's dump and has the counter zeroed.

 

One weird fact I found is that the track alignment protection is deactivated. The timing results are always overwritten with $00:

4DB7: AD 14 D0          LDA PAL    ; seems to check for PAL
4DBA: 29 00             AND #$00   ; but ignores everything
4DBC: D0 06             BNE $4DC4  ; so will always be =$00
4DBE: 8D B5 2E          STA $2EB5  ; and overwrites the result-bytes
4DC1: 8D D9 2E          STA $2ED9  ; of the alignment check

Tail of Beta Lyrae - Atarimania.zip

Tail of Beta Lyrae - Farb.zip

Tail of Beta Lyrae - Zarxx-post77.zip

Tail of Beta Lyrae - Zarxx-post88.zip

Tail of Beta Lyrae - Crack.zip

Edited June 4, 2017 by DjayBee

[+DjayBee]

Sector 365: Byte 00=00 Byte 123=00 Byte 126=B1

 

I just noticed that I forgot to answer.

If byte 00=00 is then you probably have the disk write-protected and the game has not incremented the counter on the disk yet.

 

So either the washouts are random and not based on a certain value of the load-counter or it might be a result of failing copy protection.

Could your disk start failing?

[+therealbountybob]

 

I just noticed that I forgot to answer.

If byte 00=00 is then you probably have the disk write-protected and the game has not incremented the counter on the disk yet.

 

So either the washouts are random and not based on a certain value of the load-counter or it might be a result of failing copy protection.

Could your disk start failing?

The game seems to work otherwise so the disk itself doesn't have loading problems. It is not write protected, could be a fault or perhaps a fault at one time or another with a 1050 drive tripping the copy protection? But what about if the counter just wrapped round to 0

[+DjayBee]

But what about if the counter just wrapped round to 0

 

This is not possible because the game stops writing back the sector when the counter reaches $23 (35).

The whole code segment is contained in the documentation file inside the crack's archive.

4E34: AD 00 2D          LDA $2D00
4E37: C9 23             CMP #$23	# counter < $23 ?
4E39: B0 1B             BCS $4E56	# no => go ahead

4E3B: A2 05             LDX #$05	# yes => modify code ...
4E3D: A9 00             LDA #$00
4E3F: 9D 52 62          STA $6252,X
4E42: 9D F8 63          STA $63F8,X
4E45: 9D 71 64          STA $6471,X
4E48: CA                DEX
4E49: 10 F4             BPL $4E3F

4E4B: EE 00 2D          INC $2D00	# ... increment load counter (1st byte in sector) ...
4E4E: A9 57             LDA #$57
4E50: 8D 02 03          STA DCOMND
4E53: 20 53 E4          JSR DSKINV	# ... and write sector back

4E56: AD 5E E4          LDA SETVBV+2	# go ahead

Edited June 5, 2017 by DjayBee