The Fitting Room
The RAM Thing
The RAM Thing
Mike Jewison, AC Staff Columnist
We've got a lot of stuff to cover this time, so let's get right to it. If you remember, I was looking for a memory upgrade for my 800XL. Not knowing a lot about the available upgrades for the XL I started browsing the literature for whatever RAM upgrade gems I could dig up. (After my experiences from last time, I decided to stay well away from any online service!)
Thanks For the Memory!
Probably the best-known of the XL memory upgrades is the RAMBO XL, from ICD. Unfortunately, ICD dumped support for the 8-bit Atari computers begining 1992- to the chagrin of many of us- with the result that RAMBO is difficult, if not impossible, to find anywhere. Although it was not completely 100% compatible with the extra memory in a stock 130XE, it did support BASIC XE's extended mode as well as RAMdisk handlers with Atari DOS 2.5, SpartaDOS, and MyDOS (and probably others, as well). It was also relatively inexpensive; $39.95 not including the necessary RAM chips. At the risk of sounding nostalgic, I remember when I purchased a 48k memory card for my Atari 400 way back in 1982. It cost me almost $400.
Computer Software Services, a company of which I am particularly fond, offers their Power Plus 256K memory upgrade for the 800XL for $99.95. CSS claims this upgrade is the most XE-compatible available for the XL. Compatibility is an important issue for me, but it's not worth $100 (not in my opinion, anyway). The advantage to the Power Plus is that if you send in your computer CSS will install the upgrade at no additional cost. This can be a boon if you happen to be all thumbs with a soldering iron.
Newell Industries offers a variety of upgrades, including a 1-meg behemoth. [Editor's Note. I just installed one of these in an 800XL a few weeks ago; it's awesome! -BP] One problem with this gigantic upgrade is that in order to use it you end up rendering the internal BASIC inaccessible from software. You can still gain access to it by wiring the BASIC enable line to an external switch and then boot with BASIC on or off, depending on the switch setting. I like the idea of having internal BASIC accessible from software (call it personal bias), so even though the idea of a monster RAMdisk is extremely appealing, I decided against it. Newell does offer a smaller 256k upgrade which is available from American Techna-Vision for $27.50. By the time you add in the cost of the 256k RAM chips you're looking at a total cost of around $47.50. I thought this sounded like a pretty good deal, but I kept poking around to see what else I could find.
I happened to be looking through my Best Electronics catalog shortly thereafter when I noticed something called the Wizztronics 256k memory upgrade. The bare board was just $11 and Best was offering the RAM chips for $14. There were a couple of other components which needed to be mounted on the board, but they came to just a couple of dollars. So for roughly $25 I could upgrade my 800XL to 256k. I started thinking that there must be something wrong with this. Why was it so cheap? I called up Brad Koda, owner of Best, and asked whether or not he knew if MyDOS and/or SpartaDOS would properly recognize the Wizztronics; unfortunately, he didn't. So I threw caution to the wind and ordered all the components there on the spot, thinking that if it didn't work I'd only be out $11, because the RAM chips could probably be used in some other (more compatible) upgrade. About a week and a half later, the package arrived.
Resistance is Futile
The documentation for the Wizztronics, affectionately known as "The Wizzy", is scanty at Best (pun intended). A single sheet of paper accompanied the board indicating the connections between the Wizzy and the motherboard. The first thing you do is to pry the 64k RAM chips and replace them with the newly purchased 256k chips. The Wizzy plugs into a socket near the RAM chips via a double-sided header. There are either three or five components (TTL gate chips) which are inserted on the Wizzy board depending on the exact version of your Antic chip; I used sockets rather than soldering the chips directly to the board. You'll also need some scrap wire to make five connections between solder pads on the Wizzy and five pins on the 6520 PIA as well as one additional connection between the Wizzy and the motherboard. Since I hate soldering anything directly to a pin, I took a pair of tin snips and cannibalized a chip socket to give me five inline pins. I then soldered the five wires from the Wizzy to the hacked socket pins and plugged the PIA into them. This also makes for a real quick deinstallation should I ever decide to remove the Wizzy.
