Type I, II, and III PC Cards (aka PCMCIA, CardBus, etc)

I have an older PowerBook, a “WallStreet”, which happens to be the last of the Apple PowerBooks to sport two PC Card slots. Beginning with the “Pismo”, they started saving vertical space by only providing a single card slot. (I haven’t paid much attention to PC laptops so I don’t know if the same is true for them as well or if two-slot models are still common).

Now, in the modern PowerBook specs, they usually express it as “accepts one Type I or Type II card” and since the single card goes in the single slot no one cares if it is a Type I or a Type II. But for my older model, the phrase was “accepts two Type I or Type II cards, or one Type III card”. And I have one of those critters, an ixmicro Road Rocket external display card. It’s a thick sandwich of a card and does indeed fill up both slots although electronically it only connects to the connection pins of the lower slot.

I just bought a new display card because ixmicro went out of business before the MacOS X era, so there is not and presumably never will be a MacOS X native driver for the Road Rocket. To that end, I bought a Village Tronic VTBookDD external display card, and like all modern cards it only takes up one slot (I don’t know if it is a Type I or a Type II). Well, it works, but compared to the old Road Rocket it’s a dog. The Road Rocket eats it for lunch on graphics benchmarks, sometimes throwing up more than 50 times as many megapixels per second as the VTBook.

Question: is this just shoddier engineering on the part of VT, or does (did) the Type III specification allow a card to pull twice the power of a Type I or II and that’s why the Road Rocket kicks butt?

And just for the heck of it, as long as I’m asking, what’s the diff between Type I and Type II?

Link

The differences between the different types is physical size. (http://www.pcmcia.org/faq.htm#types) Type I cards are primarily used as memory cards, and are thinner than a Type II (without the thicker middle section). I have a few that I use with my Newton.

I should not have mentioned Type I versus Type II, since that confuses the issue. Let’s concentrate on Type III versus Type I or Type II. I was already very much aware that there’s a difference in physical size, as a Type III card takes up both slots whereas each slot can accomodate a Type I or Type II by itself.

So visualize a peripheral-equipment engineer saying, “Hey, let’s make this one a Type III card! It can be a big card! It can take up two slots instead of just one! That would be so cool”

Presumably not. My question is, what are the trade-offs? What do you get, advantage-wise, if you produce your card as a Type III card? And why not make them in such a way that access to the other card slot is not blocked? And does the significantly more impressive performance of my Road Rocket Type III display card when compared to the newer VTBook Type II display card in any way illustrate this tradeoff, or would it be just as easy to release a high-performance display card that only used up one slot?

::deciding that the lack of responses is probably due to hamster timeout (it still shows up as having 2 replies the last of which is by Cleophus when viewed from the list), I bump::