This repository is for tools aiding the reverse engineering of the Prodigy (Classic) Reception System.
Currently there are two Python 3 utilities, viewer and stageutl, that make use of a Python 3 library which provides some access to Prodigy's famous STAGE.DAT file.
Everything is in the middle of 2 rewrites. (The first rewrite was started a couple years ago and then I had to step away. In an attempt to get the code semi-decent enough to share, I've started a second re-write.) So the code could be better and the bugs are bountiful. Oh, and did I mention that I barely have any documentation regarding the insides of Prodigy? That doesn't help things either.
This is a sometimes fun utility for trying to get the Prodigy Reception System (RS.EXE, the Prodigy client) to execute program objects stored in a STAGE.DAT file and put some pretty NAPLPS text and graphics on the screen. This is what has been used to produce most of the Prodigy screen shots you may have seen.
This very simple utility works by getting a list of desired objects from STAGE.DAT and creates a MS-DOS batch file. You would then run this batch file under something like DOSBox and it will get the Reception System to load and execute each object in turn. Then, sometimes, something pretty will momentarily pop up on the screen.
A common invocation would be viewer --obj-type 4 --prompt STAGE.DAT.
This will create VIEW.BAT. You would then start DOSBox, go into the
Prodigy directory, and run VIEW. Hopefully, before too many objects,
you'll see something worth while. If it hangs you can check OBJECTS.LOG to
see the number of the problem object. Passing that number +1 to VIEW will
jump directly to that object, bypassing the hanging object.
This is a much more advanced utility. It can take a few different sub-commands, which I'll now very briefly cover.
STAGE.DAT is very close to a standard FAT file system. This will show how it's being used. (I got the idea from the TRSDOS "free" command.)
stageutl show-aum STAGE.DAT will produce something like:
0x0: X X - % - - - - - - - - - - - -
0x10: - - - - - - - - - % - - - - - -
0x20: - - - - - - - - - - - - - - - -
0x30: - - - - - - - - - - - - - - - -
0x40: - - - - - - - - - - - - - - - -
0x50: - - - - - - - - - - - - - - - -
0x60: - - - - - - - - - - - - - - - -
0x70: - - - - - - - - - - - - - - - -
0x80: - - - - - - - - - - - - - - - -
0x90: % - - - - - - - - - - - - - - -
0xa0: - - - - - - % - - - - - - - - -
0xb0: - - - - - - - - - - - - - - - -
0xc0: - - - - - - - 123 - - - - - - - -
...
0xdb0: U U U U U U U U U U U U U U U U
0xdc0: U U U U U U U U U U U U U U U U
0xdd0: U U U U U U U U U U U U U U U U
0xde0: U U U U U U U U U U U U U U U U
0xdf0: U U U U U U U U U U U U U U U U
0xe00: U U U U U U U U U U U U U U U U
0xe10: U U U U U U U U U U U U U U U U
0xe20: U U U U U U U U U U U U U U U U
0xe30: U U U U U U U U U U U U U U U U
0xe40: U U U U U U U U U U U U U U U U
0xe50: U U U U U U U U U U U U U U U U
0xe60: U U U U U U U U U U U U U U U U
0xe70: U U U U U U U U U U U U U U U U
The X's indicate non-existent “allocation units”. Hyphens (-) indicate the next AU in an object's chain is the one to the right. A percent sign (%) indicates the end of a chain. If it's a number then it indicates fragmentation and that number is the next AU in the chain. Finally, a U means it's not currently allocated.
And just like any file system, you need a way to see the objects contained within it.