Everything was installed, save for one component, and it was here that I ran into a problem. The printed instructions call for a 33-ohm resistor to be soldered onto the Wizzy board. Hand-scrawled on the instruction sheet was a notation that resistor R32 on the motherboard is a 33-ohm resistor and this resistor must be removed in order for the Wizzy to function properly. (R32 sits immediately behind the bank of RAM chips.) The logical thing to do, then, was to take the resistor which had just been removed from the motherboard and insert in onto the Wizzy. The only problem is that when I looked at the resistor I'd pulled, it was 3100 ohms- not 33! So now I was in a bit of a dilemma. The printed instructions said to use a 33-ohm resistor, but the hand-written note told me to use a 3100-ohm resistor pulled from the motherboard. With great trepidation I decided to follow the hand-written instructions and use the one I'd removed from the motherboard. Big mistake.
When I finished the installation, I powered the computer up (without the disk drive) and was greeted with the U1traSpeed+ OS's information screen. (The U1traSpeed+ is a replacement OS module for the XL/XE computers, available from Computer Software Services.) The US+ includes its own set of test utilities and I figured I should probably use those to test the machine, particularly memory. First off, I knew I had a problem - the US+ thought I was running a 192k machine, not 256k. In a valiant attempt to rationalize this, I thought that perhaps this number referred only to memory above the stock 64k. As I started the tests to check RAM bank by bank, it was clear something was wrong. The OS would get into the first bank of 16k and spit out an error message. Every time. I consulted with a couple of people and decided to remove the 3100-ohm resistor from the Wizzy and replace it with a 33-ohm unit. I made the change and powered it back up again.
This time, the US+ told me I had a 256k machine. And the RAM tests turned up no errors at all; all 12 banks of extended memory passed the various checks with flying colors. Hot dang - it worked!
Upon further consultation with assorted gurus and Alchemists, I decided to perform a little experiment; I reinstalled resistor R32 to its original location on the XL motherboard. This resistor, I am informed, is a pullup resistor for the REFRESH line on the RAM chips and one of its functions is to reduce ringing and help stabilize operation. One or two people told me that it should not be necessary to remove it from the motherboard to have the Wizzy perform properly. You know what? They were right! With R32 back in place the upgrade performed just as it had with no resistor.
So why didn't the upgrade work with the 3.1k ohm resistor on the Wizzy board (rather than the proper 33 ohm)? Our best guess is that the value of this resistor is so high that it's probably dropping the signal voltage when the REF line is pulsed. Needless to say, the last thing you need with RAM chips is to have the signal voltage drop. Depending on the amount of voltage reduction, the RAMs may or may not get refreshed; the result is something resembling the HAL 9000 at the end of "2001: A Space Odyssey" (i.e. real screwed up).
Now that I had a functioning memory upgrade installed it was time to test it out. I had three criteria the upgrade had to pass: it had to function properly as a RAMdisk for (a) MyDOS, (b) SpartaDOS (both 3.2 and the X-cartridge), and (c) the U1traSpeed+ OS RAMdisk handlers.
To make a long story short, I was able to successfully create usable RAMdisks with all three of the DOSes mentioned. The RAMdisk created with SpartaDOS-X is 16k smaller than the others (176k vs. 192k) because SDX reserves a 16k bank of memory for its own nefarious purposes.
The final test to run was to check the RAMdisk handlers with the US+. I had no reason to doubt that it would work, particularly since the US+ was able to earlier recognize the fact that I had a 256k computer. As you will undoubtedly remember, I was planning on using the US+ to install the RAMdisk as drive 1 and run my beloved Infocom games from there, speeding up the games and saving wear and tear on my now ancient Percom disk drive. In order to accomplish this, however, there were a number of preliminary steps I had to perform:
1.) Get into the US+ menu and install the RAMdisk as drive 1 and the Percom as drive 2.
