Password cartridge

By mars2000you

Enlighted (6561)

13-09-2015, 23:24

How is supposed to work the Password cartridge extension on openMSX ?

I guess it needs to be used on a MSX2 or higher machine without using of the SET PASSWORD command, but then I don't see the computer asking me a password.

Or maybe it needs to be used otherwise ...

By mars2000you

Enlighted (6561)

13-09-2015, 23:56

When I read the comments on this page, I guess that the openMSX team does not really know the practical utility of this extension :

http://sourceforge.net/p/openmsx/mailman/message/10789891/

After 8 years, it looks like that Manuel does not still have received an answer to his question !

By Manuel

Ascended (19679)

14-09-2015, 00:05

I don't think it has the purpose to ask for a password at start up.

I think it's more used as a kind of protection cartridge. So, you could write a protection scheme in your software that checks whether it reads the proper stuff on the password cartridge. But this is just my guessing. I'll try to check with BiFi (who implemented it) too.

EDIT: ah, right... you mean https://github.com/openMSX/openMSX/issues/159 I forgot that there was a ticket of it... anyway, this doesn't conflict with my theories I wrote above :)

By mars2000you

Enlighted (6561)

14-09-2015, 00:03

Something like the ARC cartridge, but less complex ?

By zeilemaker54

Champion (355)

14-09-2015, 19:07

Manuel wrote:

I don't think it has the purpose to ask for a password at start up.

I am sure it does:
http://msxsyssrc.cvs.sourceforge.net/viewvc/msxsyssrc/base200/subrom.mac?view=markup, line 5189 onwards (storing keycard password in clockchip) and line 5482 onwards (handling stored keycard password in clockchip at system startup)

By mars2000you

Enlighted (6561)

14-09-2015, 19:42

So, it corresponds to what I can read in the PORTAR document about the PASSWORD string :

"type 1 is stored in form of a 16bit CRC together with an optional 'key cartridge value'."

http://problemkaputt.de/portar.htm#realtimeclock

By Manuel

Ascended (19679)

14-09-2015, 20:50

Oh, definitely looks like it, zeilemaker54!

By mars2000you

Enlighted (6561)

14-09-2015, 23:33

It looks like that the last byte in the RTC needs to have a value different from 00. In this case, the computer will read the optional 'key cartridge value' (a 16 bit password) via I/0 port 7F and compare it with the contents of the 4 previous bytes.

I guess this hardware option was used for very long passwords (until 255 characters !) on professionnal MSX computers.

By Manuel

Ascended (19679)

14-09-2015, 23:22

255 chars?? Where did you read that?

By mars2000you

Enlighted (6561)

14-09-2015, 23:24

It's in the MSX2 documentation. Only TITLE and PROMPT are limited to 6 characters.

By mars2000you

Enlighted (6561)

14-09-2015, 23:46

Precision ; it's not the last byte in the RTC, but the last byte really used by the RTC for the password.

In the openMSX cmos file, it should be #2F that should have a value different from 00 to make work the 'key cartridge' option.