THE ONE MEG COMMODORE: A User Review

by Dick Estel

After I had purchased my C64 in November of 1987, I read a book on buying a computer (I always
was a little backward). The book was out of date but highly entertaining; and in it the author mentioned
the lust for more memory. His system was up to 48K, but he was pretty sure he was going to have to
upgrade, although he was hesitant about whether he NEEDED more memory or just WANTED it.

When the C64 came out one of its selling point was the whopping 64K memory, unprecedented in an
affordable computer at that time. Now (1990) of course, anything less than one megabyte is considered
old fashioned by business or professional users.

We in the Commodore field left the 64/128K limit behind several years ago when CBM introduced the
1700, 1764 and 1750 RAM expanders. Now the megabyte barrier has been broken for Commodore,
thanks to a circuit designed by Andrew E. Mileski (Recursion on Q-Link).

A number of technically adept people have upgraded their own REU's to one, one and a half or two
megabytes. Two Q-Link subscribers have offered an upgrade service at prices starting at $60.

As soon as I could live without my REU for a few days, I sent it off to Raymond Day in Michigan; and
a couple of weeks later it arrived and was immediately plugged in for a test.

One of the limitations of this upgrade is that there are not many programs that allow you to make use of
the extra memory. However, for GEOS users, it is probably the ultimate, because it allows the use of a
1581 RAM disk.

To explain briefly, in GEOS the REU simulates a real disk drive. The amount of information that can be
copied into the REU is held within the limits of the existing drives that the REU can emulate-165K for a
1541 RAMDISK and 330 for a 1571. The maximum 512K memory of the 1750 (or its clones) allows
only the 1571 (the rest of the memory is used for some file handling and screen updating chores).

The expansion to one megabyte (1024K) allows for a RAM 1581, with 790K of usable memory. For
my usage, I have found the the 330K 1571 RAMDISK to be almost adequate. However, there are
often times I would like to have programs and data files available in RAM, but I run out of room. 

With the 1024 upgrade, I have loaded all the major applications (geoWrite, geoPaint, geoPublish), plus
many accessories, fonts, photo albums and data files, and have always had over 100K left unused.
With the 1581 RAMDISK, I can put all the files for an issue of the newsletter in the REU at once,
instead of doing it in three sections as I used to do. There is room left for several photo albums and
other miscellaneous programs that I can use, but could not make room for before. I used to think that
the 512K REU was heaven, so this must be Nirvana.  

The modification includes addition of a slide switch and two LED's, very neatly installed. The switch
allows changing back to a 512K REU for those programs that do not work with the expanded version.
For example, I have the Write Stuff configured to load the dictionary into the REU, but with it in 1024
mode, it would not work.

(From The Interface, October 1990, newsletter of Fresno Commodore User Group, via the
Commodore Information Center, http://home.att.net/~rmestel/commodore.html)