2.) Use the US+ sector copier to copy the game data (side 2 of the disk) from floppy to the RAMdisk.
3.) Temporarily boot from drive 2. This allows the computer to boot from a drive other than drive 1.
4.) Once prompted to flip the disk, hit CTRL-SHIFT-6. This restores the drive configuration to the US+ settings (in other words, the floppy becomes drive 2 again). When you press RETURN at this point, you are into the game with all disk access now occurring from drive 1 (the RAMdisk).
I played Enchanter (one of my favorites) for about an hour and was able to get much farther into the game than I normally could in a one hour session. Needless to say, I was ecstatic that the memory upgrade had met all my criteria. I then decided to try a little experiment. I made a list of 20 commands (usually the first 20 things I do when I start Enchanter from scratch) and timed how long they took. When I ran the game from the floppy, it took about 115 seconds; from the RAMdisk that number was reduced to 90 seconds. If you consider that I likely spent about 50 to 60 of those seconds typing in the commands, the true increase in speed resulting from the use of the RAMdisk is on the order of 2 to 3 times. Applications such as database programs, which can be very disk intensive, will likely see even greater gains. With this kind of increase in productivity, I'm looking forward to trying out a number of other applications and games with my US+/RAMdisk combo.
Go Ahead, Make My Day...
So what are we left with here? Now that the dust has settled, it would seem the Wizzy is a direct replacement for the recently departed RAMBO. And not only is it a replacement, but a much less expensive one at that. [The Wizztronics upgrade is actually a bare-bones RAMBO "clone" which, like RAMBO, traces its origins to the article published in BYTE magazine in 1985 by Claus Bucholz. - BP] Keep in mind, though, that if you decide to install the Wizzy yourself there are a couple of errors on the installation sheet:
1.) The resistor to be installed on the Wizzy daughterboard should not be taken from the motherboard. Regardless of what's written on the instructions, R32 is NOT a 33-ohm resistor. Find a proper 33-ohm resistor from another source to use with the Wizzy (Radio Shack part #271-007, 29 cents/pkg. of two).
2.) Do not remove resistor R32 from the motherboard; it's not necessary. Any time you can perform an upgrade without having to remove something, you have simplified it by an order of magnitude!
That said, I heartily recommend the Wizztronics 256K. I've been using mine for the better part of a year and, since the initial installation, haven't run into any problems with it.
Rats. Now that I think of it, it wasn't Rambo who said "Go ahead, make my day", it was Dirty Harry. Sigh. I need a vacation!
Next time: Christmas comes to the Fitting Room. In June???
Wizztronics 256k Upgrade Best Electronics San Jose, CA
U1traSpeed+ OS Computer Software Services, Rochester, NY 14617 U.S.A. (716) 429-5639 $69.95
Note on 256K RAM chips: the type of chip used in all 256K upgrades is the 41256 dynamic random access memory (DRAM), a 16 pin DIP that's pin-for-pin compatible with the original 4164 (64K DRAM) chips in your stock machine. If you do any kind of RAM uprade, don't trash your original 64K chips; it's a real good idea to hold onto them. Prices on 256K DRAMs are now down to about $1.25 each-or less-depending upon the "speed" of the chip. Speed is measured in nanoseconds (nS). The faster the chip, the higher the price. Typical speeds are 60, 80, 100, 120, 150, and 200nS. Fortunately, Atari 8-bit upgrades work best with the "slower" (cheaper) chips in the 100-150nS range; the 200nS chip- if you can find one will probably work but might lie on the cusp of reliability. The faster chips-below 100ns-will also work but gain you nothing except to waste your money; prices on those can range beyond $2.00 each. Checkout an issue of Computer Shopper magazine ($2.95 off the rack at most US outlets; also available in Canada and the U.K.) If you really want the low-down on latest prices. -BP