Question about Prince Of Persia 2 1.1 demo

[DoutorHouse]

Quick question: what’s the origin of the Prince Of Persia 2 demo 1.1 floating around? Did it come from some PC Gamer cd or some Red Orb Entertainment game or some other source? I can’t find any information about it and it’s driving me mad... Thanks for any help!
Cheers!

[Norbert]

Quick question: what’s the origin of the Prince Of Persia 2 demo 1.1 floating around?

Possibly it was released as part of the Prince of Persia Collection Limited Edition.
Source: http://www.popot.org/popuw_forum_archive/2277a.html

[David]

According to http://www.popuw.com/download2.html:

Three demo versions for PoP2 are available.
First one is version 1.0 (1993 first official demo by Broderbund Software).
Second one is version 1.1 (1998 the one released within Prince of Persia Collection Limited Edition by Red Orb Entertainment - It has sound setup...).
Third one is the Macintosh version's demo.

The same page writes about Prince of Persia Collection: Limited Edition that it contains Prince of Persia 2: The Shadow and the Flame v1.1, but it doesn't say it's a demo. Strange...
I'm currently downloading the Prince of Persia Collection: Limited Edition to see what's in it.
(Norbert, you posted your post while I was writing mine! )

[DoutorHouse]

Thanks for your answers, guys! Unfortunately, i know for sure that the "Prince of Persia: Limited Edition" cd does not contain that demo, only the complete game. I own an original copy of that cd, published in 1999 by Softkey, and only the complete 1.1 version of POP2 is there. Same thing happens with the "Prince of Persia 2" cd from 1998... only the complete version is present, not the demo... So, my question remains... Any more ideas? Maybe the original US cd has it? Or maybe PC Gamer magazines or something like that? Thank a lot again!!!

PS: and does anybody want floppy disk images for versions 1.0, 1.1(!) and 1.3?

[Norbert]

PS: and does anybody want floppy disk images for versions 1.0, 1.1(!) and 1.3?

Yes, all three.
It may be interesting to compare your 1.1 with the Hit Squad disk image (attached, inside ZIP).

[DoutorHouse]

Well, my 1.1 version is from 1990, a few months after the initial 1.0 release. I know for sure it was sold in Europe around that time and it has copy protection. The manual was also smaller (only 6 pages) and was rewritten to just mention the IBM version, not the other commands or information (unlike the original manual that has references for IBM and Mac). In 1992, The Hit Squad rereleased that 1.1 version with just a small technical manual (same cover for different games, like Hook, etc) and removed the copy protection... There's info about it on the original Hit Squad manual where they mention that they removed the copy protection scheme. You can even find pictures of all the different versions on mobygames under Prince Of Persia DOS! I think replacementdocs has a few scans of all the manuals (not sure if they have the Hit Squad IBM version one but the Atari/Amiga one they have there is pretty much the same...) When playing the original 1.1 version uncracked, all the copy protection questions refers to just 6 pages, instead of 12 or 13, so the letter answers are very different. I typed a small list of all the 40 passwords for version 1.1 and i'll double check it if i find the original manual on ebay or something... The Hit Squad disk you attached is exactly the same i have with protection removed (even filedates are the same). In the meantime, i'll upload my disks here (all in the .ima format) along with the original unmodified version of POPTRAIN and the french version of POP 1.0 (Germany got the 1.1 version only but i don't have that one).

Who else might know the origin of that POP2 1.1 demo?

[Norbert]

Who else might know the origin of that POP2 1.1 demo?

Maybe Jordan Mechner...
You could Tweet him or use the e-mail address mentioned on his website.

[David]

In the meantime, i'll upload my disks here (all in the .ima format)

Ah, so there were one-disk and two-disk versions.
I remember someone said that if a file is missing, the game may ask for either just a disk, or disk 1 or 2, so there must have been two versions of the game.

According to the disassembly, at startup the game checks if kid.dat exists. If it does, it assumes that you're running the one-disk version. Otherwise it assumes you're running the two-disk version. (In the two-disk version kid.dat is on disk 2, but prince.exe is on disk 1.)
The game also has a table that stores which file is on which disk in the two-disk version, so it can ask for the correct disk.

