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re DMA hard disks [message #293625] Sat, 29 November 1986 10:52 Go to next message
Anonymous
Karma:
Originally posted by: spencer@well.UUCP (Randal Spencer)
Article-I.D.: well.2135
Posted: Sat Nov 29 10:52:54 1986
Date-Received: Sat, 29-Nov-86 20:57:47 EST
Organization: Whole Earth Lectronic Link, Sausalito, CA
Lines: 27

Really, is that true?  If you get a hard disk that is DMA it has a DMA chip in
it that is completely seperate from the Amiga DMA circuitry?  So that must be
how the PC hard disks can be said to be DMA also.  So what does that mean for
the lowly 3.5" floppies?  They don't have their own DMA circuitry so do they
DMA only to chip memory and not to fast memory?  Is it definate that when 
an advertiser says that their hard disk is DMA then they mean that they have 
one of those full memory DMA's and are not just using the Amiga DMA to Chip
memory?  How does the sidecar do it? or is the side car just going to be slow?
Is the sidecar going to have 2 meg of sockets for Amiga memory and sockets to
bring the IBM memory up to 640K and an 8087 co-processor socket and is it going
to reach the market?

You know, in psychology (my sisters graduate degree) they say that the most
boring way to make conversation is to just keep asking questions.  So I thought
I would provide this last piece of information to spice up this letter.



-- 
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Randy Spencer P.O. Box 4542 Berkeley CA 94704 (415)284-4740 ...well!spencer
                         I N F I N I T Y             spencer@USCVAXQ.bitnet
Now working for          |||||||||||::::... . .     spencer@usc-oberon.arpa  
But in no way            |||||||||||||||::::.. .. . .
Officially representing  ||||||||||||:::::... .. 
                         s o f t w a r e 
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Re: re DMA hard disks [message #293735 is a reply to message #293625] Wed, 03 December 1986 11:44 Go to previous messageGo to next message
Anonymous
Karma:
Originally posted by: andy@cbmvax.cbm.UUCP (Andy Finkel)
Article-I.D.: cbmvax.1048
Posted: Wed Dec  3 11:44:43 1986
Date-Received: Thu, 4-Dec-86 09:04:01 EST
References: <2135@well.UUCP>
Reply-To: andy@cbmvax.UUCP (Andy Finkel)
Organization: Commodore Technology, West Chester, PA
Lines: 44

In article <2135@well.UUCP> spencer@well.UUCP (Randal Spencer) writes:
 > Really, is that true?  If you get a hard disk that is DMA it has a DMA chip in
 > it that is completely seperate from the Amiga DMA circuitry? 
Yes, its true.
 So that must be
 > how the PC hard disks can be said to be DMA also.  So what does that mean for
 > the lowly 3.5" floppies?  They don't have their own DMA circuitry so do they
 > DMA only to chip memory and not to fast memory?  
This is also true.  The trackdisk.device (which talks to the floppies)
user the blitter.
Is it definate that when 
 > an advertiser says that their hard disk is DMA then they mean that they have 
 > one of those full memory DMA's and are not just using the Amiga DMA to Chip
 > memory?  
I'd call and ask, personally.  Byte-By-Byte's has a DMA chip.

How does the sidecar do it? or is the side car just going to be slow?
voodoo.
 > Is the sidecar going to have 2 meg of sockets for Amiga memory and sockets to
 > bring the IBM memory up to 640K and an 8087 co-processor socket and is it going
 > to reach the market?
The answe to that last question is yes, it is going to reach the
market.  It is already available in Germany, I'm told.
 > 
 > You know, in psychology (my sisters graduate degree) they say that the most
 > boring way to make conversation is to just keep asking questions.  So I thought
 > I would provide this last piece of information to spice up this letter.
 > 
 > -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
 > Randy Spencer P.O. Box 4542 Berkeley CA 94704 (415)284-4740 ...well!spencer

				andy finkel
-- 

			andy finkel
			Commodore/Amiga
			{ihnp4|seismo|allegra}!cbmvax!andy
		or	 pyramid!amiga!andy

Any expressed opinions are mine; but feel free to share.

I disclaim all responsibilities, all shapes, all sizes, all colors.

"Never make anything simple and efficient when it can be complex and wonderful."
Re: re DMA hard disks [message #293737 is a reply to message #293625] Wed, 03 December 1986 14:47 Go to previous messageGo to next message
Anonymous
Karma:
Originally posted by: daveh@cbmvax.cbm.UUCP (Dave Haynie)
Article-I.D.: cbmvax.1051
Posted: Wed Dec  3 14:47:00 1986
Date-Received: Thu, 4-Dec-86 09:09:57 EST
References: <2135@well.UUCP>
Organization: Commodore Technology, West Chester, PA
Lines: 58

 >  
 >  Really, is that true?  If you get a hard disk that is DMA it has a DMA chip 
 >  .. completely seperate from the Amiga DMA circuitry?  So what does that mean for
 >  the lowly 3.5" floppies?  They don't have their own DMA circuitry so do they
 >  DMA only to chip memory and not to fast memory?  

True.  If you go down to the lowest levels of 3 1/2" interface software,
you're required to supply a 512 byte disk buffer in Chip memory, and of
course the normal track buffer is as well in chip memory.  The actual 
decoding of the MFM encoded data is done with the Amiga's blitter, which
requires Chip memory.