stageutl dir STAGE.DAT gives a detailed directory listing:
line name loc type length stat auid ver stor check ssize
0001 2A00APPL.PG 1 4 49( 73) 1 70e 202 1f df1f 1
0005 2A00GATE.PGM 0 c 7b4( 1972) 1 70f 4c7 8 1e0f 0
0007 2A00LVER.BDY 0 8 515( 1301) 1 717 68f 7 cfd1 0
0016 2A00LVER.PGM 0 c 40( 64) 1 71d 447 5 0b3e 0
0018 4A001000.BDY 0 8 4b1( 1201) 1 755 432 0 453f 0
0092 4A001000.MEN 0 4 9f( 159) 1 754 417 0 c382 0
0097 4A00HSEL.PGM 0 c 3f( 63) 338 0 0
0101 4A00ADOM.WND 0 e 326( 806) 1 774 43a 0 b660 0
0136 4A00ADWI.PGM 0 c 316( 790) 1 779 432 0 99a5 1
0138 4A00ADWP.PGM 0 c 670( 1648) 1 77d 432 0 5220 1
0140 4A00AUTO.PGM 0 c b3( 179) 1 75c 417 0 0158 0
0142 4A00BIAD.PGM 0 c 315( 789) 1 7b2 432 0 b9d5 1
0144 4A00CKCM.PGM 0 c 613( 1555) 1 76d 432 0 5c86 1
0146 4A00CURS.PGM 0 c 1d( 29) 1 778 422 0 05a4 0
0148 4A00DREC.WND 0 e 122( 290) 1 795 422 0 4a54 0
0158 4A00ENTR.PGM 0 c 65e( 1630) 1 749 432 0 6a7c 1
...
The various columns are too technical to get into now. But I will tell you that when you see an object without an allocation unit ID (AUID), nothing is wrong. It simply means it's embedded in a prior object. So above, 4A00HSEL.PGM is inside of 4A001000.MEN.
This is a cool looking tool that will output data about objects in STAGE.DAT. Objects are made up of segments. When I know what a piece of data is, I try to parse it. Otherwise it is dumped raw. But hex dumps are sexy so there's nothing wrong with that.
stageutl view STAGE.DAT outputs something like:
0001 2A00APPL.PG 1 0x4 length=0x49(73) status=0x1 startid=0x70e(1806)
- version=0x202 store_candidacy=31 check=0xdf1f setsize=1
0002 | PageFormatCallSegment st=0x31 sl=0x11(17)
| | id : XXOF0010.FMT 0x0 0x0
| | parm : None
| | parm_length : None
| | prefix : 0xd (13)
0003 | ElementCallSegment st=0x21 sl=0x13(19)
| | id : 2A000251.HDR 0x0 0x8
| | parm : None
| | parm_length : None
| | part_id : 0x1 (1)
| | prefix : 0xd (13)
| | priority : 0x0 (0)
0004 | SelectorCallSegment st=0x20 sl=0x13(19)
| | id : 2A00GATE.PGM 0x0 0xc
| | parm : None
| | parm_length : None
| | part_id : 0x2 (2)
| | prefix : 0xd (13)
| | priority : 0x0 (0)
0005 2A00GATE.PGM 0 0xc length=0x7b4(1972) status=0x1 startid=0x70f(1807)
- version=0x4c7 store_candidacy=8 check=0x1e0f setsize=0
0006 | ProgramDataSegment st=0x61 sl=0x7a2(1954)
| | data : (1950 bytes)
0000 00 00 14 00 02 07 50 41 4c 43 48 41 54 33 0b 43 |......PALCHAT3.C|
0010 48 41 54 50 52 4f 46 49 4c 45 0e 7e 0f 26 0a 00 |HATPROFILE.~.&..|
0020 74 26 13 61 b6 07 00 05 1a 1e 6d bb 7f 04 00 13 |t&.a......m.....|
0030 8e 06 17 79 13 c3 01 20 00 5b 13 5e b5 0f 00 05 |...y... .[.^....|
0040 50 00 07 39 2e 31 37 2e 31 34 6f bb 7f 16 00 00 |P..9.17.14o.....|
0050 0d 32 41 30 30 49 4e 49 54 50 47 4d 00 0c de 00 |.2A00INITPGM....|
0060 7d 1b 00 26 01 85 03 00 0d 32 41 30 30 4c 56 45 |}..&.....2A00LVE|
0070 52 42 44 59 00 08 dd 03 c1 06 13 8e 28 00 0d 45 |RBDY........(..E|
0080 34 41 30 30 32 35 31 48 44 52 00 08 29 00 00 07 |4A00251HDR..)...|
...
This will allow the extraction of attributes from segments, segments from objects, and objects from the STAGE.DAT file. It is currently a victim of one of the rewrites I mentioned above. I'm not even sure it works. I'm not going to describe it now.