Re: [NTLK] Newton Card Terminology question

From: Paul Guyot (pguyot_at_kallisys.net)
Date: Fri Nov 08 2002 - 10:37:30 EST


>I see the terms linear and ATA. What is the difference?
>
>I have read the FAQ and the page on memory cards
><http://www.mac3.de/sig/newton/memory_cards.html> and functionally I
>guess the only thing I need to know is that if I want to use my
>Compact Flash cards with a PCMCIA adapter I need Paul's driver. Is
>there anything else worth thinking about for this 2100 newbie?

Well.
ATA and Linear are two different technologies.

Linear is called like this because to read a linear card, you just
need to do as if it was some random access memory (RAM). There are
various ways to write to them, and the MP2100 can handle the two most
common technologies (Intel and AMD). You alread know the best website
about linear cards on the Newton.
The main limitation of these cards is that they cannot be larger than
64 MB. There are larger cards (128MB), but they're not compatible
with the Newton.
NewtonOS can handle linear cards natively. It means that if you
remove every software on your Newton, you will still able to insert a
linear card and get data on it (for example restore a backup)

ATA cards are called like this because they use the ATA technology.
This is the technology used in most hard drives (the other technology
is SCSI).
The Newton cannot handle this kind of cards natively and you're right
that you need ATA Support to use them.
Please note that ATA Support isn't just an ATA driver. It's an ATA
driver plus a store engine (an object database). NewtonOS built-in
store engine can only work with linear cards and it is limited to 64
MB. I think that the Newton will accept to use a 8 GB ATA-based
store, although this hasn't been tested yet as there isn't any disk
large enough. And the limit might actually be 64 GB.

The main other difference is price. *New* linear cards are very
expensive. Check timasci.com. 4 MB AMD is 46.5 USD. There are other
sources for cheaper linear cards. Someone was selling 32 MB cards
here.

Another difference is the size of blocks. Blocks on linear cards are
64 KB while they are 0.5 KB on ATA cards. Also, NewtonOS doesn't
handle defects (dead blocks) in linear cards at all. ATA Support
doesn't handle dead blocks completely either, but this is very likely
to change.
In any case, if a block died, you will lose data (that was on it,
obviously, but sometimes more because there are dependencies between
blocks).

Finally, ATA Support is a little bit slower than linear cards when
you have a fast ATA card. This is very likely to change as well.

Paul

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