[DoutorHouse]

In the meantime, i'll upload my disks here (all in the .ima format)

Ah, so there were one-disk and two-disk versions.
I remember someone said that if a file is missing, the game may ask for either just a disk, or disk 1 or 2, so there must have been two versions of the game.

According to the disassembly, at startup the game checks if kid.dat exists. If it does, it assumes that you're running the one-disk version. Otherwise it assumes you're running the two-disk version. (In the two-disk version kid.dat is on disk 2, but prince.exe is on disk 1.)
The game also has a table that stores which file is on which disk in the two-disk version, so it can ask for the correct disk.

Thanks for that interesting information! I confess i know absolutely nothing about programming but i've always been aware of different file sizes for every install.exe. I noticed the install.exe for every two 5.25" disks version has always 32 more bytes than the install.exe file for the one 3.5 disk versions. What really has intrigued me is why the install.exe files for versions 1.0 and 1.1 don't work under DOSBox. I haven't tried them on a real DOS machine since the 90s but apparently the install.exe for version 1.3 works fine. Anything older than that doesn't.

Thanks again for the information! I hope my files are useful to you and Norbert and Merry Christmas to you both and everyone on the forums!

[David]

Thanks for that interesting information! I confess i know absolutely nothing about programming but i've always been aware of different file sizes for every install.exe. I noticed the install.exe for every two 5.25" disks version has always 32 more bytes than the install.exe file for the one 3.5 disk versions.

I just looked into them.
Where the 3.5" version says "Prince of Persia Disk", the 5.25" version has "Prince of Persia Disk 1" and "Prince of Persia Disk 2" instead.
Also, the 5.25" version contains the filename "Kid.dat". Probably the installer looks for kid.dat to check whether the user inserted disk 2.

What really has intrigued me is why the install.exe files for versions 1.0 and 1.1 don't work under DOSBox. I haven't tried them on a real DOS machine since the 90s but apparently the install.exe for version 1.3 works fine. Anything older than that doesn't.

That's odd. I mounted the image as A:, and an empty folder as C:. When I press enter on the destination path, the title bar changes from "Program: INSTALL" to "Program: DOSBOX", i.e. the installer quits without clearing the screen.
The oddest thing: If I type "cls" and enter, the screen is cleared. But I can't see "cls" when I'm typing it. Seems like the unexpected quitting leaves the screen in an unusable state.
Okay, I tried the installer in an unofficial version of DOSBox that can save the contents of the memory. ( http://ykhwong.x-y.net/ )
It shows me that the installer quits with an "integer divide by 0" error. But the error message is written onto page 2, while page 1 is shown!
With the debugger built into this special DOSBox, I could figure out what's wrong.
The installer checks the free space on the destination drive. DOSBox reports 262144000 bytes, which is too much for 16-bit arithmetic.
More precisely, the installer wants to divide this with 1024, but the result (256000) won't fit into 16 bits.
You can see the same number if you "dir" the contents of the C: drive.
Here is the disassembly for the curious ones: (comments by me)

Code: Select all

023F:0025  55                  push bp
023F:0026  8BEC                mov  bp,sp
023F:0028  53                  push bx
023F:0029  51                  push cx
023F:002A  8B5606              mov  dx,[bp+06]
023F:002D  80FA61              cmp  dl,61
023F:0030  7205                jc   00000037 ($+5)
023F:0032  80EA60              sub  dl,60
023F:0035  EB03                jmp  short 0000003A ($+3)
023F:0037  80EA40              sub  dl,40
023F:003A  B436                mov  ah,36 ; get disk free space
023F:003C  CD21                int  21    ; returns: AX = sectors per cluster (0x20 = 32)
023F:003E  2BD2                sub  dx,dx
023F:0040  3DFFFF              cmp  ax,FFFF ; FFFF if drive is invalid
023F:0043  740B                je   00000050 ($+b)
023F:0045  F7E1                mul  cx    ; CX = number of bytes per sector (0x200 = 512)
023F:0047  F7E3                mul  bx    ; BX = number of available clusters (0x3E80 = 16000)
023F:0049  BB0004              mov  bx,0400 ; divide by 1024 to get kilobytes
; now DX:AX = 0x20*0x200*0x3E80 = 0xFA00000 = 262144000
023F:004C  F7F3                div  bx
; the result would be 0xFA00000/0x400 = 0x3E800 = 256000 (kB), but it won't fit into AX, so a division by zero error is raised
023F:004E  EB03                jmp  short 00000053 ($+3)
023F:0050  B8FFFF              mov  ax,FFFF
023F:0053  59                  pop  cx
023F:0054  5B                  pop  bx
023F:0055  5D                  pop  bp
023F:0056  CB                  retf

And here is the checking of free space from the 1.3 installer:
The only difference is that there is no "div" this time.

