Structure

Before I get on to the method of transfer, let me talk a little about the structure of Infocom adventures. In other words, how does Infocom make its games so quickly for so many different computers at once?

Infocom authors always begin by writing their adventures for a "virtual machine," that is, a machine that does not exist in reality. I will refer to the code generated for the virtual machine as the data file. This data file is then transfered to the disk formats of the computers being supported.

Of course, the computers can't understand a word of the data file in itself. So the authors make for each machine a "driver program," designed to interpret the data file and translate it to the machine on which the adventure is to be used. The authors only have to make this driver file once, as long as they don't want to change virtual machines. So, to make a new adventure, all they have to do is transfer the data file to a disk format and the driver program to the same disk.

The method presented here is based on the fact that the data file, with a few exceptions, is always the same file, no matter which computer format it is on. Only the driver programs vary from computer to computer. So, if one has the driver program for a now-abandoned computer, and one finds a way to copy the data file over, one then has a version for his or her computer!

TRANSFERING TO MODEL 111/4

Model I users please be patient. I'll get to you soon enough. Read this section, however, because some of it applies to you.

The first thing one needs to run an adventure on the Model III or 4 (III mode only) is the driver program. Because the driver for these computers is the same on all TRS-80 Infocom adventures, any of them will do. The driver program is recognized by a /CMD extension on the name. For example, the driver for Hitchhiker's Guide to the Galaxy is HITCHHIK/CMD (and the data file is HITCHHIK/DAT, but we'll worry about that later). Transfer this driver to a blank, newly-formatted diskette, which may have a bare DOS on it as well.

This driver program knows which data file it is looking for by checking its own name, then sticking /DAT on it. So you will need to rename the driver to whichever game you are planning to transfer. For example, on Leather Goddesses of Phobos, you should rename your /CMD file to LEATHER/CMD.

Now comes the hard part. You need to find a disk format where the data file is easy to get at and transfer. Fortunately, Infocom is starting to take the copy protection off its games, so that the data files are visible from the directory and accessible by normal methods. The IBM version of LGOP is an example of a non-copy-protected disk with a visible, accessible data file (named LEATHER.DAT).

After you buy (yes: BUY; see A NOTE ON PIRATING) this version, you will need to transfer it from the foreign disk format to your own. Hypercross or Super-Cross/XT may do the trick, or even TRSCROSS if you happen to have an IBM handy. However, if you don't like buying software-translation programs and don't know how to do it yourself, you can use an RS-232 link between a friend's computer and your TRS-80. Name the file the same as your driver program except a /DAT extension. At 1200 baud, it usually takes 20-30 minutes to transfer the data file, meaning 80-120 minutes at 300 baud or 10-15 minutes at 2400. If you have a null modem and the computers right next to each other, you should use 9600, which means the file will be transfered in less than five minutes. 19,200 baud rarely works out.

Once you have the /CMD and /DAT files, you're almost set. But wait, there's one more thing. As a form of primitive copy protection, the /DAT file must have a password on it or the program will bomb out. This password is "SMC." An example command under TRSDOS 1.3 to assign this password to LGOP would be:

ATTRIB LEATHER/DAT (ACC = SMC,UPD = SMC,

Do NOT put the password on the driver program.

Now type the filename of the driver program to execute. Tah dah! A program in TRS-80 Model lli/4 format!

One note: to the best of my knowledge this will not work on Infocom's "Interactive Fiction Plus" stories, even if you have 128K! Infocom's decision to drop the TRS-80 series came before A Mind Forever Voyaging, so a TRS-80 Plus driver was never made. You can write a nasty letter to Infocom if you like, but I doubt it will do any good. Or, if you want a challenge (and I am talking CHALLENGE), you can try to make a Plus driver yourself. Don't get your hopes up on getting any help from Infocom, though.

0 0

Post a comment