From: barrett@iastate.edu (Marc N Barrett)
Subject: Re: A4000+DOMINO !!!
Followup-To: comp.sys.amiga.graphics
Keywords: A4000, DOMINO GFX BOARD
Organization: Iowa State University, Ames, IA
Date: Wed, 30 Sep 1992 17:01:51 GMT

In article <1992Sep30.164858@cc4.kuleuven.ac.be> stud11@cc4.kuleuven.ac.be (Lode Vande Sande) writes:
>
>
>        Hi there, all you guys in NetLand ...
>
>
>
>        The  holidays  are  over and Commodore has launched the A4000.  I'm
>interested  in  buying such a beasty, but before I do that, I would like to
>see a few questions answered ...
>
>        If  I'm  correct, the performance of the AA chip set depends on the
>type  of ram chips you use for your CHIP ram.  Is this true ?  If so, could
>anyone  please  tell  me exactly what this means and with what kind of CHIP
>ram the A4000 comes with out the box ?

   The A4000 comes with 2M of chip RAM, which is the most that the Alice
chip (replacement for Agnus) can address.  I assume that Commodore is using
the types of RAM chips that optimize the performance of the Amiga graphics
system.

>        It  seems  to  me that all custom chips now have 32 bit data-busses
>(That's  what  it  says  in  the  German  Amiga  mag.), however in the same
>article,  the  Amiga  mag.  claims that the copper has not changed ...  Can
>someone please enlighten me ?

   No, the copper has not been improved at all.  Among other things, this 
means that things like pull-down screens will have even greater restrictions
than before.  For example, there is now an 11-scanline blank space between
pull-down screens, instead of the 2-scanline space required for Amigas with
older chipsets.

>        The  A4000's display can range upto 1280x512 (maybe higher, I don't
>know), but the question is :  is this interlaced ?  

   Yes, the 1280x512 mode is interlaced.  Even worse, it is interlaced with
a field rate of 25Hz.  

>I have read that the AA
>chip  set  can  produce  non-interlaced displays, but can it do this in all
>these  resolutions  ?  

   No.

   The A4000 offers exactly the same non-interlaced modes as the A3000 with
the Display Enhancer turned on.  The Display Enhancer has effectively been
moved internally to the Lisa chip, but the non-interlaced modes offered are
exactly the same.  The highest non-interlaced resolutions offered by the 
A4000 are 720x480 60Hz NTSC and 720x560 50Hz PAL.  No higher non-interlaced
resolutions are possible.

   In addition, you may have heard about an 800x600 mode, but this mode is
interlaced at 72Hz (field rate of 36Hz), and has a horizontal frequency of
24.62Khz.  It is not usable on any VGA monitors, and few multisync monitors
will support it.  Even if you do find a monitor that supports the rather low
frequency of 24.62Khz, the monitor must also support interlacing.  And even
if you do find a monitor that supports the 24.62Khz frequency and interlacing,
the display will not be nearly as sharp as a VGA 800x600 non-interlaced 
display.  I would ignore the 800x600 mode if I were you.

>Is the 640x960 productivity without flicker ?

   No, the 640x960 Productivity Interlaced mode is still interlaced, and
not available as non-interlaced.

>  This
>would  mean  that they would use 62KHz if I'm not mistaken ...  Let's see :
>normal 640x200 -> 15KHz, productivity 640x480 (non-interlaced) -> 31KHz, so
>if  the  640x960  would  be  without flicker, it would have to have a 62KHz
>frequency,  isn't it ...  Again can anyone explain this to me/correct me on
>this ...

   It would also require 17.5nS pixels.

   The scan-doubler and promoter (the replacement for the A3000's Display
Enhancer) only supports the 15Khz NTSC and PAL modes.  No other modes can
be deinterlaced.

>	I've  seen  some  postings here that Commodore would be putting in
>on-board  SCSI,  a  DSP  and  16-bit  sound  by X-mas.  Ok, I know this is
>advocacy,  but I really would like to get something for my money, so could
>someone  please  tell me if this has been confirmed or at least heard from
>several independant sources ?

   I will believe it when I see it.  I am not expecting Commodore to be 
bringing out any new systems with SCSI or DSPs as standard hardware within the
next six months.  Commodore may bring out a Zorro II/III SCSI II card and a
Zorro II/III card with a DSP, but since the hardware is not standard with
the systems, the software support will suffer.  

>        And  as a last question :  will there be an A4000 Tower ?  Does the
>A4000 have enough free space to install a Syquest ?  (They told me that the
>A3000 didn't).

   I've heard rumors of an A4000T, but they were just rumors.

>+----------------+-------------------+------------------------------------+
>|/////\\_____\\\\|                   |                                    |
>|//// /_____ \\\\|  Kurt Haenen      |  Tjee, with this new cruncher,     |
>|/// /\____//\\\\|  Homsemstraat 53  |  I can put two times as many disks |
>|\\\/\ \   / / \\|  3891 Borlo       |  in one box than I used to ...     |
>|\\\/\\ \ / /\/\\|___________________|____________________________________|
>|\\\/\\\/_\/\/ //|                                       |                |
>| Kurt \/_\ / ///|  EMAIL : STUDxx @ CC4.KULEUVEN.AC.BE  | 2B || !2B T^ = |
>| Haenen  \\\/// |                                       | THE QUESTION ! |
>+----------------+---------------------------------------+----------------+

---
| Marc Barrett -MB-  |  email: barrett@iastate.edu
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Newsgroups: comp.sys.amiga.graphics