 >  Is it definate that when 
 >  an advertiser says that their hard disk is DMA then they mean that they have 
 >  one of those full memory DMA's and are not just using the Amiga DMA to Chip
 >  memory?  How does the sidecar do it? or is the side car just going to be slow?
 >  

Any external DMAed device will have to be a DMA device in the conventional
sense; you can't use the Agnus supplied DMA to talk to external DMA devices;
remember, this DMA can only take place over the 512K range of Chip memory,
and is driven by the custom chips.  An external DMA must be driven by an
external DMA controller, though the rest of the system, being quite used
to DMAs happening, will oblige that external DMA.  The DMA can be to the Chip
memory or any fast memory, base on the abilities of the external controller.
The SideCar works though shared memory; an area of the Sidecar memory is
accessable to both the PC and Amiga sides.

 >  Is the sidecar going to have 2 meg of sockets for Amiga memory and sockets to
 >  bring the IBM memory up to 640K and an 8087 co-processor socket and is it going
 >  to reach the market?

Last I saw, the SideCar would accept an internal Amiga side memory expansion
board, though its not just filling sockets.  The basic configurations are 
256K and 512K I think, and the 256K version has the sockets available to add
another 256K for a total of 512K.  There is an 8087 socket, and the SideCar
is already being sold in Canada; don't know how long before its in the US.

 >  -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
 >  Randy Spencer P.O. Box 4542 Berkeley CA 94704 (415)284-4740 ...well!spencer
 >                           I N F I N I T Y             spencer@USCVAXQ.bitnet
 >  Now working for          |||||||||||::::... . .     spencer@usc-oberon.arpa  
 >  But in no way            |||||||||||||||::::.. .. . .
 >  Officially representing  ||||||||||||:::::... .. 
 >                           s o f t w a r e 
 >  -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Dave Haynie	{caip,ihnp4,allegra,seismo}!cbmvax!daveh

	"Laws to supress tend to strengthen what they would prohibit.
	 This is the fine point on which all the legal professions of
	 history have based their job security."
						-Bene Gesserit Coda

These opinions are my own, though for a small fee they may be yours too.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Re: re DMA hard disks [message #293905 is a reply to message #293625] Tue, 09 December 1986 11:27 Go to previous message
Anonymous
Karma:
Originally posted by: john13@garfield.UUCP
Article-I.D.: garfield.3103
Posted: Tue Dec  9 11:27:01 1986
Date-Received: Wed, 10-Dec-86 05:21:25 EST
References: <2135@well.UUCP> <1048@cbmvax.cbmvax.cbm.UUCP>
Sender: perry@garfield.UUCP
Reply-To: john13@garfield.UUCP (John Russell)
Organization: Memorial U. of Nfld. C.S. Dept., St. John's
Lines: 64
Summary: 

In article <1048@cbmvax.cbmvax.cbm.UUCP> andy@cbmvax.UUCP (Andy Finkel) writes:
 > In article <2135@well.UUCP> spencer@well.UUCP (Randal Spencer) writes:
 > How does the sidecar do it? or is the side car just going to be slow?
 > voodoo.
 >> Is the sidecar going to have 2 meg of sockets for Amiga memory and sockets to
 >> bring the IBM memory up to 640K and an 8087 co-processor socket and is it going
 >> to reach the market?
 > The answe to that last question is yes, it is going to reach the
 > market.  It is already available in Germany, I'm told.
 >> 

Well, you have now been informed that it's available here in the Great White 
North :-).

The PC hard-card we stuck in is partitionable, as many Amiga partitions as you 
want but only one IBM partition (I can see that's going to become another one of
*those* words - like "implementation" or "algorithm" :-). 

Hard drive speed boost we haven't measured yet. It is, of course, mega-fast
compared to floppies.

There is a spot for a 1 meg Amiga expansion, but any internal IBM type memory
can't be accessed by the Amiga. It doesn't pass the bus, but does pass the
mouse/joystick ports. Haven't had it apart yet, but the boot-up message makes
mention of Phoenix... well, Phoenix something. This would lead me to believe
that the internals are PC-10 identical. 256K comes in the Sidecar.

The manual does say not to use the Amiga power switch...but someone who shall
remain nameless (not me) forgot this twice and didn't blow anything up.

It multitasks wonderfully, even has slider gadgets for the IBM window (but
you can also make it full-screen and borderless if you want). What I saw was
all on the Workbench screen. Everything tried so far (we threw all our graphics
demos at it to try to crash it) has worked without a hitch. The manual says
"ALL IBM software". If the internals are PC-10ish, well, I've never seen
anything not work on the PC-10.

The German influence is present. You return to the "menue" and make the drive
"aktive". But the manual is professionally printed, unlike many of the
"preliminary version" manuals supplied even with some commercial products.

That's about all I have time for for now. If I get the time between now and
the end of exams, I will post info on any new products I see (let's have
some more reviews!). Until then, feel free to e-mail any questions you may
have on:

DPaint II (this will take a *long* time to review! Is there a "software of the 
           century" award? he says without smiley)
Pro Video Character Generator
Professional Text Engine
Sidecar (of course)

These are the latest/best products out this way. Someone please kick me if
I forget to follow through with reviews :-).

I see an ad for "Pagesetter" in the latest AmigaWorld. Is this a port of a 
Mac program? There is a *lot* of impressive stuff advertized & reviewed in 
that AmigaWorld, but their Q & A section could use help. "It's true that you 
can't have icons for directories created with the CLI..."

John Russell
UUCP:	{akgua,allegra,cbosgd,ihnp4,seismo,utcsri}!garfield!john13
EAN:	john13@garfield.mun.cdn
CSNET:  john13%garfield.mun.cdn@ubc.csnet
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