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From: jb10320@uxa.cso.uiuc.edu (Desdinova)
Newsgroups: comp.sys.apple2
Subject: Re: DMA, SCSI and $C1 filetypes questions
Message-ID: <1990Oct18.193321.11984@ux1.cso.uiuc.edu>
Date: 18 Oct 90 19:33:21 GMT
References: <1990Oct18.171229.15406@uokmax.ecn.uoknor.edu>
Sender: news@ux1.cso.uiuc.edu (News)
Organization: University of Illinois at Urbana
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In article <1990Oct18.171229.15406@uokmax.ecn.uoknor.edu> cmparris@uokmax.ecn.uoknor.edu (Chris Michae Parrish) writes:
>I am planning on buying a new hard drive and either the RAMFast or apple's 
>new SCSI card.  What I was wondering is do I have to have a DMA memory card
>in order to use either of the new SCSI cards?  I realize that it won;t be as
>fast without DMA, but will they still function properly with the plain ole
>apple expansion card?  

The Apple Expansion Card *IS* DMA compatible.  As a general rule, a memory card
is DMA compatible if it has not more than four banks of RAM, whether 4 rows
of 8 chips or 4 SIMMs or whatever.  Applied Engineering has used a few tricks
to get their 6-row cards to be DMA compatible (GS-RAM, GS-RAM plus)

>My second question is wheter or not most of the available DMA cards that use
>SIMMS, use the same SIMMS found in most macintosh models?  I have access to
>about eight 256K SIMMS, and it would be nice to get a card that use them(
>They came from a Mac SE and a Mac II).

I believe the GS Sauce can handle 256K SIMMs, but you'd probably be better
off buying brand-new 1Meg SIMMs. They're only $40 these days, and getting
cheaper all the time.  You'd have to trash your 256K SIMMs if you wanted to
expand past 1Meg anyway, so you might as well get the 1Meg now.

>Lastly I was wondering if anyone could tell me the format of $C1 type pictures.
>Like for insstance where is the palette infomation, and where is this information supposed to be placed if you where to bypass the toolbox and put the picture
>driectly into screen memory. And speaking of screen memory, is the shadowing 
>of banks 00 and 01 always on, or is it neccesary to activate it somehow?

The internal format of the $C1 type pictures is contained in an Apple
File Type Note, named "ftn.c1.xxxx". "xxxx" is the auxtype designation for
the particular format (DeluxePaint uses its own format).  It's available
via anonymous FTP from apple.com.  It's in the /pub/dts/aii/ftn directory.

I assume you mean having QuickDraw draw directly to the FAST (2.8MHz)
side of memory, and having the hardware shadow your writes to slow memory,
thus making graphics manipulation faster.  Start up QuickDraw with the normal 
resolution descriptor, plus $8000 (I don't remember off the top of my head what
the standard values are).  
--
Jawaid Bazyar               | Blondes in big black cars look better wearing
Senior/Computer Engineering | their dark sunglasses at night. (unk. wierdo)
jb10320@uxa.cso.uiuc.edu    |      The gin, the gin, glows in the Dark!
   Apple II Forever!        |                             (B O'Cult)
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