Code: Select all

01A4:091D  55                  push bp
01A4:091E  8BEC                mov  bp,sp
01A4:0920  53                  push bx
01A4:0921  51                  push cx
01A4:0922  8B5606              mov  dx,[bp+06]
01A4:0925  80FA61              cmp  dl,61
01A4:0928  7205                jc   0000092F ($+5)
01A4:092A  80EA60              sub  dl,60
01A4:092D  EB03                jmp  short 00000932 ($+3)
01A4:092F  80EA40              sub  dl,40
01A4:0932  B436                mov  ah,36
01A4:0934  CD21                int  21
01A4:0936  2BD2                sub  dx,dx
01A4:0938  3DFFFF              cmp  ax,FFFF
01A4:093B  7406                je   00000943 ($+6)
01A4:093D  F7E1                mul  cx
01A4:093F  F7E3                mul  bx
01A4:0941  EB03                jmp  short 00000946 ($+3)
01A4:0943  B8FFFF              mov  ax,FFFF
01A4:0946  59                  pop  cx
01A4:0947  5B                  pop  bx
01A4:0948  5D                  pop  bp
01A4:0949  CA0200              retf 0002

I just love this kind of detective work!

Thanks again for the information! I hope my files are useful to you and Norbert and Merry Christmas to you both and everyone on the forums!

Same to you!

[DoutorHouse]

Thanks for the amazing detective work! I was thinking it might have to do with the reported DOS version on DOSBox but i always got the same result (the install.exe would quit) no matter which version i'd use. So, if those 1.0 and 1.1 files detect a much smaller disk size, they'll work fine, i guess.

I haven't contacted Mechner yet asking him about the location of the POP2 1.1 demo and i probably won't... I'll keep searching on old cds. There are lots of sites with cd images of old magazines disc covers (like Joystick, PC Gamer, etc).

[Andrew]

Speaking of PoP2, looks like there were two releases of PoP2 1.0 with the only difference being the Setup program.

Here's PoP2 1.0 with Setup 1.0:

Old_PoP2_1.0a.png (2.07 KiB) Viewed 8894 times

Old_PoP2_1.0b.png (9.17 KiB) Viewed 8894 times

And here's PoP2 1.0 with Setup 1.01 (note that the Windows 3.x accessibility option was removed):

New_PoP2_1.01a.png (1.97 KiB) Viewed 8894 times

New_PoP2_1.01b.png (8.59 KiB) Viewed 8894 times

Finally of course we have the drastically cut down Setup for PoP2 1.1:

PoP2_1.1a.png (2.03 KiB) Viewed 8894 times

PoP2_1.1b.png (4.37 KiB) Viewed 8894 times

I guess HiMem is automatically used if available, but wonder why they had to go and remove the Input Device option? This means the only way to enable a joystick with PoP2 1.1 (and PoP1 1.4 which uses the same Setup program) is from within the game itself.

[DoutorHouse]

That's very interesting. That version of POP2 with Setup 1.01 (with the Windows 3.x accessibility option removed) is from the 1995 compilation cd. That compilation was sold on cd-rom only and also had the complete 1.3 version of the original Prince Of Persia.

[Andrew]

PoP1 1.3's Setup lacks the accessibility option too (at least the version I have):

PoP1_1.3_Setup.png (4.58 KiB) Viewed 8877 times

I wonder if there was an older release of 1.3 with that option, just like there was for PoP2 1.0? PoP1 1.0 and 1.1 anyway never had Setup included.

[DoutorHouse]

I checked all the diskette versions of 1.3 and that option is never there, so, to the best of my knowledge, it was never there for POP 1.3...