Well, according to "Mapping the Commodore 128", you have all the right locations.  In depth description of $121B-$121F says:
     This five-byte are holds the seed value for BASIC's random-number-generator routine ($8434).  When a positive argument is supplied, the RND routine generates the next random number by performing calculations and manipulations with the value here.  The generated values aren't really random--any given seed value here will always produce the same result.  However, the process is sufficiently complicated that the results aren't easily predictable.  Whenever any random number is generated, the resulting value is stored here for possible use as the seed for the next random number.  Location 4635/$121B is initialized to 0/$00 during the BASIC cold-start routine.  That is a change from previous Commodore models, where all five bytes of the seed value were initialized.  The zero byte has the effect of making the initial seed value 0, so the first random number value generated after the computer is turned on or after a reset will always be 1.07870447E-03.


      On an extra note, I had always read that the better way to get a truly random number was to read a value from higher in RAM; I think from the sound area, but not sure.  Hope something here helps you out.

    Sounds like too much work; there was an article in an old Run magazine or something that told how to add more colors using a software method.  Not sure where you would find it now, though, but it is possible.

     Well, I still have the C128D available, with keyboard, no box.  Havent' found extra software I had available to go with it, but know I have 2 expansion units and the 1351 mouse.  As far as GIVING it away, I think it has a good home, but would be willing to accept a fair price for it if shipping at least was paid for up front.  Not sure I want to go as far as to put it on eBay, would rather sell it to someone here who would (apparently) use and appreciate it.  I'm pretty sure I have an extra set of CPM disks for it and might include the parallel printer cable I got for it if the price was fair enough.

     Just curious, but did you know that the Pascal program for the C128 already allowed for graphics in C128 40/80 column mode?  I mean, why the extra work to get it done from the z80 chip?

    Incidentally, I used a special ribbon cable to connect a parallel printer.  Was more interested in the extra font and print speed capability at the time.

   Have found now that I can get more bang for the buck ($0.00) out of the altairz80 package in linux; all old software works and runs with speed.  At least, I've tried the dbase 2.43 package and the Wordstar; both run fine and quickly.  Have both for my old C128, down in the basement somewhere, along with books & docs.  Looking at them, I don't see much use for them anymore.  May play with dbase a little at some point just for old times sake.

     Originally, CPM offered better productivity tools than the C128 had.  For example, dBase 2.43 was available for the CPM mode.  Wordstar was available also, and configurable, wouldn't be too surprised but what it could be used with a modern printer.  I used it with a parallel adapter cable on a dot matrix printer that offered different fonts - aside from the possibility of having the bold, italic, underlining, etc. that was available in C128 mode.  There was also a spread sheet I never did use (but have anyway somewhere).  All these are available now on the altairz80 CPM site.
     It was always slow, and not much of a gaming computer.

     Any interested, found link at http://www.cpm8680.com/cpmc64/index.htm that includes ctools.

  Hi!  Just found this the other day and wondering what's up.  I have an old C128 and a C128D in my basement; believe the C128 is the one set up right now.  Have old programs, but the color is off on my monitor, so many of the games don't show well and 80 column mode didn't seem up to par last time I turned the whole thing on.  Seems like people on this board are still using these old computers, wondering what the going rate is?  I am in Colorado (USA) and willing to sell one of these if worth while.  Also wondering, though this may not be the best place to ask, what are you using on these nowadays and how well does the Vice emulator work for this?