Hi,
Can someone help me with the CD-ROM pathtable structure?
There must be some sort of structure in it!
I've included one example of a pathtable.
Hoping someone can help me.
Greetz,
Martijn Groen
You may read the pathtable from SAM Basic:
10 LET adr=81920
20 READ *0,0,16,0,adr (B-DOS command only!)
This will read the Primary Volume Descriptor sector from CD-ROM.
30 LET size=DPEEK (adr+132) (size of pathtable)
40 LET a=PEEK (adr+142), b=PEEK (adr+143)
50 LET c=PEEK (adr+140), d=PEEK (adr+141)
60 READ *a,b,c,d,adr
This will read the pathtable at adr.
Variable c will usually be 18,19 or 20
Variables a,b,c & d specify the 32-bit sector address
a = 32-bit high, LSB
b = 32-bit high, MSB
c = 32-bit low, LSB
d = 32-bit low, MSB
READ *a,b,c,d,adr,sectors may also be used.
This will read multiple sectors from CD-ROM.
Note that each CD-ROM sector will be 2048 bytes. That's four
times bigger than standard floppy & harddisk sectors.
CD-ROM's can have a maximum of 8 branches.
Pathtable example: Heretic II
Branch1 Branch2 Branch3 Branch4
ROOT BIN
(1)
HELP ---- IMAGES
(1) (3)
SETUP ---- BASE ---- VIDEO
(1) (4) (6)
---- DIRECTX ---- DRIVERS ---- ENG (11)
(4) (7) ---- FRN (11)
---- GER (11)
---- ITN (11)
---- SPA (11)
---- GAMESPY
(4)
---- TOOLKIT
(4)
Pathtable at adr:
Notice that I'v not included the 4-byte startsector in each entry.
1,0
1,0 - Root entry (not important)
0,0
3,0 - length of dir. name
1,0 - some sort of code
BIN - dir. name
0 - belongs to this or next entry?
4,0
1,0
HELP
5,0
1,0
SETUP
0
6,0
3,0
IMAGES
4,0
4,0
BASE
7,0
4,0
DIRECTX
0
7,0
4,0
GAMESPY
0
7,0
4,0
TOOLKIT
0
5,0
6,0
VIDEO
0
7,0
7,0
DRIVERS
0
3,0
11,0
ENG
0
3,0
11,0
FRN
0
3,0
11,0
GER
0
3,0
11,0
ITN
0
3,0
11,0
SPA
0
