“SLAM” RAM Expansion for the Amiga 1000

[intric8]

Sometimes the love never stops. You know, where modern hardware upgrades are still being invented for computers long since left behind by the vast majority of humanity. It's amazing!

Recently site member Crispy informed me he was going to create a RAM expansion specifically designed for use with his reverse engineered Microbotics Starboard2 StarDrive R2 (whew!).

This is an original Starboard with SCSI support, RTC and extra fast RAM (1-2MB).

The idea was to take advantage of the pass-through port on the original Starboard and provide Amiga 1000’s with up to 8 MB of modern SDRAM, similar to what David Dunklee’s Parceiro provides.

After weeks of work and effort, Crispy finalized what he calls SLAM: the Supplemental Legacy Amiga Memory board.

When I got one in my hands, I could quickly see why Crispy decided to not simply recreate the “Upper Deck,” which was a 1-2MB expansion for the original Starboard2 that fit inside the original housing. This design wouldn’t have fit inside the case.

SLAM board for the Microbotics Starboard (or other devices).

The Hippie Campus sounds like Berkeley, amiright? ;)

No, it is specifically designed for the pass-through port. And this gives it the added value of being paired with non-Starboard autoconfig expansions smaller than 8MB should one so choose, which is a great idea and provides a lot more flexibility.

It’s worth pointing out that this RAM board is not auto-config. It was built this way for multiple reasons, the most obvious being cost.

You must manually configure the hardware memory size and location before it can be used.. You do this by setting tiny little physical dip switches on the board.

I needed to break out my jeweler's glasses and dental picks to set these little guys. Finger added to establish size. Holy crap... I need to clean my keyboard!!

In order to do it correctly, I simply followed along Crispy’s impeccably well-written and easy-to-follow instructions. Honestly, if I can do it anyone can.

Crispy's included Help Docs are some of the best written instructions I've ever seen. You get a very good and thoughtful education while also learning about how to install your hardware.

From Crispy’s instructions:

“In order to correctly configure the board you must know the size and location of all the autoconfig expansion memory in your computer. This information can be obtained by using SysInfo.”

He then walks through several common examples and how to set things up accordingly.

After configuring the board you then need to install a very small custom program he wrote and put it in your C directory - on your hard drive - to “see” the RAM on boot up.

Crispy continued:

When the SLAM board is plugged into the expansion port, it is always enabled and active when the computer is on. This differs from auto-config memory boards because those boards are initially disabled at power-on and at reset, and remain disabled until the OS enables them after it has completed its very early startup tasks.

Even though the SLAM is always fully active, the OS has no way of knowing about it since the SLAM board does not provide the hardware signaling that auto-config boards use to make themselves known to the OS. This is where the slam tool comes in.

The slam tool is used to tell the OS how much memory the SLAM board has, and where in the expansion memory address space it is located. It should be placed in the C: directory, and then called from the Startup-Sequence.”

Bonus Power

Crispy:

“The slam tool provides an option for creating a resident module that will automatically add SLAM to the system memory list whenever the computer is reset. This option is useful in cases where you reboot your computer from a disk that doesn't run the slam tool, such as a floppy disk that contains a
game.”

In other words, if you have a game that only works via boot-up (therefore bypassing your hard drive under normal circumstances) you can boot the machine using the -r option for the slam tool. Then, when you reboot the computer the OS will know about the memory, and the game will be able to use it as your machine reboots. Super cool!

So my main issue at this point was what to do about an enclosure.

I didn't want the RAM just hanging down the side of the Starboard like that. I then remembered I had a spare case from a very early (broken) Starboard. The original Starboards were not expandable, and were only made to house large RAM boards. You can tell how to spot those by the case, which has large vents in the back and no slot for a SCSI ribbon cable.

I'd peeled the Microbotics sticker off of it a while back and given it to a friend who wanted one for his own Starboard. Regardless, I pulled out the case and took a look. One of the metal brackets was ripped off and some of the metal was warped, but otherwise it looked pretty good.

The saddest looking of my Starboard cases I had in a small pile.

It just so happens that - in an incredible stroke of pure chance - one of the holes in the SLAM's PCB was exactly where it needed to be for me to mount it inside the case!

I added a thin layer of anti-static between the SLAM and the case to prevent a possible short.

I may drill a hole in the back of the case for the other side so I can mount the SLAM totally solid.

The case now housing the SLAM was borderline junk. Now she's back on the desk and looking mighty fine!

Not 100% satisfied, I've decided to design a replacement sticker. I decided to leverage the shapes and angles of the original Microbotics logo to create my own "SLAM" version in a style I'd hope those folks would approve of if they saw it today. (At least, after the shock passed of wondering if we were all crazy! Hah!)

Now I need to get one of these printed... and will likely have 99 of them left over. Anybody else want one?

Note:
There are no plans to produce or sell these boards. However, Crispy is planning on releasing the Gerbers soon so others can follow in his footsteps should they want a SLAM for themselves.


Meanwhile, in Crispy's mad scientist Amiga lab...

BTW, I'm running 3.1 on my A1000 right now with the 3.1 ROM loaded into the upper 512K of SLAM.

Update:
Crispy has released the gerber files to the public.

[obitus1990]

Looks great. I'd recommend against using the anti-static bag as insulation, because in reality, it is a conductor. It acts a a Farraday cage to protect a board that is encased inside of it, hence the anti-static capability. But, anything placed outside and on top of it is potentially subject to electrical damage.

[intric8]

Thanks for the comment, Obitus. I'll swap it out with some thin plastic or cardstock - whatever I find lying around that doesn't angle it much.

[intric8]

I swapped it out with a nice construction paper instead. Should be good to go.

[A1-X1000]

just beautiful stuff man it brings me to tears! NEVER too much LOVE for our beloved Amiga 1000's eh

[intric8]

My stickers came in. I was able to do a minimum print of 10, and I wound up with 12 in the bag I received today. So, 2 quickly became sacrificial lambs in my initial cut-out tests. I had to use an X-acto so I wanted to do a couple test runs first.

I also had to use Goof-Off on the metal case to remove the original sticker residue. I went ahead and cleaned the entire case while I was at it with Windex. Yikes! It was a lot dirtier than I was expecting. Beige kinda hides that stuff, apparently.

The stickers came in like this:

The smallest sticker size they'll print is 2x2". The sticker is only supposed to be 22mm. So I put it directly in the center of a 2x2" square realizing I'd have to cut it out by hand when it came in.

After finding the center point on the back, I simply drew the 22mm box on the back. I also ran to the hardware store to buy a brand new box of blades. I have a metal ruler I've had for decades that also came in handy.

Pretty soon, I had the sticker in the proper alignment and slapped it on. I used this see-through ruler to make sure my lines were in fact as straight as I could get them.

At first blush, I was really pleased with how it turned out.

After popping it on the side, it quickly became apparent that my blue printed much darker than the original, which was a bit of a surprise.

In fact my sticker's blue is much closer to the Microbotics packaging.

All in all, the shade of blue doesn't bother me because the contrast is pretty significant. I think if mine was really close, but just a touch off, it would actually bother me a lot more. As it is, this looks pretty bad ass, don't you think? Not bad for an old beat up metal case that had basically been reduced to junk in the horde pile.